ScienceDirect Search: pub-date > 2008 and AFFILIATION("international livestock research") or AFFILIATION("ILRI")

The use of biogeochemical models to evaluate mitigation of greenhouse gas emissions from managed grasslands

15 November 2018

Publication date: 15 November 2018
Source:Science of The Total Environment, Volume 642

Author(s): Renáta Sándor, Fiona Ehrhardt, Lorenzo Brilli, Marco Carozzi, Sylvie Recous, Pete Smith, Val Snow, Jean-François Soussana, Christopher D. Dorich, Kathrin Fuchs, Nuala Fitton, Kate Gongadze, Katja Klumpp, Mark Liebig, Raphaël Martin, Lutz Merbold, Paul C.D. Newton, Robert M. Rees, Susanne Rolinski, Gianni Bellocchi

Simulation models quantify the impacts on carbon (C) and nitrogen (N) cycling in grassland systems caused by changes in management practices. To support agricultural policies, it is however important to contrast the responses of alternative models, which can differ greatly in their treatment of key processes and in their response to management. We applied eight biogeochemical models at five grassland sites (in France, New Zealand, Switzerland, United Kingdom and United States) to compare the sensitivity of modelled C and N fluxes to changes in the density of grazing animals (from 100% to 50% of the original livestock densities), also in combination with decreasing N fertilization levels (reduced to zero from the initial levels). Simulated multi-model median values indicated that input reduction would lead to an increase in the C sink strength (negative net ecosystem C exchange) in intensive grazing systems: −64 ± 74 g C m⁻² yr⁻¹ (animal density reduction) and −81 ± 74 g C m⁻² yr⁻¹ (N and animal density reduction), against the baseline of −30.5 ± 69.5 g C m⁻² yr⁻¹ (LSU [livestock units] ≥ 0.76 ha⁻¹ yr⁻¹). Simulations also indicated a strong effect of N fertilizer reduction on N fluxes, e.g. N2O-N emissions decreased from 0.34 ± 0.22 (baseline) to 0.1 ± 0.05 g N m⁻² yr⁻¹ (no N fertilization). Simulated decline in grazing intensity had only limited impact on the N balance. The simulated pattern of enteric methane emissions was dominated by high model-to-model variability. The reduction in simulated offtake (animal intake + cut biomass) led to a doubling in net primary production per animal (increased by 11.6 ± 8.1 t C LSU⁻¹ yr⁻¹ across sites). The highest N2O-N intensities (N2O-N/offtake) were simulated at mown and extensively grazed arid sites. We show the possibility of using grassland models to determine sound mitigation practices while quantifying the uncertainties associated with the simulated outputs.

Graphical abstract

The carbon balance of a Scots pine forest following severe windthrow: Comparison of reforestation techniques

15 October 2018

Publication date: 15 October 2018
Source:Agricultural and Forest Meteorology, Volumes 260–261

Author(s): K. Ziemblińska, M. Urbaniak, L. Merbold, T.A. Black, A.M. Jagodziński, M. Herbst, Ch. Qiu, J. Olejnik

Even though windthrows are the main disturbance type in European forests, their impact on forest carbon balance is generally understudied. In order to close this knowledge gap, we took advantage of a tornado event, which occurred in July 2012 in Trzebciny Forest District in northwest Poland. The main objective of this study was to determine how two completely different reforestation techniques in windthrow areas impact net ecosystem production (NEP) of this Scots pine forest ecosystem under similar meteorological conditions. The two techniques were: conventional (“Tlen I” site): uprooted stumps pulled out and removed from the site followed by ploughing, and non-conventional (“Tlen II” site): all stumps left on the site to decompose with no ploughing. Therefore, we measured carbon dioxide (CO2) fluxes using the eddy covariance (EC) technique for four continuous years. Our results indicate that both sites became significant carbon (C) sources after the windthrow (up to 575 ± 56 g C m⁻² y^-1 in the first year, Tlen I). However, the Tlen I (conventional technique) lost over 30% less C than Tlen II during the 2015–2016 observation period. In contrast to existing knowledge, ploughing as done at Tlen I, did not substantially increase CO2 emission, as compared to local soil ripping (non-conventional technique). The decrease in net C emission, estimated on the basis of linear model parameters, was almost five times greater at Tlen I than at Tlen II. We thus hypothesize that the annual NEP at conventionally reforested windthrow site will reach C neutrality (NEP = 0) six years after windthrow at most, while at the non-conventionally managed area it will probably take ca. 18 years. So far then, the currently widely applied conventional reforestation technique in wind-disturbed Polish forest appeared to be more effective in decreasing C losses than a technique that leaves stumps to decompose and avoids ploughing.

Combining ability and nature of gene action in maize (Zea mays L) inbred lines for resistance to gray leaf spot disease (Cercospora zeae maydis) in Ethiopia

October 2018

Publication date: October 2018
Source:Crop Protection, Volume 112

Author(s): Zelalem Bekeko, Chemeda Fininsa, Dagne Wegary, Temam Hussien, Shimelis Hussien, Belachew Asalf

Ten elite maize inbred lines were selected based on all over per se performance and gray leaf spot disease reaction. Crosses were made in a 10 × 10 half-diallel mating design to produce 45 F1 single cross hybrids. The experiment was conducted at Bako national maize research center in 2015 and evaluation of the crosses were made at Bako and Jimma research centers in 2016 by using alpha lattice design with three replications including three commercial checks. All the necessary yield, agronomic and GLS disease data were recorded. In all the studied traits highly significant genotypic differences were observed indicating the existence of genetic variability among the crosses. Analysis of variance for the combining ability indicated GCA and SCA mean squares were significant at (P < 0.001) for all traits except for anthesis-silking interval, ear per plant, ear diameter, lesion length and width. The ratios of GCA/SCA variances for agronomic parameters and all disease parameters were greater than unity except for that of first disease appearance implying the predominance of additive gene actions. Among all inbred lines, P1, P4, P7, P8 and P9 were identified as desirable sources of resistant genes for GLS disease resistance with positive days of first disease appearance and negative disease incidence, severity and AUDPC values for GCA effects. From the analysis of epidemiological data and disease progress curves the Logistic model (R² = 96.5) better described the disease progress curves than the Gompertz model (R² = 92.5) indicating the presence of delayance in epidemics and the inflection point of the GLS. P1, P7 and P8 were identified as a good general combiners for yield, yield related traits and GLS disease parameters. Thus, these parents were recommended to be used in breeding programs with a purpose of developing high yielder and GLS resistant single cross hybrids. In conclusion this study identified potential high yielding and GLS resistant single cross hybrids (CML-395/CML-383, CML-395/Sc-22, CML-395/CML-197 and CML-383/CML-197). Therefore, it is recommended that these hybrids can be used for direct production where this disease is the most prevalent and/or for further breeding programs in generating novel hybrids for future use.

Optimizing yield and economic returns of rain-fed potato (Solanum tuberosum L.) through water conservation under potato-legume intercropping systems

30 September 2018

Publication date: 30 September 2018
Source:Agricultural Water Management, Volume 208

Author(s): Harun I. Gitari, Charles K.K. Gachene, Nancy N. Karanja, Solomon Kamau, Shadrack Nyawade, Kalpana Sharma, Elmar Schulte-Geldermann

Even though potato (Solanum tuberosum L.)-based intercropping systems are widely practised in developing countries, only a few studies have focused on legumes as the companion intercrops. This study was conducted to assess the effect of incorporating legumes into the potato production system on ground cover, soil moisture content (SMC), tuber and legume yield, potato equivalent yield (PEY), gross and net income and benefit: cost ratio (BCR). The treatments comprised of pure potato stand (PS), potato-dolichos (Lablab purpureus L.) (PD), potato-garden pea (Pisum sativum L.) (PG) and potato-bean (Phaseolus vulgaris L.) (PB). Results indicated a significantly higher (69%) ground cover at tuber initiation stage in PD compared to 66% in PG and PB and 56% in PS. Similarly, the highest SMC values were recorded at tuber initiation stage: 230, 207, 201 and 188 mm m−1 in PD, PG, PB and PS, respectively. Fresh tuber yield was highest in PS (36 t ha−1) and PD (35 t ha−1) and lowest in PG (29 t ha−1). PEY was higher under intercropping than monocropping systems. Potato-dolichos was the most profitable intercropping system with a net income of US$ 9174 ha−1 and a BCR of 5.7 compared to PS (US$ 7436 ha−1) with a BCR of 5.1. The study showed that dolichos is a promising legume crop that could be integrated into potato cropping systems to improve CWP without compromising the tuber yield.

Is agricultural adaptation to global change in lower-income countries on track to meet the future food production challenge?

September 2018

Publication date: September 2018
Source:Global Environmental Change, Volume 52

Author(s): Philip K Thornton, Patricia Kristjanson, Wiebke Förch, Carlos Barahona, Laura Cramer, Sonali Pradhan

Agriculture is critical to sustainable development, and agricultural production by smallholders in lower-income countries contributes substantially to the food security of both rural and urban populations. Smallholders face many challenges related to urbanisation, sustainable use of natural resources and climate change. While there will be different ways of achieving sustainable agricultural systems, all will involve adaptation on a massive scale to meet the future food production challenge at greatly reduced carbon cost. Here we evaluate recent progress in agricultural adaptation using surveys in five regions, 21 countries and 45 sites, covering 315 villages and approximately 6300 households. These surveys include information about the changes made to farming systems in the last decade. We synthesise this information by grouping households into types: food insecure, hanging in, stepping up and stepping out. We then profile each site in terms of its proportion of households of these four types. While farmers have made some changes in their farming practices over the last decade, most changes have been incremental and piecemeal. We find little evidence in the study sites in any region of farming changes at the scale needed to enhance food security of significant proportions of the population. Searching for commonalities in the enabling environment among sites with similar proportions of household types, we found collective action at the community level coupled with appropriate climate information provision and the active participation of local organisations to be associated with higher levels of food security. To foster the changes needed in agricultural and food systems, a much stronger focus will be required on the enabling environment if food security goals are to be attainable. Without more nuanced and effective targeting of technological as well as institutional interventions, agricultural adaptation to meet the food production challenge in the coming decades is unlikely to occur.

Multi-objective land use allocation modelling for prioritizing climate-smart agricultural interventions

10 August 2018

Publication date: 10 August 2018
Source:Ecological Modelling, Volume 381

Author(s): A. Dunnett, P.B. Shirsath, P.K. Aggarwal, P. Thornton, P.K. Joshi, B.D. Pal, A. Khatri-Chhetri, J. Ghosh

Climate-smart interventions in agriculture have varying costs and environmental and economic impacts. Their implementation requires appropriate investment decisions by policy makers that are relevant for current as well as future scenarios of agro-ecology, climate and economic development. Decision support tools are therefore needed to assist different stakeholders to prioritize and hence implement appropriate strategic interventions. These interventions transform agriculture ecosystems to climate-resilient, adaptive and efficient. This paper outlines the mathematical modelling framework of one such, the Climate Smart Agricultural Prioritization (CSAP) toolkit. This toolkit employs a dynamic, spatially-explicit multi-objective optimization model to explore a range of agricultural growth pathways coupled with climate-adaptation strategies to meet agricultural development and environmental goals. The toolkit consists of three major components: (i) land evaluation including assessment of resource availability, land suitability, yield and input-output estimation for all promising crop production practices and technologies for key agro-ecological units; (ii) formulation of scenarios based on policy views and development plans; and (iii) land-use optimization in the form of linear programming models. Climate change and socio-economic drivers condition the land evaluation, technological input-output relations, and specification of optimization objectives that define modelled scenarios. By integrating detailed bottom-up biophysical, climate impact and agricultural-emissions models, CSAP is capable of supporting multi-objective analysis of agricultural production goals in relation to food self-sufficiency, incomes, employment and mitigation targets, thus supporting a wide range of analyses ranging from food security assessment to environmental impact assessment to preparation of climate smart development plans.

Defining smallholders’ sheep breeding objectives using farmers trait preferences versus bio-economic modelling

August 2018

Publication date: August 2018
Source:Livestock Science, Volume 214

Author(s): Solomon Gizaw, Ayele Abebe, Asfaw Bisrat, Tesfaye Zewdie, Azage Tegegne

In this study we defined smallholders’ sheep breeding objectives using farmers’ trait preferences through a proportional-piling tool and a bio-economic model to evaluate the congruence between the two breeding objectives. We took Menz sheep of Ethiopia as a case study. Multinomial logistic regression analysis showed that there were no statistically significant differences among weights allocated by farmers to growth rate, survival and lambing interval, which formed the high priority traits for Menz farmers. The likelihood of farmers attaching more weight to these three traits was significantly higher than they do to 6-month weight, mature weight, fleece weight and litter size (odds ratio = 1.16 to 2.32, P < 0.001). The percentage of farmers who allocated the highest weights to 6-month weight, mature weight, fleece weight, litter size, growth rate, lambing interval and survival were 0.0, 2.1, 0.0, 2.1, 37.5, 29.2 and 29.2%, respectively. Survival, lambing interval, growth rate and 6-month weight were found to be the most economically important traits using a bio-economic model. A genetic improvement by one σa in these traits resulted in a profit of Birr 31.80 to 58.68 per ewe per year. The average of the correlations between economic values of traits and individual farmers’ trait weights was 0.591 ± 0.231, indicating a fair congruence between farmers’ preferences for traits and economic values of traits. There is a fair congruence between farmers’ preferences for traits and economic values of traits, both in terms of the rankings of traits and their relative weights. This would indicate that weighting traits in selection indexes with farmers’ trait ratings using quantitative methods such as proportional-piling (a simple visual method suitable for illiterate smallholders) would direct genetic improvement towards desired profitability with reasonable accuracy. Conversely, the fair correspondence between the two methods suggests that bio-economic modelling, if designed properly considering farmers concerns, could fairly be used to reflect farmers’ breeding objectives. However, since both methods suffer from drawbacks, complementary use of farmers’ trait preferences and bio-economic modeling would enable the combination of farmers’ indigenous knowledge and choices and the genetic properties of traits and their accurate economic values. This combined approach would enable to arrive at breeding objectives that would result in rapid and profitable genetic progress while maintaining the adaptability of the local genetic resource. This would involve multiple engagements between experts and villagers unlike the usual one-off survey of farmers’ preferences. Further research on the modalities for complementary use of the two methods to define breeding objectives under smallholder conditions is warranted.

Prevalence, risk factors and molecular characterization of Cryptosporidium infection in cattle in Addis Ababa and its environs, Ethiopia

August 2018

Publication date: August 2018
Source:Veterinary Parasitology: Regional Studies and Reports, Volume 13

Author(s): Anberber Manyazewal, Stomeo Francesca, Mahendra Pal, Mamo Gezahegn, Mulatu Tesfaye, Muthui Lucy, Wegayehu Teklu, Tilahun Getachew

A cross-sectional study was conducted to determine the prevalence and risk factors of Cryptosporidium infection and identify species of the parasite in cattle in central Ethiopia. Faecal samples, collected from 392 dairy cattle managed under intensive and extensive production system, were analyzed by the Modified Ziehl-Neelsen (MZN) microscopy, Nested PCR, PCR-RFLP and sequence analyses of the SSU rRNA gene of Cryptosporidium. The overall prevalence, the prevalence in the extensive and intensive farms was 18.6%, 11% and 21%, respectively. The infection was detected in 37.7% of the investigated farms with prevalence range of 7.4% -100%, and all of the six surveyed districts with significant (P = 0.000) prevalence difference. Restriction digestion and sequence analysis showed Cryptosporidium parvum and C. andersoni in 27% and 73% of the infections, respectively, showing an age related distribution pattern, C. parvum exclusively occurring in calves <2 months old and C. andersoni only in heifers and adult cattle. The infection was significantly associated with management system, farm location, herd size, source of drinking water, weaning age, presence of bedding, pen cleanness and cleanness of hindquarter. In conclusion, Cryptosporidium infection due to C. parvum and C. andersoni was prevalent in cattle in the study area. Cryptosporidium parvum has the concern of public health importance, especially to farm workers and people in close contact with cattle. Instigation of imperative control measure is suggested to lessen the risk of human infection and loss of production in dairy farms.

Rethinking identity in adaptation research: Performativity and livestock keeping practices in the Kenyan drylands

August 2018

Publication date: August 2018
Source:World Development, Volume 108

Author(s): Julia Wernersson

Adaptation research often uses identity categories. This article argues that a performativity approach allows us to understand identity in ways that are important for adaptation. Performativity sees identity as constructed through practices in an ongoing process of negotiation and renegotiation. Individuals and groups can thus be understood as having the agency to redefine identity by changing their everyday practices; changed practices, in turn, can influence the construction of identity.

Drawing on ethnographic fieldwork conducted with pastoral and agro-pastoral livestock keepers in West Pokot County, Kenya, the article focuses on one set of identity-linked and adaptation-relevant practices: those involved in ensuring that livestock receive water regularly. Practices of livestock keeping reveal how identity is both implicated by and constructs the social context – between and within individuals, families, and communities, but also in relation to livestock and wider biophysical phenomena. By focusing on the changing practices of livestock watering within a changing social and biophysical context, it is possible to extract not only normative practices, but also a number of practices that disturb settled patterns, contesting or resisting identity constructs. This agency to change practices and identity has important implications for adaptation, which also requires changes in practice and behaviour. As this diversity and fluidity of identity as constructed and practised in the present emerges, so do the different ideas of what it can and will mean to be a livestock keeper in relation to the contextual challenges of today and the future.

Gender lessons for climate initiatives: A comparative study of REDD+ impacts on subjective wellbeing

August 2018

Publication date: August 2018
Source:World Development, Volume 108

Author(s): Anne M. Larson, David Solis, Amy E. Duchelle, Stibniati Atmadja, Ida Aju Pradnja Resosudarmo, Therese Dokken, Mella Komalasari

Although REDD+ is primarily a mechanism for reducing carbon emissions from forests, concerns regarding social benefits, wellbeing and gender are increasingly part of its mandate. This is consistent with the Paris Declaration as well as SDG 5 on gender equality and women’s empowerment. Critics have argued, however, that REDD+ design, both in policy and projects, does not take gender into account effectively, rather marginalizing women from decision making processes and exacerbating inequalities. Most of that research has been site specific or on single countries. This article uses data from a longitudinal study of subnational REDD+ initiatives in six countries to analyze their gendered impact on perceived wellbeing. Comparative research on subjective wellbeing was conducted at 62 villages participating in 16 REDD+ initiatives and 61 control villages at two periods in time, using a before-after-control-intervention (BACI) design. Focus groups with villagers (68% male) and women (100% female) permit a gendered comparison of definitions of wellbeing and outcomes of initiatives. The results highlight that while definitions of wellbeing overlapped between the two groups, almost half of the women’s focus groups thought that having their own source of income was important. Outcomes regarding wellbeing change suggest that perceived wellbeing decreased in REDD+ villages both for villagers as a whole and for women, relative to control villages, but the decrease was much worse for women – a decrease that is significantly associated with living in a REDD+ village. These declines may be due to unrealized expectations for REDD+, combined with little attention to gender in REDD+ initiatives, in spite of an important portion (46%) of specific interventions that women view positively. These interventions provide insights into potential ways forward. Overall, however, REDD+ initiatives appear to be repeating past mistakes, with insufficient attention to gender equality and safeguarding women’s rights. More effort needs to be paid to ensuring that gender is an integral part of future initiatives to combat climate change in rural communities.

Comparative analysis of adaptive immune responses following experimental infections of cattle with bovine viral diarrhoea virus-1 and an Asiatic atypical ruminant pestivirus

16 July 2018

Publication date: 16 July 2018
Source:Vaccine, Volume 36, Issue 30

Author(s): Victor Riitho, Magdalena Larska, Rebecca Strong, S. Anna La Rocca, Nicolas Locker, Stefan Alenius, Falko Steinbach, Lihong Liu, Åse Uttenthal, Simon P. Graham

Atypical ruminant pestiviruses are closely related to the two bovine viral diarrhoea virus (BVDV) species, BVDV-1 and BVDV-2. While there is evidence of cross-protective immune responses between BVDV-1 and BVDV-2, despite antigenic differences, there is little information on the antigenic cross-reactivity with atypical ruminant pestiviruses. The aim of this study was therefore to assess the specificity of antibody and T cell responses induced by experimental infection of calves with BVDV-1 strain Ho916, Th/04_KhonKaen (TKK), an Asiatic atypical ruminant pestivirus, or co-infection with both viruses. Homologous virus neutralization was observed in sera from both single virus infected and co-infected groups, while cross-neutralization was only observed in the TKK infected group. T cell IFN-γ responses to both viruses were observed in the TKK infected animals, whereas Ho916 infected calves responded better to homologous virus. Specifically, IFN-γ responses to viral non-structural protein, NS3, were observed in all infected groups while responses to viral glycoprotein, E2, were virus-specific. Broader antigen-specific cytokine responses were observed with similar trends between inoculation groups and virus species. The limited T cell and antibody immune reactivity of Ho916 inoculated animals to TKK suggests that animals vaccinated with current BVDV-1-based vaccines may not be protected against atypical ruminant pestiviruses.

Rainfall variability and drought characteristics in two agro-climatic zones: An assessment of climate change challenges in Africa

15 July 2018

Publication date: 15 July 2018
Source:Science of The Total Environment, Volume 630

Author(s): Ayansina Ayanlade, Maren Radeny, John F. Morton, Tabitha Muchaba

This paper examines drought characteristics as an evidence of climate change in two agro-climatic zones of Nigeria and farmers' climate change perceptions of impacts and adaptation strategies. The results show high spatial and temporal rainfall variability for the stations. Consequently, there are several anomalies in rainfall in recent years but much more in the locations around the Guinea savanna. The inter-station and seasonality statistics reveal less variable and wetter early growing seasons and late growing seasons in the Rainforest zone, and more variable and drier growing seasons in other stations. The probability (p) of dry spells exceeding 3, 5 and 10 consecutive days is very high with 0.62≤ p ≥0.8 in all the stations, though, the p-values for 10day spells drop below 0.6 in Ibadan and Osogbo. The results further show that rainfall is much more reliable from the month of May until July with the coefficient of variance for rainy days <0.30, but less reliable in the months of March, August and October (CV-RD>0.30), though CV-RD appears higher in the month of August for all the stations. It is apparent that farmers' perceptions of drought fundamentally mirror climatic patterns from historical weather data. The study concludes that the adaptation facilities and equipment, hybrids of crops and animals are to be provided to farmers, at a subsidized price by the government, for them to cope with the current condition of climate change.

Graphical abstract

An empirical evaluation of policy options for inclusive dairy value chain development in Nicaragua: A system dynamics approach

July 2018

Publication date: July 2018
Source:Agricultural Systems, Volume 164

Author(s): Helene Lie, Karl M. Rich, Rein van der Hoek, Kanar Dizyee

Achieving inclusive value chain development is a challenging task due to the complex and dynamic nature of interconnected value chains and their social, economic, and ecological dimensions. While many policies and intervention options exist to upgrade value chains, there are fewer methods that can be used to understand and quantify the multidimensional impacts that value chain policies and interventions may have throughout the value chain. This paper addresses this methodological gap by employing a system dynamics (SD) modeling approach. SD models allow us to model and quantify the processes and relationships inherent in the value chain through simulations, serving as a policy laboratory for the empirical assessment of intervention options. An SD model of the Matiguás dairy value chain in Nicaragua was developed and tested through a participatory modeling process. Our research tested and evaluated the short-, medium-, and long-term impacts of specific interventions and policies in the Matiguás dairy value chain with the goal of strengthening the competitiveness and inclusion of small- and medium-scale producers. These interventions centered on improving the feeding system, which was identified by stakeholders as the critical constraint to competitiveness. The policy analysis reveals that both improved pastures and increased use of concentrates raise producer milk productivity by 5% and 11%, respectively in the long run, but are also expensive strategies for smallholder producers, leading to a reduction in profits relative to the baseline by 1% and 3%, respectively. Consequently, policymakers should identify strategies that help to reduce concentrate costs and support producers with investments in improved pasture, while also promoting training in pasture management skills. Indeed, in the long-run, model results reveal that investment and training in pasture management results in a 30% and 35% increase in milk production during the wet and dry season, respectively. Simulation results further highlighted that intensifying the feeding system to improve cow milk yields is mainly profitable in the long term, and thus requires a longer-term perspective by policymakers. The model provides a deeper understanding of the complex and dynamic nature of the Matiguás dairy value chain and the interactions between markets, coordination aspects, biophysical phenomena, and income. The system dynamics approach to value chain analysis further addresses a major analytical shortcoming in value chain analysis and provides decision makers with an improved platform for planning and policy formulation.

Additive yield response of chickpea (Cicer arietinum L.) to rhizobium inoculation and phosphorus fertilizer across smallholder farms in Ethiopia

1 July 2018

Publication date: 1 July 2018
Source:Agriculture, Ecosystems & Environment, Volume 261

Author(s): Endalkachew Wolde-meskel, Joost van Heerwaarden, Birhan Abdulkadir, Sofia Kassa, Ibsa Aliyi, Tulu Degefu, Kissi Wakweya, Fred Kanampiu, Ken E. Giller

The impacts of rhizobium inoculation on growth and yield of chickpea have mainly been tested in experiments conducted in greenhouses or on research stations. We report the response of the crop to inoculation (I) and phosphorus fertilizer (P) application across a large number of smallholder’s farms over four regions of Ethiopia, covering diverse soil fertility and agro-ecological conditions. Increased grain yields due to the soil fertility treatments was evident for 99% target farmers. On average, I and P increased grain yield by 21% and 25% respectively, while the combined application of I and P resulted in a 38% increase. However, observed grain yields on control plots and responses to the treatments on individual farms varied greatly, and relative yield responses (%; yield of P and/I minus control yield, divided by control yield) ranged from 3% to 138%. With the exception of a few extremely poorly yielding locations, average responses to P and I were high across a wide range of control yields, indicating the possibility of boosting chickpea productivity for smallholders with P fertilizer and inoculant technology. Variation in response to rhizobium inoculation was mostly independent of agro-ecology and soil type although it was found to be low on a number of farms with extremely high N contents (%). Assuming that a relative yield increase of 10% due to treatment effects is required to be visible, 71%, 73% and 92% of the farmers observed a yield benefit by applying P, I, and P + I, respectively. The results are discussed with respect to the additive benefits of P fertilizers and rhizobial inoculation and their implications for wide scale promotion of inoculant technology to smallholders.

Soyabean response to rhizobium inoculation across sub-Saharan Africa: Patterns of variation and the role of promiscuity

1 July 2018

Publication date: 1 July 2018
Source:Agriculture, Ecosystems & Environment, Volume 261

Author(s): Joost van Heerwaarden, Frederick Baijukya, Stephen Kyei-Boahen, Samuel Adjei-Nsiah, Peter Ebanyat, Nkeki Kamai, Endalkachew Wolde-meskel, Fred Kanampiu, Bernard Vanlauwe, Ken Giller

Improving bacterial nitrogen fixation in grain legumes is central to sustainable intensification of agriculture in sub-Saharan Africa. In the case of soyabean, two main approaches have been pursued: first, promiscuous varieties were developed to form effective symbiosis with locally abundant nitrogen fixing bacteria. Second, inoculation with elite bacterial strains is being promoted. Analyses of the success of these approaches in tropical smallholder systems are scarce. It is unclear how current promiscuous and non-promiscuous soyabean varieties perform in inoculated and uninoculated fields, and the extent of variation in inoculation response across regions and environmental conditions remains to be determined.

We present an analysis of on-farm yields and inoculation responses across ten countries in Sub Saharan Africa, including both promiscuous and non-promiscuous varieties. By combining data from a core set of replicated on-farm trials with that from a large number of farmer-managed try-outs, we study the potential for inoculation to increase yields in both variety types and evaluate the magnitude and variability of response.

Average yields were estimated to be 1343 and 1227 kg/ha with and without inoculation respectively. Inoculation response varied widely between trials and locations, with no clear spatial patterns at larger scales and without evidence that this variation could be explained by yield constraints or environmental conditions. On average, specific varieties had similar uninoculated yields, while responding more strongly to inoculation. Side-by side comparisons revealed that stronger responses were observed at sites where promiscuous varieties had superior uninoculated yields, suggesting the availability of compatible, effective bacteria as a yield limiting factor and as a determinant of the magnitude of inoculation response.

Integrated soil, water and agronomic management effects on crop productivity and selected soil properties in Western Ethiopia

Available online 30 June 2018

Publication date: Available online 30 June 2018
Source:International Soil and Water Conservation Research

Author(s): Teklu Erkossa, Timothy O. Williams, Fanuel Laekemariam

Land degradation is a major challenge limiting crop production in Ethiopia. Integrated soil and water conservation is widely applied as a means to reverse the trend and increase productivity. This study investigated the effects of such integrated approaches at two sites, Jeldu and Diga, in Western Ethiopia. A split plot design with physical soil and water conservation in the main plots and agronomic practices in the sub plots was employed. Maize (Zea mays L.) followed by groundnut (Arachis hypogaea L.) at Diga, and wheat (Triticum aestivum) followed by faba bean (Vicia faba L.) were the test crops. Surface soils were sampled before sowing and after the crop harvest, and analyzed for selected parameters. Soil moisture content during the growing period was also monitored. The use of soil bund increased soil moisture content, and significantly (P < 0.05) increased days to flowering and maturity, kernel weight and harvest index, grain yield of the test crops, with the exception of maize. The improved agronomic practices (intercropping, fertilization and row planting) significantly (P < 0.05) increased grain yield of all the test crops. The effect of the treatments on soil parameters may require longer time to be evident. Although the increase in crop yield due to soil bund and the improved agronomic practices is eminent, economic analysis is necessary before recommending the widespread use of the improved options.

Was chicken domesticated in northern China? New evidence from mitochondrial genomes

30 June 2018

Publication date: 30 June 2018
Source:Science Bulletin, Volume 63, Issue 12

Author(s): Xun-He Huang, Ya-Jiang Wu, Yong-Wang Miao, Min-Sheng Peng, Xing Chen, Dan-Lin He, Chatmongkon Suwannapoom, Bing-Wang Du, Xian-Yao Li, Zhuo-Xian Weng, Si-Hua Jin, Jiao-Jiao Song, Ming-Shan Wang, Jie-Bo Chen, Wei-Na Li, Newton Otieno Otecko, Zhao-Yu Geng, Xiang-Yong Qu, Yan-Ping Wu, Xiu-Rong Yang, Jie-Qiong Jin, Jian-Lin Han, Fu-Sheng Zhong, Xi-Quan Zhang, Ya-Ping Zhang

Integrated food safety and nutrition assessments in the dairy cattle value chain in Tanzania

Available online 19 June 2018

Publication date: Available online 19 June 2018
Source:Global Food Security

Author(s): Barbara Häsler, George Msalya, Maria Garza, Kimberly Fornace, Mahmoud Eltholth, Lusato Kurwijila, Jonathan Rushton, Delia Grace

The consumption of even small amounts of animal-source foods has the potential to improve nutrition, especially in vulnerable households. However, scaling up their production bears food safety risks that are often overlooked due to a disconnect between human nutrition and animal sciences. The aim of this scoping study in Tanzania was to identify opportunities for nutritional and food safety benefits from cow milk.

Questionnaires were administered to 156 producers and 157 consumers in 10 villages in Lushoto and Mvomero districts. Farmers reported that veterinary medicines such as oxytetracyclines, penicillin and streptomycin were frequently given to cattle, and a majority did not discard milk during or after treatment. Less than half of the producers boiled milk, although sale of fermented milk, made by spontaneous fermentation of raw milk, was common. Cattle management was characterised by low levels of biosecurity, hygienic practices and disease control. A majority of consumers reported not to have enough food to meet their family needs. The Food Consumption Score was acceptable for all households, but significantly higher for households with dairy cattle. When making purchasing decisions, the appearance of milk and trust in the supplier were more important considerations than hygiene practices observed. A total of 26% of consumers reported to consume raw milk “usually” or “sometimes” and 54% of consumers reported to drink fermented milk “usually” or “sometimes”. Consumers had a positive attitude towards milk and concern for quality but most thought there was no risk of illness from milk consumption.

The findings promote understanding of the complexity surrounding the local food environment and practices related to the production and consumption of dairy products and allow shaping recommendations for nutrition-sensitive livestock interventions.

Agricultural intensification scenarios, household food availability and greenhouse gas emissions in Rwanda: Ex-ante impacts and trade-offs

June 2018

Publication date: June 2018
Source:Agricultural Systems, Volume 163

Author(s): B.K. Paul, R. Frelat, C. Birnholz, C. Ebong, A. Gahigi, J.C.J. Groot, M. Herrero, D.M. Kagabo, A. Notenbaert, B. Vanlauwe, M.T. van Wijk

Rwanda's agricultural sector is facing severe challenges of increasing environmental degradation, resulting in declining productivity. The problem is likely to be further aggravated by the growing population pressure. A viable pathway is climate smart agriculture, aiming at the triple win of improving food security and climate change adaptation, while contributing to mitigation if possible. The Government of Rwanda has initiated ambitious policies and programs aiming at low emission agricultural development. Crop focused policies include the Crop Intensification Program (CIP) which facilitates access to inorganic fertilizer and improved seeds. In the livestock subsector, zero-grazing and improved livestock feeding are encouraged, and the Girinka program provides poor farm households with a crossbred dairy cow. In this study, we aimed at assessing the potential impact of these policy programs on food availability and greenhouse gas (GHG) emissions of 884 households across different agro-ecologies and farming systems in Rwanda. Household level calculations were used to assess the contribution of current crops, livestock and off-farm activities to food availability and GHG emissions. Across all sites, 46% of households were below the 2500kcalMAE⁻¹ yr⁻¹ line, with lower food availability in the Southern and Eastern Rwanda. Consumed and sold food crops were the mainstay of food availability, contributing between 81.2% (low FA class) to 53.1% (high FA class). Livestock and off-farm income were the most important pathways to higher FA. Baseline GHG emissions were low, ranging between 395 and 1506kg CO2e hh⁻¹ yr⁻¹ per site, and livestock related emissions from enteric fermentation (47.6–48.9%) and manure (26.7–31.8%) were the largest contributors to total GHG emissions across sites and FA classes. GHG emissions increased with FA, with 50% of the total GHG being emitted by 22% of the households with the highest FA scores. Scenario assessment of the three policy options showed strong differences in potential impacts: Girinka only reached one third of the household population, but acted highly pro-poor by decreasing the households below the 2500kcalMAE⁻¹ yr⁻¹ line from 46% to 35%. However, Girinka also increased GHG by 1174kg CO2e hh⁻¹ yr⁻¹, and can therefore not be considered climate-smart. Improved livestock feeding was the least equitable strategy, decreasing food insufficient households by only 3%. However, it increased median FA by 755kcalMAE⁻¹ yr⁻¹ at a small GHG increase (50kg CO2e hh⁻¹ yr⁻¹). Therefore, it is a promising option to reach the CSA triple win. Crop and soil improvement resulted in the smallest increase in median FA (FA by 322kcalMAE⁻¹ yr⁻¹), and decreasing the proportion of households below 2500kcalMAE⁻¹ yr⁻¹ by 6%. This came only at minimal increase in GHG emissions (23kg CO2e hh⁻¹ yr⁻¹). All policy programs had different potential impacts and trade-offs on different sections of the farm household population. Quick calculations like the ones presented in this study can assist in policy dialogue and stakeholder engagement to better select and prioritize policies and development programs, despite the complexity of its impacts and trade-offs.

Evaluating agricultural trade-offs in the age of sustainable development

June 2018

Publication date: June 2018
Source:Agricultural Systems, Volume 163

Author(s): David R. Kanter, Mark Musumba, Sylvia L.R. Wood, Cheryl Palm, John Antle, Patricia Balvanera, Virginia H. Dale, Petr Havlik, Keith L. Kline, R.J. Scholes, Philip Thornton, Pablo Tittonell, Sandy Andelman

A vibrant, resilient and productive agricultural sector is fundamental to achieving the Sustainable Development Goals. Bringing about such a transformation requires optimizing a range of agronomic, environmental and socioeconomic outcomes from agricultural systems – from crop yields, to biodiversity, to human nutrition. However, these outcomes are not independent of each other – they interact in both positive and negative ways, creating the potential for synergies and trade-offs. Consequently, transforming the agricultural sector for the age of sustainable development requires tracking these interactions, assessing if objectives are being achieved and allowing for adaptive management within the diverse agricultural systems that make up global agriculture. This paper reviews the field of agricultural trade-off analysis, which has emerged to better understand these interactions – from field to farm, region to continent. Taking a “cradle-to-grave” approach, we distill agricultural trade-off analysis into four steps: 1) characterizing the decision setting and identifying the context-specific indicators needed to assess agricultural sustainability, 2) selecting the methods for generating indicator values across different scales, 3) deciding on the means of evaluating and communicating the trade-off options with stakeholders and decision-makers, and 4) improving uptake of trade-off analysis outputs by decision-makers. Given the breadth of the Sustainable Development Goals and the importance of agriculture to many of them, we assess notions of human well-being beyond income or direct health concerns (e.g. related to gender, equality, nutrition), as well as diverse environmental indicators ranging from soil health to biodiversity to climate forcing. Looking forward, areas of future work include integrating the four steps into a single modeling platform and connecting tools across scales and disciplines to facilitate trade-off analysis. Likewise, enhancing the policy relevance of agricultural trade-off analysis requires improving scientist-stakeholder engagement in the research process. Only then can this field proactively address trade-off issues that are integral to sustainably intensifying local and global agriculture – a critical step toward successfully implementing the Sustainable Development Goals.

Crop vs. tree: Can agronomic management reduce trade-offs in tree-crop interactions?

1 June 2018

Publication date: 1 June 2018
Source:Agriculture, Ecosystems & Environment, Volume 260

Author(s): Tesfaye Shiferaw Sida, Frédéric Baudron, Kiros Hadgu, Abayneh Derero, Ken E. Giller

Scattered trees dominate smallholder agricultural landscapes in Ethiopia, as in large parts of sub-Saharan Africa (SSA). While the inclusion of scattered trees could provide a viable pathway for sustainable intensification of these farming systems, they also lead to trade-offs. We carried out a study to: 1) explore the rationale of farmers to maintain on-farm trees beyond crop yield; 2) quantify the impact of agronomic practices on the outcome of tree-crop interactions; and 3) analyse partial economic trade-offs for selected on-farm tree species at farm scale. We recorded agronomic practices within the fields of 135 randomly selected farms from seedbed preparation to harvesting. A multivariate analysis showed that farmers maintained on-farm trees because of their direct timber, fencing, fuelwood, and charcoal production values. Trees generally had a significant negative effect on maize yield. Mean grain yields of 1683, 1994 and 1752 kg ha⁻¹ under the canopies of Cordia, Croton and Acacia, respectively, were significantly lower than in their paired open field with mean yields of 4063, 3415 and 2418 kg ha⁻¹. Besides, more income from trees was accompanied by less income from maize, highlighting trade-offs. However, agronomic practices such as early planting, variety used, improved weed management, fine seedbed preparation and higher rates of nitrogen fertilizer significantly reduced yield penalties associated with trees. We found an inverse relationship between land size and on-farm tree density, implying that the importance of trees increases for land-constrained farms. Given the expected decline in per capita land size, scattered trees will likely remain an integral part of these systems. Thus, utilizing ‘good agronomic practices’ will be vital to minimize tree-crop trade-offs in the future.

Nitrogen and phosphorous uptake by potato (Solanum tuberosum L.) and their use efficiency under potato-legume intercropping systems

1 June 2018

Publication date: 1 June 2018
Source:Field Crops Research, Volume 222

Author(s): Harun I. Gitari, Nancy N. Karanja, Charles K.K. Gachene, Solomon Kamau, Kalpana Sharma, Elmar Schulte-Geldermann

Competition for nitrogen (N) and phosphorous (P) under potato-based intercropping systems decreases the level of nutrients available for potato and subsequently influences nitrogen and phosphorous use efficiency. A field trial was conducted for four consecutive seasons between 2014 short rains and 2016 long rains to assess the effect of incorporating legumes as intercrops into potato cropping systems on N and P uptake and uptake efficiency by the potato crop and nutrient use efficiency. The treatments included potato intercropped with either dolichos (Lablab purpureus L.) (PD), garden pea (Pisum sativum L.) (PG) or climbing bean (Phaseolus vulgaris L.) (PB), and a pure stand of potato (PS). Intercropping potato with beans and peas significantly reduced its N uptake by 22 and 27% relative to PS, but the N uptake was not affected under PD. Phosphorous uptake was 2, 8 and 11 kg P ha⁻¹ lower in PD, PB and PG, respectively compared with PS. Nitrogen use efficiency (NUE) was significantly higher in PD, PB and PG by 30, 19 and 9% compared with PS. Similarly, P use efficiency (PUE) was 6, 14 and 21% higher in PG, PB and PD, respectively than PS. The highest tuber yield recorded in PS (36 t ha⁻¹) did not significantly differ from PD (34 t ha⁻¹) whereas tuber yield was significantly lower in PB and PG as compared with PS. The study shows the great potential of dolichos as a promising intercrop that could be integrated into potato cropping systems without negatively affecting potato yield.

An inclusive and participatory approach to changing policies and practices for improved milk safety in Assam, northeast India

June 2018

Publication date: June 2018
Source:Global Food Security, Volume 17

Author(s): Johanna F. Lindahl, Ram Pratim Deka, David Melin, Anna Berg, Hanna Lundén, M. Lucila Lapar, Rainer Asse, Delia Grace

Animal products are highly nutritious, but also highly perishable. In India milk is an important source of animal protein, but problems with low quality of the milk, high degrees of adulterated milk on the market, high bacterial loads, and sometimes presence of zoonotic pathogens persist. Most dairy farmers in India are resource-poor small-holders, often with limited knowledge about the importance of food safety and hygiene. Milk quality problems including adulteration and bacterial contamination is common in the country.

This paper describes a training intervention for improved food safety in Guwahati, Assam, India, conducted in 2009–2013. The training was designed to be short, simple and customized, cheap to deliver, easily accessible, and accompanied by incentives to bring change in knowledge, attitude and practices (KAP). In 2014 three outcomes were assessed: changed KAP; milk production; and, mastitis prevalence. Selected food safety hazards were also assessed, although their management had not been included in training. We found evidence of improved KAP among trained farmers, 14% higher milk production, and a tendency towards less mastitis, but no effects on food safety hazard levels.

This study shows that a training intervention can have a medium-term impact, while the issue of food safety is more complex and cannot be assumed to automatically follow from even successful training.

Graphical abstract

Assessing the chemical and microbiological quality of farmed tilapia in Egyptian fresh fish markets

June 2018

Publication date: June 2018
Source:Global Food Security, Volume 17

Author(s): Mahmoud Eltholth, Kimberly Fornace, Delia Grace, Jonathan Rushton, Barbara Häsler

Fish make important contributions to food and nutrition security in low and middle income countries; however, they are also prone to contamination with a range of chemical and biological hazards. The presence of people's perception and health hazards has implications for consumer acceptability and hence the potential contribution of fish to nutrition and health. The aim of this study was to assess the chemical and microbiological quality of farmed tilapia in Egypt. We conducted a systematic literature review resulting in 38 papers meeting inclusion criteria. We also conducted a survey of seven hazardous chemicals in fish sampled from farms (300 samples from 100 farms) and of 5 biological hazards as well as total bacterial counts in fish sampled from retailers (300 samples from 100 retailers). The results showed that the level of contamination with heavy metals and pesticides was lower than the national and international permissible limits. On the other hand, level of contamination of a considerable proportion of samples with microbial pollutants was higher than the permissible limits. Results from the literature indicated that, the level of contamination of wild tilapia was higher than farmed tilapia, again in contradiction to common perceptions. Our results indicate that the risk of human exposure to heavy metals and pesticides via consumption of farmed tilapia is negligible compared to microbial hazards. These findings suggest that post-harvest contamination is the major health risk in the tilapia fish value chain and we make recommendations for addressing this.

Trade-offs in livestock development at farm level: Different actors with different objectives

June 2018

Publication date: June 2018
Source:Global Food Security, Volume 17

Author(s): Gareth Salmon, Nils Teufel, Isabelle Baltenweck, Mark van Wijk, Lieven Claessens, Karen Marshall

The livestock sector in Low and Middle Income Countries (LMICs) is evolving. In response to growing demand for livestock products, it is likely that smallholder production systems will experience varying forms of intensification. Associated decision making is made complex, not only with the intrinsic characteristics of livestock in LMICs (for instance as sources of income, assets, or social symbols), but also by diverse objectives of stakeholders and agricultural development paradigms. This paper discusses trade-offs that are likely to arise in the choice of livestock production systems; with a focus at household and farm level, economic gains, gender equity, environmental concerns, human nutrition and food safety are all considered. We begin by describing trajectories of livestock intensification in LMICs. Then potential trade-offs during such intensification are depicted; with examples concerning environmental, economic and social aspects. Recognising and understanding trade-offs is imperative; therefore we discuss decision making methods, the management of trade-offs and the balance between providing an average benefit for a population and the variation in benefit for individuals. Finally, a (partial) trade-off analysis is illustrated by use of a case study on household dairy cattle enterprises in Senegal. The discussion advocates for holistic approaches to agricultural development efforts, which include recognition of the multiple objectives and the associated trade-offs.

Production system and participatory identification of breeding objective traits for indigenous goat breeds of Uganda

June 2018

Publication date: June 2018
Source:Small Ruminant Research, Volume 163

Author(s): R.B. Onzima, S. Gizaw, D.R. Kugonza, J.A.M. van Arendonk, E. Kanis

The success of breeding programs in improving indigenous livestock breeds in Uganda has hitherto been limited due to lack of involvement of the key stakeholders. Thus, participatory approaches are being promoted for designing community based improvement programs. The aim of this study was to characterize the indigenous goat production systems and assess in a participatory manner farmer preferred traits for establishing breeding objectives for indigenous goat breeds in Uganda. 217 farm households representing three goat production systems (combinations of breed and region) were individually interviewed to assess the socio-economic characteristics of the regions and the preferences of the farmers for indigenous goat breeds. The three breed/region combinations were 78 households with the Small East African breed in Arua, 81 with the Mubende breed in Mubende and 58 with the Kigezi breed in Kabale. An index based approach was used to rank farmers’ choices of traits considered important for their production systems. Descriptive statistics show that overall the production systems were not significantly different in terms of the nature of the farms and the trait preferences of the farmers. The sale of live animals was considered a primary objective for keeping goats by farmers across all the production systems studied. Adaptation traits (disease resistance, heat tolerance and survival) were considered critical in the farmers’ preferred breed. Production traits (better prolificacy and faster growth rate) and marketing ease were other characteristics considered by the farmers. The results from the study are useful for designing farmer-participatory breeding programs for goats in the different production systems in Uganda.

Enhanced nitrogen cycling and N2O loss in water-saving ground cover rice production systems (GCRPS)

June 2018

Publication date: June 2018
Source:Soil Biology and Biochemistry, Volume 121

Author(s): Zhe Chen, Shan Lin, Zhisheng Yao, Xunhua Zheng, Silvia Gschwendtner, Michael Schloter, Meiju Liu, Yanan Zhang, Klaus Butterbach-Bahl, Michael Dannenmann

An alternative to conventional cultivation of rice on submerged paddy soil is the ground cover rice production system (GCRPS), in which soil is covered with a plastic film to reduce the use of irrigation water. However, reduced soil water, increased aeration and temperature under GCRPS could promote soil nitrogen (N) mineralizing, nitrifying and denitrifying microbes and thus enhance soil N turnover and environmental losses e.g., through emission of the potent greenhouse gas nitrous oxide (N2O). At two sites with paired GCRPS and conventional paddy fields in Central China, we followed the abundance and activity of N-mineralizers, nitrifiers, denitrifiers and N2-fixing microbes based on qPCR from DNA and RNA directly extracted from soil. With decreasing soil water during the growing season, GCRPS strongly increased N mineralization as illustrated by several fold increased transcript levels of chiA. Furthermore, GCRPS reduced the nifH transcripts (encoding for nitrogenase) by 38% to 70% but increased the qnorB transcripts by 160% and archaeal amoA (AOA) transcripts by one order of magnitude (encoding for nitric oxide reductase and ammonia monooxygenase). This indicated a higher potential for N losses due to decreased biological N2 fixation, increased N leaching and increased N2O emission in GCRPS. The latter was confirmed by increased in situ N2O emissions. In addition, the N2-fixing and denitrifying microbial community composition as measured by a community fingerprinting approach was strongly influenced by GCRPS cultivation. Hence, our study reveals the microbial mechanisms underlying the risks for increased N mineralization, nitrification and N2O emissions and decreased biological N fixation in GCRPS. However, analysis of topsoil N stocks provided evidence that at least under N fertilizer application, GCRPS might overall maintain soil N stocks. This might result from a GCRPS-induced increase in fertilizer N use efficiency, root development and C and N return via residues, which appear to outbalance the observed effects on nitrification, gaseous N losses and biological N fixation, thereby preventing a net loss of total soil N.

Soil water management practices (terraces) helped to mitigate the 2015 drought in Ethiopia

31 May 2018

Publication date: 31 May 2018
Source:Agricultural Water Management, Volume 204

Author(s): Frédéric Kosmowski

While the benefits of soil water management practices relative to soil erosion have been extensively documented, evidence regarding their effect on yields is inconclusive. Following a strong El-Niño, some regions of Ethiopia experienced major droughts during the 2015/16 agricultural season. Using the propensity scores method on a nationally representative survey in Ethiopia, this study investigates the effect of two widely adopted soil water management practices – terraces and contour bunds – on yields and assesses their potential to mitigate the effects of climate change. It is shown that at the national level, terraced plots have slightly lower yields than non-terraced plots. However, data support the hypothesis that terraced plots acted as a buffer against the 2015 Ethiopian drought, while contour bunds did not. This study provides evidence that terraces have the potential to help farmer deal with current climate risks. These results can inform the design of climate change adaptation policies and improve targeting of soil water management practices in Ethiopia.

Multiple uses of small reservoirs in crop-livestock agro-ecosystems of Volta basin: Implications for livestock management

31 May 2018

Publication date: 31 May 2018
Source:Agricultural Water Management, Volume 204

Author(s): Augustine A. Ayantunde, Olufunke. Cofie, Jennie Barron

Small reservoirs (SR) are structures that capture and store run-off from upstream catchment area for multiple uses including irrigation, fishing, livestock watering, domestic purpose and groundwater recharge. Though livestock watering is one of the major uses of small reservoirs in the Volta River basin of West Africa, there is limited information on how livestock management practices co-exist with other use of SRs. This study was carried out in a typical Sudano-Sahelian zone within the Volta basin in Burkina Faso, covering five reservoirs to 1) document multiple uses of the reservoirs with a focus on their utilization for livestock production. 2) identify proximate and long-term causes of livestock-related conflicts with regard to multiple uses of the water infrastructure and 3) explore strategies to manage the SR equitably for various uses. Adult males and boys accounted for at least 60% of the users of small reservoirs in our study. Livestock watering was done mainly by adult males. In addition to provision of water for livestock, small reservoirs also contributed to feed resources for animals by providing green forage (pasture grown on residual moisture) in the dry season which accounted for at least 5% of the total dry matter diet of cattle and small ruminant in late dry season. None of the 5 small reservoirs we studied was used for irrigated fodder production. Increased competitions over the use of small reservoirs, damage to irrigated crops by the animals, and increased number of livestock using the small reservoirs were ranked as the most important causes of conflict in the communities. Peaceful co-habitation of the use of the small reservoirs for irrigated vegetable production and livestock watering are essential for reduction of the incidence of conflict.

Plant Selection and Performance of Two Cattle Types and Camels on Semiarid Rangelands in Kenya

Available online 22 May 2018

Publication date: Available online 22 May 2018
Source:Rangeland Ecology & Management

Author(s): Paul T. Leparmarai, David M. Mwangi, Ilona Gluecks, Fredrick M. Mutie, Svenja Marquardt

Plant selection pattern and performance of lactating cattle and camels were compared on semiarid savanna rangelands in Kenya in the rainy season (RS) and a transition period (TP) between the RS and the main dry season. It was further evaluated whether supplementation with rumen-degradable protein (RDP) had an effect on these parameters. In both seasons, two cattle types (local ‘Pokot’ cattle and Guernsey × Boran crossbreds) and camels were used, with six females per treatment group (supplemented and nonsupplemented) each (n = 72 animals in total). The experimental periods consisted of 8–10 d of adaptation and 36–40 d of data and sample collection. The diet selected by the cattle types was similar and consisted almost exclusively of grasses. The camel diet consisted mainly of herbs and shrubs with higher contributions of woody plants in the TP than in the RS. Forage from woody plants overall made up a higher proportion of the diet, which was also reflected by a longer browsing time (overall and in the TP) of the supplemented camels compared with the nonsupplemented camels. This result indicates that supplementation of browsers like camels with RDP can be used to increase the intake of forage from woody plants rich in plant secondary compounds, which could be an effective measure for managing rangeland to limit bush encroachment. Overall, no seasonal differences in milk yield were found for the camels and Pokot cattle, but crossbreds had a lower yield in the TP compared with the RS. Overall, the cattle had higher milk fat content than the camels while the camels had slightly higher protein content. Supplementation had no effect on milk yield and composition. The results of diet selection and performance (milk yield) reflect the advantage of camels in arid rangelands.

Management intensity controls soil N2O fluxes in an Afromontane ecosystem

15 May 2018

Publication date: 15 May 2018
Source:Science of The Total Environment, Volume 624

Author(s): I. Wanyama, D.E. Pelster, C. Arias-Navarro, K. Butterbach-Bahl, L.V. Verchot, M.C. Rufino

Studies that quantify nitrous oxide (N2O) fluxes from African tropical forests and adjacent managed land uses are scarce. The expansion of smallholder agriculture and commercial agriculture into the Mau forest, the largest montane forest in Kenya, has caused large-scale land use change over the last decades. We measured annual soil N2O fluxes between August 2015 and July 2016 from natural forests and compared them to the N2O fluxes from land either managed by smallholder farmers for grazing and tea production, or commercial tea and eucalyptus plantations (n =18). Air samples from 5 pooled static chambers were collected between 8:00am and 11:30am and used within each plot to calculate the gas flux rates. Annual soil N2O fluxes ranged between 0.2 and 2.9kgNha⁻¹ yr⁻¹ at smallholder sites and 0.6–1.7kgNha⁻¹ yr⁻¹ at the commercial agriculture sites, with no difference between land uses (p =0.98 and p =0.18, respectively). There was marked variation within land uses and, in particular, within those managed by smallholder farmers where management was also highly variable. Plots receiving fertilizer applications and those with high densities of livestock showed the highest N2O fluxes (1.6±0.3kgN2O-Nha⁻¹ yr⁻¹, n =7) followed by natural forests (1.1±0.1kgN2O-Nha⁻¹ yr⁻¹, n =6); although these were not significantly different (p =0.19). Significantly lower fluxes (0.5±0.1kgNha⁻¹ yr⁻¹, p <0.01, n =5) were found on plots that received little or no inputs. Daily soil N2O flux rates were not correlated with concurrent measurements of water filled pore space (WFPS), soil temperature or inorganic nitrogen (IN) concentrations. However, IN intensity, a measure of exposure of soil microbes (in both time and magnitude) to IN concentrations was strongly correlated with annual soil N2O fluxes.

Graphical abstract

Genetic diversity and population structure of Theileria parva in South Sudan

May 2018

Publication date: May 2018
Source:Ticks and Tick-borne Diseases, Volume 9, Issue 4

Author(s): Diaeldin A. Salih, Joram M. Mwacharo, Roger Pelle, Moses N. Njahira, David O. Odongo, Mary N. Mbole-Kariuki, Wani L. Marcellino, Agol K. Malak, Henary Kiara, Abdel Rahim M. El Hussein, Richard P. Bishop, Robert A. Skilton

Theileria parva is a parasitic protozoan that causes East Coast fever (ECF), an economically important disease of cattle in eastern, central and southern Africa. In South Sudan, ECF is considered a major constraint for livestock development in regions where the disease is endemic. To obtain insights into the dynamics of T. parva in South Sudan, population genetic analysis was performed. Out of the 751 samples included in this study, 178 blood samples were positive for T. parva by species-specific PCR, were collected from cattle from four regions in South Sudan (Bor = 62; Juba = 45; Kajo keji = 41 and Yei = 30) were genotyped using 14 microsatellite markers spanning the four chromosomes. The T. parva Muguga strain was included in the study as a reference. Linkage disequilibrium was evident when populations from the four regions were treated as a single entity, but, when populations were analyzed separately, linkage disequilibrium was observed in Bor, Juba and Kajo keji. Juba region had a higher multiplicity of infection than the other three regions. Principal components analysis revealed a degree of sub-structure between isolates from each region, suggesting that populations are partially distinct, with genetic exchange and gene flow being limited between parasites in the four geographically separated populations studied. Panmixia was observed within individual populations. Overall T. parva population genetic analyses of four populations in South Sudan exhibited a low level of genetic exchange between the populations, but a high level of genetic diversity within each population.

Antibodies to in silico selected GPI-anchored Theileria parva proteins neutralize sporozoite infection in vitro

May 2018

Publication date: May 2018
Source:Veterinary Immunology and Immunopathology, Volume 199

Author(s): James Nyagwange, Vishvanath Nene, Stephen Mwalimu, Sonal Henson, Lucilla Steinaa, Benjamin Nzau, Edwin Tijhaar, Roger Pelle

East Coast fever (ECF) caused by Theileria parva kills cattle in East, Central and Southern Africa leading to significant economic losses. Vaccination is used as a control strategy against ECF and is presently dependent on deliberate infection with live sporozoites and simultaneous treatment with a long-acting oxytetracycline. Although effective, this method has serious limitations; the immunity is parasite strain specific and immunized cattle can become life-long asymptomatic carriers of the parasite, posing risk for the spread of the disease. In efforts to develop a subunit vaccine, the role of antibodies in the neutralization of T. parva sporozoites infection of host cells has been investigated and a circumsporozoite protein, p67, is able to induce such neutralizing antibodies. However, the p67 protein only protects a proportion of immunized cattle against T. parva challenge and such protection might be improved by inclusion of additional parasite antigens that neutralize sporozoite infection. In an attempt to identify such antigens, we searched the re-annotated T. parva genome for genes predicted to contain GPI anchor signals, since they are likely to be located on the cell surface, and expressed fragments of six of the selected genes in E. coli. The recombinant proteins were used to raise antisera in mice. Antisera to two proteins, TpMuguga_01g00876 and TpMuguga_01g00939, neutralized sporozoite infectivity to a high degree, while antisera to two additional proteins, TpMuguga_01g00095 and TpMuguga_04g00437, exhibited moderate neutralizing capacity. We conclude that these four antigens are potential vaccine candidates, which should be evaluated further in cattle.

Distribution and factors influencing chickpea wilt and root rot epidemics in Ethiopia

April 2018

Publication date: April 2018
Source:Crop Protection, Volume 106

Author(s): Sultan Mohammed Yimer, Seid Ahmed, Chemeda Fininsa, Negussie Tadesse, Aladdin Hamwieh, Douglas R. Cook

Chickpea is a major food legume crop in the mid-highlands of Ethiopia where its yield is negatively impacted by the wilt and root rot disease complex. The pathogens associated with WRR complex and their associations with biophysical factors have not been well understood in the past. We report here a survey of five major chickpea-growing regions covering 30 districts in the central and northern highlands of Ethiopia. The associations between disease parameters and biophysical factors were assessed using logistic regression analyses. Moreover, pathogens associated with wilt and root rot were identified, and their frequency of occurrence was determined. Mean percent wilt and root rot incidence and percent severity index were the highest in Gojam followed by Gondar and the lowest in Shoa. The major pathogens associated with infected roots were Fusarium oxysporum f. sp. ciceris, Fusarium solani, Rhizoctonia bataticola, Sclerotium rolfsii, and Rhizoctonia solani. The most frequently isolated pathogen was F. oxysporum f. sp. ciceris followed by R. solani. Moreover, significant (P < .001) associations between disease parameters and planting date and between weeding practice and soil and chickpea types were observed. High disease incidence and percent severity index showed high probability of association with planting date and chickpea types. Desi chickpea and chickpea that were planted early in the season had approximately 2 and 9 times greater probability of experiencing a high disease incidence and a 6–5 times greater probability of experiencing high wilt and root rot severity, respectively. High disease incidence and percent severity index were also correlated with weed infestation and planting on heavy black soils. Therefore, late planting, appropriate weeding, and the use of chickpea cultivars with a high level of resistance are important options to manage WRR complex.

Benefits, limitations and sustainability of soil and water conservation structures in Omo-Gibe basin, Southwest Ethiopia

April 2018

Publication date: April 2018
Source:Land Use Policy, Volume 73

Author(s): Kebede Wolka, Geert Sterk, Birhanu Biazin, Mesele Negash

Different types of soil and water conservation (SWC) structures were introduced to Ethiopia during the last four decades for abating water erosion and sustaining agricultural productivity. This study aimed to determine benefits, limitations and sustainability of SWC structures in the Toni and Bokole watersheds of the Omo Gibe basin. A household survey was conducted on a total of 201 households, which were selected by employing a multistage sampling procedure that covered six rural kebeles. ¹ 1

a smallest local administrative unit.

Moreover, six focus group discussions were conducted. The results revealed that more than 80% of respondents in Bokole watershed and all respondents in Toni watershed experienced moderate to severe soil erosion. Farmers were selective in accepting and implementing SWC structures depending on the local land characteristics. Stone bunds were widely implemented in Bokole watershed where rock fragments are abundant and Fanya juu and soil bunds were widely practiced in Toni watershed where rock fragments are not available. Owing to labor intensiveness of the SWC structures, more than 82% of respondents in Bokole and 54% in Toni perceived that labor shortage was a challenge for construction and maintenance. More than 74% of the adopter farmers were also concerned about the loss of cultivable land due to the construction of SWC structures. Number of cattle owned (p < 0.05) and having administrative responsibility in the kebele (p < 0.1) significantly and negatively influenced construction of the SWC structures in Bokole watershed. Runoff overtopping, livestock trampling and cultivation practices were mentioned as the causes of damages for the SWC structures in both watersheds. In Bokole watershed, 92% of the respondents indicated that they repaired the broken SWC structures to sustain their benefits. But 62% of respondents in Toni watershed did not repair. The effort of repairing the SWC structures was significantly (p < 0.05) and negatively influenced by farmland area in Bokole watershed and by education level in Toni watershed. The respondents’ preferences of SWC structures, rate of adoption, willingness to repair and factors affecting adoption and repairing were slightly different in Bokole watershed when compared with Toni watershed. Thus, we concluded that effective implementation and sustainability of SWC structures should critically consider the land users’ socio-economic and environmental intricacy.

Farmers’ knowledge and practices of potato disease management in Ethiopia

Available online 30 March 2018

Publication date: Available online 30 March 2018
Source:NJAS - Wageningen Journal of Life Sciences

Author(s): Shiferaw Tafesse, E. Damtew, B. van Mierlo, R. Lie, B. Lemaga, K. Sharma, C. Leeuwis, P.C. Struik

Effective management of potato diseases such as bacterial wilt and late blight depends to a large extent on farmers’ knowledge of the diseases as well as on the integration of recommended management methods in their daily practices. Late blight has continued to be a dominant potato disease for many decades in Ethiopia, whereas bacterial wilt has emerged more recently with a devastating impact on the country’s potato production systems. A survey of 261 randomly selected farmers was carried out in three major potato growing districts in the central highlands of Ethiopia to examine farmers’ knowledge and management practices of the two diseases, and to analyze the role of relevant knowledge in their practices. Considering their different characteristics, three groups of farmers were distinguished: producers of quality declared seed, producers of normal seed and producers of ware. The study shed light on the vital role the lack of knowledge about the diseases plays in shaping farmers’ daily potato production practices. Most farmers could recognize symptoms of the diseases on infected leaves and stems. However, they had very limited knowledge of the diseases including their causal agents, spreading mechanisms, and effective management methods, although they knew a little bit more about late blight than about bacterial wilt. Therefore, to effectively manage the diseases, farmers need to learn about the diseases and how to manage them in their local context applying a feasible combination of management options through a community-based approach. The effectivity of such an approach could be enhanced by stipulating operational standards in bylaws and through continuous monitoring of changes in farmers’ practices and environmental monitoring for disease occurrence by leveraging an interactive mobile-based platform.

Diagnosis of management of bacterial wilt and late blight in potato in Ethiopia: A systems thinking perspective

Available online 29 March 2018

Publication date: Available online 29 March 2018
Source:NJAS - Wageningen Journal of Life Sciences

Author(s): E. Damtew, Shiferaw Tafesse, R. Lie, B. van Mierlo, B. Lemaga, K. Sharma, P.C. Struik, C. Leeuwis

Potato is one of the most important food crops for smallholder farmers in the Ethiopian highlands. Diseases, particularly bacterial wilt (caused by Ralstonia solanacearum) and late blight (caused by Phytophthora infestans), are among the major constraints of potato production, despite continuous efforts to control them. Bacterial wilt and late blight are complex problems with multiple technical and institutional features, involving multiple actors with different perceptions and understanding, not only of the problem but also of possible solutions. Appreciating such complexity, this study adopted a systems thinking perspective. It aimed to explore actors’ understanding of the complex problem situation and its implication for the management of the diseases at a collective level. Using a multi-stakeholder workshop and in-depth interviews, a qualitative study was conducted with actors that are directly or indirectly involved in the management of the two diseases. Results showed that actors essentially overlooked key systemic problems in the management of the two diseases. This is mainly reflected in actors’ tendency to give event-level responses, shift responsibilities and engage in a mutual blaming to the problem of bacterial wilt and late blight. Lack of a preventive disease management culture, limited recognition of interdependencies among activities of actors, power inequalities, and top-down and linear approaches in information and knowledge sharing are identified as key structural problems that are underrated by the actors. We contend that the most appropriate way forward towards the management of both diseases is designing and implementing management strategies that, on the one hand, are preventive of disease epidemics, and, on the other hand, foster horizontal information sharing, learning and collective action among the local actors in the system. Digital platforms, particularly mobile-based technologies, can play a role in catalyzing new forms of information sharing, broader learning, and collaboration among farmers and local actors.

The role of infectious disease impact in informing decision-making for animal health management in aquaculture systems in Bangladesh

Available online 20 March 2018

Publication date: Available online 20 March 2018
Source:Preventive Veterinary Medicine

Author(s): Maria Garza, Chadag Vishnumurthy Mohan, Meezanur Rahman, Barbara Wieland, Barbara Häsler

The aquaculture sector in Bangladesh is an important employer and a significant source of foreign exchange. In addition, it contributes significantly to food security due to the role of fish in peoples’ diets, the most important source of protein and micronutrients. However, infectious diseases represent an important barrier to sector development due to economic losses and vulnerability of smallholders. The aim of this study was to gain an overview of the impact of infectious diseases in the aquaculture sector, and to assess the usefulness and use of impact studies in decision making for animal health management and biosecurity governance in Bangladesh. A review of scientific and grey literature on infectious disease impact in different aquaculture systems was conducted and their methodologies and findings summarised. Subsequently, interviews with 28 stakeholders from the private and public sector were conducted to enquire about decision-making structures in animal health management. The data were analysed using the framework method to allow the development of themes, by using the information, experiences and opinions inductively obtained from interviewees, deductively through the reviewed literature. Results showed a substantial socio-economic impact of infectious diseases. The numerous stakeholders involved in the decision-making process explained that key barriers to effective aquaculture health management were insufficient resources to investigate and tackle infectious aquatic animal diseases, a dearth of legislation and capacity for disease surveillance, a reliance on reactive response, and a lack of impact and evidence-based approaches for prioritising problem-solving, commonly based on anecdotal evidence. Furthermore, communication among the multiple stakeholders involved was reported to be weak. This complex situation requires a multi-level response, which should span from strengthening the knowledge of farmers and professionals in the field to the improvement of surveillance and diagnostic systems. Improved systems along with evidence on disease impact could inform the prioritisation of diseases and resource allocation for disease control in Bangladesh. Further, this evidence needs to be used to advise decisions to have a true value, for which establishing and strengthening communication pathways and processes is critical to make systematic use of the information and improve animal health management. In the light of future threats to Bangladesh such as climate change, increasing population density and demand for animal source foods, it is crucial to strengthen animal health management systems to reduce livelihoods vulnerability, food insecurity and the likelihood of disease emergence.

Xanthomonas Wilt of Banana (BXW) in Central Africa: Opportunities, challenges, and pathways for citizen science and ICT-based control and prevention strategies

Available online 17 March 2018

Publication date: Available online 17 March 2018
Source:NJAS - Wageningen Journal of Life Sciences

Author(s): Mariette McCampbell, Marc Schut, Inge Van den Bergh, Boudy van Schagen, Bernard Vanlauwe, Guy Blomme, Svetlana Gaidashova, Emmanuel Njukwe, Cees Leeuwis

Xanthomonas Wilt of Banana (BXW) is a complex problem in the African Great Lakes Region that is affecting the livelihoods of millions of smallholder farmers. Since the first disease reports from Uganda and the Democratic Republic of Congo in 2001, BXW has been studied widely. The majority of these studies focus on the technological or biophysical dimensions, while aspects and influence of socio-cultural, economic and institutional dimensions only recently started to gain attention. This paper provides an in-depth analysis of the broader BXW problem using a systems perspective, with the aim to add to the understanding about reasons for poor uptake of appropriate disease management practices, and limited ability to prevent rather than control BXW in the region. We comprehensively describe and analyse the various problem dimensions, and determine relations with data, information, knowledge, and connectivity. Building on this, the paper explores and discusses entry-points for the use of Information and Communication Technologies (ICT) and citizen science tools to better address BXW in banana production systems.

Land use and land cover dynamics in Dendi-Jeldu hilly-mountainous areas in the central Ethiopian highlands

15 March 2018

Publication date: 15 March 2018
Source:Geoderma, Volume 314

Author(s): Muluneh Minta, Kibebew Kibret, Peter Thorne, Tassew Nigussie, Lisanework Nigatu

The central Ethiopian highlands where most human and livestock populations concentrated have experienced a drastic change in land use and land cover (LULC) of the landscapes. This study was aimed to define the rate and pattern of LULC changes in Dendi-Jeldu hilly-mountainous areas in the central Ethiopia. Aerial photographs of years 1957 and 1995, and Landsat images taken at 1995 and 2014 were used to analyze the historical land use and land cover (LULC) changes. The study covered an area of about 438km². The analysis extracted from these remote sensing data revealed that, in 1957, the dominant LULCs were pastureland, cultivated land (cropland) and forestland covering 49, 25 and 20% of the total area, respectively. Remarkable LULC change dominated by cultivated land expansion (now covering 68% of the total area), however, claimed vast areas under pastureland (main), forestland and woodland. Deforestation in particular, would have been greater if Chilimo forest (remnant afro-montane forest) was not under state control. Plantation forestry exclusively dominated by eucalyptus species also showed substantial expansion into pastureland in the period between 1957 and 1995, and cultivated land between 1995 and 2014. In the period 1957 to 2014 cultivated land, plantation land and settlement were increased by 170%, 13,674% and 172% respectively, while pastureland, forestland and woodland declined by 67%, 73% and 100%, respectively. Change from natural habitat (pastureland, forestland and woodland) to other land uses (cultivated, plantation and settlement lands) is likely to have a large impact on biodiversity, land degradation and beyond.

Immune parameters to p67C antigen adjuvanted with ISA206VG correlate with protection against East Coast fever

7 March 2018

Publication date: 7 March 2018
Source:Vaccine, Volume 36, Issue 11

Author(s): Anna Lacasta, Stephen Mwalimu, Elisabeth Kibwana, Rosemary Saya, Elias Awino, Thomas Njoroge, Jane Poole, Nicholas Ndiwa, Roger Pelle, Vishvanath Nene, Lucilla Steinaa

East Coast fever (ECF) is a lymphoproliferative disease caused by the tick-transmitted protozoan parasite Theileria parva. ECF is one of the most serious cattle tick-borne diseases in Sub-Saharan Africa. We have previously demonstrated that three doses of the C-terminal part of the sporozoite protein p67 (p67C) adjuvanted with ISA206VG confers partial protection against ECF at a herd level. We have tested the efficacy of two doses of this experimental vaccine, as reducing the vaccination regimen would facilitate its deployment in the field. We reconfirm that three antigen doses gave a significant level of protection to severe disease (46%, ECF score < 6) when compared with the control group, while two doses did not (23%). Animals receiving three doses of p67C developed higher antibody titers and CD4⁺ T-cell proliferation indices, than those which received two doses. A new panel of immune parameters were tested in order to identify factors correlating with protection: CD4⁺ proliferation index, total IgG, IgG1, IgG2 and IgM half maximal titers and neutralization capacity of the sera with and without complement. We show that some of the cellular and humoral immune responses provide preliminary correlates of protection.

A new approach for improving emission factors for enteric methane emissions of cattle in smallholder systems of East Africa – Results for Nyando, Western Kenya

March 2018

Publication date: March 2018
Source:Agricultural Systems, Volume 161

Author(s): J.P. Goopy, A.A. Onyango, U. Dickhoefer, K. Butterbach-Bahl

In Africa, the agricultural sector is the largest sector of the domestic economy, and livestock, are a crucial component of agriculture, accounting for ~45% of the Kenyan agricultural GDP and >70% of African agricultural greenhouse gas (GHG) emissions. Accurate estimates of GHG emissions from livestock are required for inventory purposes and to assess the efficacy of mitigation measures, but most estimates rely on TIER I (default) IPCC protocols with major uncertainties coming from the IPCC methodology itself. Tier II estimates represent a significant improvement over the default methodology, however in less developed economies the required information is lacking or of uncertain reliability. In this study we developed an alternative methodology based on animal energy requirements derived from field measurements of live weight, live weight change, milk production and locomotion to estimate intake. Using on-farm data, we analysed feed samples to produce estimates of digestibility by season and region, then and used these data to estimate daily methane production by season, area and class of animal to produce new emission factors (EF) for annual enteric CH4 production. Mean Dry Matter Digestibility of the feed basket was in the range of 58–64%, depending on region and season (around 10% greater than TIER I estimates). EFs were substantially lower for adolescent and adult male (30.1, 35.9 versus 49kg CH4) and for adolescent and adult female (23.0, 28.3 versus 41kg), but not calves (15.7 versus 16kg) than those given for “other” African cattle in IPCC (Tier I) estimates. It is stressed that this study is the first of its kind for Sub-Sharan Africa relying on animal measurements, but should not automatically be extrapolated outside of its geographic range. It does however, point out the need for further measurements, and highlights the value of using a robust methodology which does not rely on the (often invalid) assumption of ad libitum intake in systems where intake is known or likely to be restricted.

Corrigendum to “Targeting, out-scaling and prioritising climate-smart interventions in agricultural systems: Lessons from applying a generic framework to the livestock sector in sub-Saharan Africa” [Agric. Syst. 2017 Feb; 151: 153–162]

March 2018

Publication date: March 2018
Source:Agricultural Systems, Volume 161

Author(s): An Notenbaert, Catherine Pfeifer, Silvia Silvestri, Mario Herrero

Grazing systems expansion and intensification: Drivers, dynamics, and trade-offs

March 2018

Publication date: March 2018
Source:Global Food Security, Volume 16

Author(s): Cécile M. Godde, Tara Garnett, Philip K. Thornton, Andrew J. Ash, Mario Herrero

Grazing systems dynamics are driven by a complex combination of socio-economic, political and environmental contexts. Although the drivers and dynamics can be highly location-specific, we focus on describing global trends as well as trends by agro-ecological, socio-economic and political contexts. Global grasslands have expanded in area over the last decades. A decreasing trend has however been observed since the 21st century. Grazing systems’ management has also intensified. While these dynamics can have socio-economic and environmental benefits, they have often led to unsustainable systems, exemplified by deforestation and land degradation. Opportunities for land expansion without damaging forests and natural ecosystems are increasingly limited around the world and future increases in grazing systems production will need to mainly come from increases in productivity per animal and per unit area. We highlight some priority research areas and issues for policy makers to consider to help the movement towards more sustainable systems.

Characterization of the Theileria parva sporozoite proteome

March 2018

Publication date: March 2018
Source:International Journal for Parasitology, Volume 48, Issues 3–4

Author(s): James Nyagwange, Edwin Tijhaar, Nicola Ternette, Fredrick Mobegi, Kyle Tretina, Joana C. Silva, Roger Pelle, Vishvanath Nene

East Coast fever is a lymphoproliferative disease caused by the tick-borne protozoan parasite Theileria parva. The sporozoite stage of this parasite, harboured and released from the salivary glands of the tick Rhipicephalus appendiculatus during feeding, invades and establishes infection in bovine lymphocytes. Blocking this initial stage of invasion presents a promising vaccine strategy for control of East Coast fever and can in part be achieved by targeting the major sporozoite surface protein p67. To support research on the biology of T. parva and the identification of additional candidate vaccine antigens, we report on the sporozoite proteome as defined by LC–MS/MS analysis. In total, 4780 proteins were identified in an enriched preparation of sporozoites. Of these, 2007 were identified as T. parva proteins, representing close to 50% of the total predicted parasite proteome. The remaining 2773 proteins were derived from the tick vector. The identified sporozoite proteins include a set of known T. parva antigens targeted by antibodies and cytotoxic T cells from cattle that are immune to East Coast fever. We also identified proteins predicted to be orthologs of Plasmodium falciparum sporozoite surface molecules and invasion organelle proteins, and proteins that may contribute to the phenomenon of bovine lymphocyte transformation. Overall, these data establish a protein expression profile of T. parva sporozoites as an important starting point for further study of a parasitic species which has considerable agricultural impact.

Graphical abstract

Ancient diversity and geographical sub-structuring in African buffalo Theileria parva populations revealed through metagenetic analysis of antigen-encoding loci

March 2018

Publication date: March 2018
Source:International Journal for Parasitology, Volume 48, Issues 3–4

Author(s): Johanneke D. Hemmink, Tatjana Sitt, Roger Pelle, Lin-Mari de Klerk-Lorist, Brian Shiels, Philip G. Toye, W. Ivan Morrison, William Weir

An infection and treatment protocol involving infection with a mixture of three parasite isolates and simultaneous treatment with oxytetracycline is currently used to vaccinate cattle against Theileria parva. While vaccination results in high levels of protection in some regions, little or no protection is observed in areas where animals are challenged predominantly by parasites of buffalo origin. A previous study involving sequencing of two antigen-encoding genes from a series of parasite isolates indicated that this is associated with greater antigenic diversity in buffalo-derived T. parva. The current study set out to extend these analyses by applying high-throughput sequencing to ex vivo samples from naturally infected buffalo to determine the extent of diversity in a set of antigen-encoding genes. Samples from two populations of buffalo, one in Kenya and the other in South Africa, were examined to investigate the effect of geographical distance on the nature of sequence diversity. The results revealed a number of significant findings. First, there was a variable degree of nucleotide sequence diversity in all gene segments examined, with the percentage of polymorphic nucleotides ranging from 10% to 69%. Second, large numbers of allelic variants of each gene were found in individual animals, indicating multiple infection events. Third, despite the observed diversity in nucleotide sequences, several of the gene products had highly conserved amino acid sequences, and thus represent potential candidates for vaccine development. Fourth, although compelling evidence for population differentiation between the Kenyan and South African T. parva parasites was identified, analysis of molecular variance for each gene revealed that the majority of the underlying nucleotide sequence polymorphism was common to both areas, indicating that much of this aspect of genetic variation in the parasite population arose prior to geographic separation.

Graphical abstract

African swine fever control and market integration in Ugandan peri-urban smallholder pig value chains: An ex-ante impact assessment of interventions and their interaction

1 March 2018

Publication date: 1 March 2018
Source:Preventive Veterinary Medicine, Volume 151

Author(s): Emily Ouma, Michel Dione, Rosemirta Birungi, Peter Lule, Lawrence Mayega, Kanar Dizyee

Pig production in peri-urban smallholder value chains in Uganda is severely constrained by impact of disease, particularly African swine fever (ASF), and the economic consequences of an inefficient pig value chain. Interventions in the form of biosecurity to control ASF disease outbreaks and pig business hub models to better link smallholder farmers to pig markets have the potential to address the constraints. However, there is a dearth of evidence of the effects of the interventions on performance and distribution of outcomes along the pig value chain. An ex-ante impact assessment utilising System Dynamics model was used to assess the impact of the interventions in peri-urban pig value chains in Masaka district. The results showed that although implementation of biosecurity interventions results in reduction of ASF outbreaks, it also leads to a 6.3% reduction in farmer profit margins per year but more than 7% increase in other value chain actors’ margins. The pig business hub intervention alone results in positive margins for all value chain actors but minimal reduction in ASF outbreaks. When biosecurity and the pig business hub interventions are implemented together, the interaction effects of the interventions result in positive outcomes for both the control of ASF and improvement in farmers’ margins. Farmers may therefore be unwilling to adopt biosecurity practices if implemented alone to control ASF outbreaks unless there is a corresponding financial incentive to compensate for the high costs. This has implications for policy or developing institutions to facilitate cost sharing arrangement among chain actors and/or third party subsidy to provide incentives for producers to adopt biosecurity measures.

Conversion of natural forest results in a significant degradation of soil hydraulic properties in the highlands of Kenya

March 2018

Publication date: March 2018
Source:Soil and Tillage Research, Volume 176

Author(s): S.O. Owuor, K. Butterbach-Bahl, A.C. Guzha, S. Jacobs, L. Merbold, M.C. Rufino, D.E. Pelster, E. Díaz-Pinés, L. Breuer

Land use change, especially conversion of native forests can have large impacts on water resources. Large scale conversion of native forests to agricultural land has occurred in the last few decades in the Mau Forest region. To quantify and understand landscape hydrologic responses, this study aimed at evaluating the effects of land use on soil infiltration, saturated hydraulic conductivity, bulk density, sorptivity, and soil moisture retention. A total of 136 plots representing five different land uses (native forest: n=39, forest plantations: n=14, tea plantations: n=24, croplands: n=23 and pasture: n=36) were sampled in three catchments with similar parental material in the Mau Forest region, Western Kenya. Native forest topsoils (0–5cm) had a bulk density of 1.0±0.2gcm⁻³ which was similar to values found for topsoils of forest plantations (1.1±0.2gcm⁻³), but significantly lower than topsoils from croplands (1.4±0.2gcm⁻³), tea plantation (1.3±0.3gcm⁻³) and pastures (1.4±0.2gcm⁻³). Similarly, soil infiltration rates were higher in native forest (76.1±50cmh⁻¹) and in forest plantation (60.2±47.9cmh⁻¹) than in croplands (40.5±21.5cmh^‐1), tea plantations (43.3±29.2cmh⁻¹) and pastures (13.8±14.6cmh⁻¹). Native forest had the highest topsoil organic carbon contents (8.11±2.42%) and field capacity (0.62 ±0.12cm³ cm⁻³), while the highest permanent wilting point was recorded for pasture soils (mean of 0.41±0.06cmcm⁻³). The highest plant available water capacity was recorded for soils in native forest (mean of 0.27±0.14cmcm⁻³). Our study indicates that land use changes result in a significant degradation of soil hydraulic properties, which has likely resulted in changes of the regional water balance. Given the magnitude in which managed land use types have changed infiltration rates in our study area, we conclude that changes in land use types occurring in our study region in the last decades have already affected the hydrological regime of the landscapes and the compositions of flow components. The reduction in infiltration and hydraulic conductivity could result in increased surface run-off, erosion and frequency of flooding events.

Soil nitrous oxide emissions from agricultural soils in Canada: Exploring relationships with soil, crop and climatic variables

15 February 2018

Publication date: 15 February 2018
Source:Agriculture, Ecosystems & Environment, Volume 254

Author(s): Philippe Rochette, Chang Liang, David Pelster, Onil Bergeron, Reynald Lemke, Roland Kroebel, Douglas MacDonald, Weikai Yan, Corey Flemming

National scale emissions of nitrous oxide (N2O) from agricultural soils are often estimated using a unique fertilizer-induced emission factor (EF); thereby neglecting how factors other than nitrogen input could impact emissions. In the present study, we compiled soil N2O flux data collected since 1990 on agricultural soils in Canada, to identify key soil and climate factors, and management practices that explain variations in N2O emissions and in EF. Stepwise regression analysis showed that the growing season precipitation was the most important factor impacting N2O emissions, and that cumulative N2O fluxes and EFs could be predicted using equations (R² from 0.68 to 0.85) including two to five of the following variables: growing season precipitation, ratio of growing season precipitation to potential evapotranspiration, mean annual air temperature, crop type (annual or perennial), soil pH, texture and organic carbon content. We conclude that N2O EFs could be effectively stratified based on growing season precipitation, soil texture (coarse, medium and fine), type of N (synthetic and organic), and crop type (perennial and annual). We propose EFs that account for the dominant factors that modulate the nitrogen fertilizer-induced emissions and should improve regional and national estimates in Canada. They may also provide useful information for guiding the development of soil N2O emission quantification in other countries.

The Lancet Countdown on health and climate change: from 25 years of inaction to a global transformation for public health

10–16 February 2018

Publication date: 10–16 February 2018
Source:The Lancet, Volume 391, Issue 10120

Author(s): Nick Watts, Markus Amann, Sonja Ayeb-Karlsson, Kristine Belesova, Timothy Bouley, Maxwell Boykoff, Peter Byass, Wenjia Cai, Diarmid Campbell-Lendrum, Jonathan Chambers, Peter M Cox, Meaghan Daly, Niheer Dasandi, Michael Davies, Michael Depledge, Anneliese Depoux, Paula Dominguez-Salas, Paul Drummond, Paul Ekins, Antoine Flahault, Howard Frumkin, Lucien Georgeson, Mostafa Ghanei, Delia Grace, Hilary Graham, Rébecca Grojsman, Andy Haines, Ian Hamilton, Stella Hartinger, Anne Johnson, Ilan Kelman, Gregor Kiesewetter, Dominic Kniveton, Lu Liang, Melissa Lott, Robert Lowe, Georgina Mace, Maquins Odhiambo Sewe, Mark Maslin, Slava Mikhaylov, James Milner, Ali Mohammad Latifi, Maziar Moradi-Lakeh, Karyn Morrissey, Kris Murray, Tara Neville, Maria Nilsson, Tadj Oreszczyn, Fereidoon Owfi, David Pencheon, Steve Pye, Mahnaz Rabbaniha, Elizabeth Robinson, Joacim Rocklöv, Stefanie Schütte, Joy Shumake-Guillemot, Rebecca Steinbach, Meisam Tabatabaei, Nicola Wheeler, Paul Wilkinson, Peng Gong, Hugh Montgomery, Anthony Costello