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Crop residue allocation to livestock feed, soil improvement and other uses along a productivity gradient in Eastern Africa
(Journal Article, 2016-07) Duncan, Alan J.; Bachewe, Fantu Nisrane; Mekonnen, Kindu; Valbuena, Diego; Rachier, Gideon O.; Lule, D.; Bahta, Mesfin; Erenstein, Olaf
Crop residues are a key livelihood resource in smallholder mixed crop-livestock systems in Sub-Saharan Africa. With expansion of arable land and resultant decline in grazing resources, crop residues are becoming an increasingly important component of livestock feeds. This demand for livestock feeds has implications for the long-term sustainability of such systems since failure to return biomass to soils has implications for soil quality and the capacity of soils to support long-term productivity. Biomass allocation patterns are likely to vary with overall level of productivity and hence availability. In this study we used a household survey to quantify crop residue allocation patterns across a gradient of productivity in Eastern Africa focusing on two sites in Ethiopia and one in Kenya. We assessed the underlying determinants of crop residue allocation patterns with a view to understanding how productivity increases through intensification will influence biomass allocation in Eastern Africa and how livelihood and natural resource management objectives could be optimized. Results showed that farmers strongly favour allocation of residues to livestock feeding but that allocation to soil increases along the productivity gradient. This reduced feeding to livestock and increased allocation to soil fertility is associated with smaller farm sizes leading to reduced animal traction needs for tillage, increased overall livestock productivity, increased use of inputs and a reduced reliance on farm-based activities in overall livelihood strategies. The implications of these trends are that productivity increases in smallholder systems are likely to reduce pressure on biomass in the long term and that measures that enhance the prospects for farmers to intensify their production systems are likely to increase soil health and sustainability objectives in general. A key conclusion of the work is that intensification of livestock production could reduce crop residue allocation to soils with long term implications for soil productivity.
Participatory analysis of vulnerability to drought in three agro-pastoral communities in the West African Sahel
(Journal Article, 2015-12) Ayantunde, Augustine A.; Turner, M.D.; Kalilou, A.
Drought is one of the major climatic hazards impacting on the various sectors including crop and livestock in the West African Sahel. Pastoral and agro-pastoral communities in the region are regularly affected by drought, with vulnerability differing with gender, age, wealth status (access to cropland and livestock endowment), geographic location, social networks, and previous exposure to drought. Effective interventions require regular monitoring of vulnerability to drought, for which various quantitative and qualitative approaches exist. Qualitative assessments of vulnerability rely on participatory approaches with emphasis on involvement of the local communities in the analysis of their vulnerability to climate-induced stresses. In this study, we used a participatory approach to assess the vulnerability of three agro-pastoral communities in Niger to drought. The specific objective of this study was to assess the strength and limitation of a participatory vulnerability approach using a case study. According to the respondents in all the study sites, the incidence of drought has become more frequent in the last three decades compared to previous decades (before 1970). The impacts of drought on livelihoods according to the participants included food shortage, famine, forced sale of livestock to buy grain, decimation of livestock herds, and massive exploitation of woody plant species. The main weakness of participatory vulnerability assessments is the scalability of findings, as they are often location-specific. Therefore, participatory assessment should be complemented with more rigorous quantitative approaches to enhance applicability of the results to other locations with similar contexts.
Assessing the potential of dual-purpose maize in southern Africa: A multi-level approach
(Journal Article, 2013-09) Homann-Kee Tui, Sabine; Blümmel, Michael; Valbuena, Diego; Chirima, A.; Masikati, Patricia; Rooyen, Andre F. van; Kassie, Girma T.
This paper explores the potential and challenges of increasing production of food and feed on existing maize fields in mixed crop-livestock systems in the semi-arid areas of southern Africa. It integrates results from different sources of data and analysis: 1. Spatial stratification using secondary data for GIS layers: Maize mega-environments combined with recommendation domains for dual-purpose maize were constructed for Malawi, Mozambique and Zimbabwe, stratifying the countries by demand factors (livestock densities and human population densities) and feed availability. Relative biomass contributions to feed resources from rangelands were compared to those from croplands to explore the usefulness of global datasets for feed supply estimations. 2. Verification through farming systems analysis: the potential demand for maize residues as feed (maize cropping patterns, maize yields and uses, feed deficits) was compared at contrasting sites, based on household survey data collected on 480 households in 2010. 3. Maize cultivar analysis: Genotypic variability of maize cultivars was compared to evaluate the potential contribution (stover quantity and quality) of dual-purpose maize to reduce feed deficits. The study results illustrate high spatial variability in the demand for and supply of maize residues. Northern Malawi is characterized by high livestock density, high human population density and high feed availability. Farmers achieve maize yields of more than 2 t/ha resulting in surplus of residues. Although livestock is important, southwest Zimbabwe has low livestock densities, low human populations and low feed availability; farming systems are more integrated and farmers make greater use of maize residues to address feed shortages. Central Mozambique also has low cattle densities, low human populations and low feed availability. More rangelands are available but maize yields are very low and livestock face severe feed shortages. The investigation of 14 advanced CIMMYT maize landraces cultivars and 15 advanced hybrids revealed significant variations in grain and stover yield and fodder quality traits. Where livestock densities are high and alternative feed resources are insufficient, maize cultivars with superior residue yield and fodder quality can have substantial impact on livestock productivity. Cultivars at the higher end of the quality range can provide sufficient energy for providing livestock maintenance requirements and support about 200 g of live weight gain daily. Maize cultivars can be targeted according to primary constraints of demand domains for either stover quantity or stover fodder quality and the paper proposes an approach for this based on voluntary feed intake estimates for maize stover.
Conservation agriculture in mixed crop-livestock systems: Scoping crop residue trade-offs in Sub-Saharan Africa and South Asia
(Journal Article, 2012-06) Valbuena, Diego; Erenstein, Olaf; Homann-Kee Tui, Sabine; Abdoulaye, Tahirou; Claessens, Lieven; Duncan, Alan J.; Gerard, Bruno G.; Rufino, Mariana C.; Teufel, Nils; Rooyen, Andre F. van; Wijk, Mark T. van
Conservation Agriculture (CA) is being advocated to enhance soil health and sustain long term crop productivity in the developing world. One of CA's key principles is the maintenance of soil cover often by retaining a proportion of crop residues on the field as mulch. Yet smallholder crop–livestock systems across Africa and Asia face trade-offs among various options for crop residue use. Knowledge of the potential trade-offs of leaving more residues as mulch is only partial and the objective of this research is to address some of these knowledge gaps by assessing the trade-offs in contrasting settings with mixed crop–livestock systems. The paper draws from village surveys in 12 sites in 9 different countries across Sub-Sahara Africa and South Asia. Sites were clustered into 3 groups along the combined population and livestock density gradients to assess current crop residue management practices and explore potential challenges to adopting mulching practices in different circumstances. Results show that although high-density sites face higher potential pressure on resources on an area basis, biomass production tends to be more substantial in these sites covering demands for livestock feed and allowing part of the residues to be used as mulch. In medium-density sites, although population and livestock densities are relatively lower, biomass is scarce and pressure on land and feed are high, increasing the pressure on crop residues and their opportunity cost as mulch. In low-density areas, population and livestock densities are relatively low and communal feed and fuel resources exist, resulting in lower potential pressure on residues on an area basis. Yet, biomass production is low and farmers largely rely on crop residues to feed livestock during the long dry season, implying substantial opportunity costs to their use as mulch. Despite its potential benefit for smallholder farmers across the density gradient, the introduction of CA-based mulching practices appears potentially easier in sites where biomass production is high enough to fulfil existing demands for feed and fuel. In sites with relatively high feed and fuel pressure, the eventual introduction of CA needs complementary research and development efforts to increase biomass production and/or develop alternative sources to alleviate the opportunity costs of leaving some crop residues as mulch.
Integrating crops and livestock in subtropical agricultural systems
(Journal Article, 2012-03-30) Wright, Iain A.; Tarawali, Shirley A.; Blümmel, Michael; Gerard, Bruno G.; Teufel, Nils; Herrero, Mario
As the demand for livestock products increases, and is expected to continue to increase over the next few decades, especially in developing countries, smallholder mixed systems are becoming more intensive. However, with limited land and water resources and concern about the environmental impact of agricultural practices and climate change, the challenge is to find ways of increasing productivity that do not compromise household food security, but rather increase incomes equitably and sustain or enhance the natural resource base. In developed countries there has been increased specialisation of crop and livestock production. In contrast, the majority of livestock in developing countries is kept in mixed crop/livestock systems. Crops (cereal grains and pulses) and crop residues provide the basis of the diet for animals, e.g. cereal straw fed to dairy cattle or sweet potato vines fed to pigs. Animal manure can provide significant nutrient inputs to crops. Water productivity is higher in mixed crop/livestock systems compared with growing crops alone. Mixed systems allow for a more flexible and profitable use of family labour where employment opportunities are limited. They also spread risks across several enterprises, a consideration in smallholder systems that may become even more important under certain climate change scenarios. Integrated crop/livestock systems can play a significant role in improving global food security but will require appropriate technological developments, institutional arrangements and supportive policy environments if they are to fulfil that potential in the coming decades.
Use of the APSIM model in long term simulation to support decision making regarding nitrogen management for pearl millet in the Sahel
(Journal Article, 2010-02) Akponikpè, Pierre B.I.; Gerard, Bruno G.; Michels, K.; Bielders, Charles L.
Soil fertility and climate risks are hampering crop production in the Sahelian region. Because experiments with only a few fertility management options on a limited number of sites and years cannot fully capture the complex and highly non-linear soil–climate–crop interactions, crop growth simulation models may suitably complement experimental research to support decision making regarding soil fertility and water management. By means of a long term (23 years) scenario analysis using the Agricultural Production Systems Simulator (APSIM) model, this study investigates millet response to N in view of establishing N recommendations better adapted to subsistence small-holder millet farming in the Sahel. Prior to this, the APSIM model was tested on a rainfed randomized complete block experiment carried out during the 1994 and 1995 cropping seasons, having contrasting rainfall conditions. The experiment combined, at three levels each, the application of cattle manure (300, 900 and 2700 kg ha−1), millet residue (300, 900 and 2700 kg ha−1) and mineral fertilizer (unfertilized control, 15 kg N ha−1 + 4.4 kg P ha−1 and 45 kg N ha−1 + 13.1 kg P ha−1) at ICRISAT Sahelian Center, Niger. The model suitably predicted plant available water PAW and the simulated water and nitrogen stress were in agreement with measurement (water) and expectation (N) regarding the fertilizer and rainfall conditions of the experiment. APSIM simulations were in satisfactory agreement with the observed crop growth except for the highest crop residue application rates (>900 kg ha−1). For biomass and grain yield, the model performance was relatively good in 1994 but biomass yields were slightly overpredicted in 1995. The model was able to adequately reproduce the average trend of millet grain yield response to N inputs from manure and fertilizer, and to predict the overall observed higher grain yield in 1995 compared to 1994, despite the better rainfall in 1994. The 23-year, long term scenario analysis combining different application rates of cattle manure, millet residue and mineral fertilizer, showed that moderate N application (15 kg N ha−1) improves both the long term average and the minimum yearly guaranteed yield without increasing inter-annual variability compared to no N input. Although it does imply a lower average yield than at 30 kg N ha−1, the application of 15 kg N ha−1 appears more appropriate for small-holder, subsistence farmers than the usual 30 kg N ha−1 recommendation as it guarantees higher minimum yield in worst years, thereby reducing their vulnerability.
Simulating rural environmentally and socio-economically constrained multi-activity and multi-decision societies in a low-data context: A challenge through empirical agent-based modeling
(Journal Article, 2010-03-31) Saqalli, M.; Gerard, Bruno G.; Bielders, Charles L.; Defourny, Pierre
Development issues in developing countries belong to complex situations where society and environment are intricate. However, such sites lack the necessary amount of reliable, checkable data and information, while these very constraining factors determine the populations' evolutions, such as villagers living in Sahelian environments. Beyond a game-theory model that leads to a premature selection of the relevant variables, we build an individual-centered, empirical, KIDS-oriented (Keep It Descriptive & Simple), and multidisciplinary agent-based model focusing on the villagers\' differential accesses to economic and production activities according to social rules and norms, mainly driven by social criteria from which gender and rank within the family are the most important, as they were observed and registered during individual interviews. The purpose of the work is to build a valid and robust model that overcome this lack of data by building a individual specific system of behaviour rules conditioning these differential accesses showing the long-term catalytic effects of small changes of social rules. The model-building methodology is thereby crucial: the interviewing process provided the behaviour rules and criteria while the context, i.e. the economic, demographic and agro-ecological environment is described following published or unpublished literature. Thanks to a sensitivity analysis on several selected parameters, the model appears fairly robust and sensitive enough. The confidence building simulation outputs reasonably reproduces the dynamics of local situations and is consistent with three authors having investigated in our site. Thanks to its empirical approach and its balanced conception between sociology and agro-ecology at the relevant scale, i.e. the individual tied to social relations, limitations and obligations and connected with his/her biophysical and economic environment, the model can be considered as an efficient "trend provider" but not an absolute "figure provider" for simulating rural societies of the Nigrien Sahel and testing scenarios on the same context. Such ABMs can be a useful interface to analyze social stakes in development projects.
Spatio-temporal dynamics of genetic diversity in Sorghum bicolor in Niger
(Journal Article, 2010-05) Deu, M.; Sagnard, F.; Chantereau, J.; Calatayud, C.; Vigouroux, Yves; Pham, J.L.; Mariac, C.; Kapran, I.; Mamadou, A.; Gerard, Bruno G.; Ndjeunga, J.; Bezançon, G.
The dynamics of crop genetic diversity need to be assessed to draw up monitoring and conservation priorities. However, few surveys have been conducted in centres of diversity. Sub-Saharan Africa is the centre of origin of sorghum. Most Sahel countries have been faced with major human, environmental and social changes in recent decades, which are suspected to cause genetic erosion. Sorghum is the second staple cereal in Niger, a centre of diversity for this crop. Niger was submitted to recurrent drought period and to major social changes during these last decades. We report here on a spatio-temporal analysis of sorghum genetic diversity, conducted in 71 villages covering the rainfall gradient and range of agro-ecological conditions in Niger’s agricultural areas. We used 28 microsatellite markers and applied spatial and genetic clustering methods to investigate change in genetic diversity over a 26-year period (1976–2003). Global genetic differentiation between the two collections was very low (F st = 0.0025). Most of the spatial clusters presented no major differentiation, as measured by F st, and showed stability or an increase in allelic richness, except for two of them located in eastern Niger. The genetic clusters identified by Bayesian analysis did not show a major change between the two collections in the distribution of accessions between them or in their spatial location. These results suggest that farmers’ management has globally preserved sorghum genetic diversity in Niger.
Empirical characterisation of agent behaviours in socio-ecological systems
(Journal Article, 2011-07) Smajgl, A.; Brown, D.G.; Valbuena, Diego; Huigen, M.G.A.
Agent-based modelling has become an important tool to investigate socio-ecological processes. Its use is partially driven by increasing demand from decision makers to provide support for understanding the potential implications of decisions in complex situations. While one of the advantages of agent-based modelling is the ability to simulate the implications of human decision-making processes explicitly, methods for providing empirical support for the representation of the behaviour of human agents have not been structured systematically. This paper develops a framework for the parameterisation of human behaviour in agent-based models and develops twelve distinct sequences for the characterisation and parameterisation of human behaviours. Examples are provided to illustrate the most important sequences. This framework is a first step towards a guide for parameterisation of human behaviour in ABM. A structured discussion within the agent-based community is needed to achieve a more definitive guideline.
Targeting rural development interventions: Empirical agent-based modeling in Nigerien villages
(Journal Article, 2011-04) Saqalli, M.; Gerard, Bruno G.; Bielders, Charles L.; Defourny, Pierre
The aim of this article is to analyze the impact of development interventions on the population of three Nigerien villages that differ in terms of their agro-ecological, social and economic characteristics. This is performed by simulating the behavior of individuals in an agent-based modeling framework which integrates the village characteristics as well as the family internal rules that condition access to economic and production activities. Villagers are differentiated according to the social and agro-ecological constraints they are subjected to. Two development project interventions are simulated, assuming no land scarcity: increasing the availability of inorganic fertilizers for farmers and an inventory credit technique based on millet grain. Two distinct approaches were used to model the rationale of farmers’ decision making: gains or losses in economic value or gains or losses in within-village “reputation”. Our results show that village populations do not respond en masse to development interventions. Reputation has little effect on the population behavior and should be considered more as a local proxy for wealth amongst villagers, suggesting the monetization of these societies. Populations involve themselves in the two simulated development interventions only at sites where savings are possible. Some level of household food security and investment capacity is actually required to take part in the development interventions, which are largely conditioned by family manpower and size. As long as uncultivated land remains available in the village territory, support for inorganic fertilizers has little impact in the absence of any intensification process. Inventory credit engages a maximum of 25% of the population at the site with medium agro-ecological conditions. Therefore, both interventions should be viewed as a potential support tool for a limited part of the population capable of going beyond the survival level, but not as a generic poverty-alleviation panacea.
Testing the impact of social forces on the evolution of Sahelian farming systems: a combined agent-based modeling and anthropological approach
(Journal Article, 2010-11) Saqalli, M.; Gerard, Bruno G.; Bielders, Charles L.; Defourny, Pierre
This article presents the results of a methodology based on an extensive sociological fieldwork in three different sites settled along a gradient of aridity in Nigerien Sahel. This fieldwork led to build a set of rules for the behaviour of individuals in non-pastoralist villages. We implemented these rules into an agent-based model simulating three village archetypes. Each archetype includes biophysical, economical, social agricultural and livestock modules. Results from simulations with no social transition processes show that villages specialize themselves into different economic activities according to natural resource specificities: A decreasing intensification gradient is observed from the most favoured site, with more local productions and good ecological indicators, to the less-favoured site, with a growing proportion of the population wealth coming from migration remittances and “off-shore” livestock. Two family transition processes were implemented, following field observations and literature-based hypotheses: family organizations evolve between a patriarchal mode and a non-cooperative mode following tensions due to income redistribution. Family inheritance systems evolve from a “customary” one-heir mode to a “local Muslim” mode in which all males inherits land. This evolution depends on family tensions due to land availability. Once introducing these processes, the population of each site differentiates itself into specialized groups according to size, assets and social status. Meanwhile, the group proportions and specializations strongly vary according to the sites but they are all characterized by the emergence of individualistic family types and the increase of the village populations’ robustness.
An agent-based approach to explore the effect of voluntary mechanisms on land use change: a case in rural Queensland, Australia
(Journal Article, 2010-12) Valbuena, Diego; Bregt, A.K.; McAlpine, C.; Verburg, P.H.; Seabrook, L.
In rural regions, land use changes (LUC) are often the result of the decision-making of individual farmers. To influence this decision-making, compulsory and voluntary mechanisms are implemented. However, farmers’ decision-making is a heterogeneous process that depends on their ability and willingness to take certain decisions. Discrepancies between farmers’ ability and willingness and the design of voluntary mechanisms occur frequently. This makes it necessary to understand how farmers’ participation in these mechanisms can affect LUC. The aim of this paper was to demonstrate an agent-based approach to analyse and explore how voluntary mechanisms can influence LUC processes in rural regions. This approach was applied to a rural region in Australia, where clearing of native vegetation has occurred for agricultural development. Historical land cover data and semi-structured interviews were used to parameterise an agent-based model. Factors that influence farmers’ ability and willingness to participate in these mechanisms were identified. Three scenarios were simulated with the model to explore how the implementation of different voluntary mechanisms can affect the landscape structure of the region. This paper identifies how the diversity of farmers’ decision-making can influence the landscape structure in the region. The advantages and limitations of an agent-based approach in relation to LUC research and policy are discussed.
Supplementation with groundnut haulms for sheep fattening in the West African Sahel
(Journal Article, 2007-04) Ayantunde, Augustine A.; Delfosse, P.; Fernández Rivera, S.; Gerard, Bruno G.; Dan-Gomma, A.
Groundnut haulms along with cowpea hay are major crop residues used for animal fattening in the West African Sahel. In traditional sheep fattening,feeds are always provided ad-hoc and in an unregulated fashion, which is rather wasteful. As a preliminary study to establish the optimal feeding levels of groundnut haulms for profitable sheep fattening, a feeding trial was conducted for 70 days with four levels of groundnut haulms (0, 150, 300 and 450 g/day) and a basal diet of bush hay. The effects of supplementation with groundnut haulms on feed intake, water consumption, live weight changes and economic return were determined. Twenty-four Peuhl Oudah rams with average initial weight of 28.6 kg (SD = 1.4) were randomly allocated to four treatments defined by the four levels of groundnut haulms in the diet. Faeces and urine were collected in weeks 5 and 9 of the trial. Digestible organic matter intake (g/(kg LW)0.75) and nitrogen intake (g/day) increased linearly with the level of groundnut haulms offered. Sheep that were fed only bush hay lost 18.4 g/day, while those that were offered 150, 300 and 450 g of groundnut haulms gained 1.4, 19.3 and 40.2 g/day, respectively. The gross return ranged from 1883 to 4946 FCFA per ram. Net benefit, after removing the feed and veterinary costs from the gross return, ranged from 368 to 1400 FCFA per ram.
Smart investments in sustainable food production: revisiting mixed crop-livestock systems
(Journal Article, 2010-02-12) Herrero, Mario; Thornton, Philip K.; Notenbaert, An Maria Omer; Wood, S.; Msangi, Siwa; Freeman, H.A.; Bossio, Deborah A.; Dixon, John A.; Peters, Michael; Steeg, Jeannette van de; Lynam, John K.; Rao, P.P.; MacMillan, Susan; Gerard, Bruno G.; McDermott, John J.; Seré Rabé, Carlos; Rosegrant, Mark W.
Farmers in mixed crop-livestock systems produce about half of the world’s food. In small holdings around the world, livestock are reared mostly on grass, browse, and nonfood biomass from maize, millet, rice, and sorghum crops and in their turn supply manure and traction for future crops. Animals act as insurance against hard times and supply farmers with a source of regular income from sales of milk, eggs, and other products. Thus, faced with population growth and climate change, small-holder farmers should be the first target for policies to intensify production by carefully managed inputs of fertilizer, water, and feed to minimize waste and environmental impact, supported by improved access to markets, new varieties, and technologies.
Maize as food and feed in intensive smallholder systems: management options for improved integration in mixed farming systems of east and southern Africa
(Journal Article, 2003-10) Romney, Dannie L.; Thorne, Peter J.; Lukuyu, Ben A.; Thornton, Philip K.
As systems intensify, crops and livestock become increasingly integrated. Forage from crops becomes a larger component of overall forage supply in small-scale systems. This paper integrates information from field trials, studying the effect of varying maize planting density, with modelling approaches to compare this with supplementation of maize stover, genetic improvement of stover digestibility and replacement of the maize crop with planted forage in east and southern Africa. Aggregate analyses for small-scale intensive (SSI) systems producing milk were carried out using a suite of models including CERES, CROPGRO, DRASTIC and ANORAC, scaling-up to regional level using GIS information. Increasing planting density increased the yield of thinnings, but decreased grain and stover yields. Model predictions of milk production from the thinnings and stover produced from one hectare of maize indicated that economic benefits to increased planting density could be achieved when the grain:milk price ratio was low, despite the negative effect on grain yield. Supplementation showed the greatest economic returns with small positive impacts on soil fertility and maize production. Replacing maize with planted forage inevitably increased milk at the expense of maize production. Again, for this intervention, grain:milk price ratios ranging from 0.19 to 2.88 across sub-Saharan Africa are likely to influence the decision of the farmer whether or not to trade milk for grain. Genetic enhancement of the digestibility of maize stover was found to have little impact on milk production because diets based on stover were deficient in nitrogen, preventing animals from benefiting from the increased energy supply resulting from digestibility increases. Other factors such as market access and stability, as well as individual objectives such as cash flow, food security and risk minimisation, were not explored in the present study but will influence household decisions. More complex analyses, accounting for these factors, may be required to predict adoption behaviour, however, the results of the study can be used to evaluate the potential returns to investment in research in the different areas using an economic surplus model.
Measuring the potential impacts of improved food-feed crops: methods for ex ante assessment
(Journal Article, 2003-10) Thornton, Philip K.; Kristjanson, Patricia M.; Thorne, Peter J.
The recent increased emphasis on impact assessment is due in part to the rapidly changing nature of funding for agricultural research and the shifts that have occurred in what is expected of the agricultural research community. The reasons for doing impact assessment are relatively clear: ex post studies can determine the impact of past investment in research on target beneficiaries and are a way to learn some of the lessons of the past. Ex ante studies can provide information to assist in the allocation of scarce research resources to activities that best match donors’ development objectives. In practice, impact assessment is often contentious and almost always difficult, particularly when livestock are involved. In this paper, we outline methods that can be used in ex ante impact assessment, and illustrate some of these in relation to three recent studies on improved food-feed crops in different places: improving the quality of millet and sorghum stover in India, using dual-purpose cowpea in West Africa, and alternatives for utilizing maize stover in the mixed systems of East and Southern Africa. Such impact assessments are neither cheap nor quick, and the methods that are most appropriate in any situation will depend not only on the resources and expertise available but most importantly on the exact nature of the questions being asked and the end-users of the results. Much remains to be done to maximize the utility of such assessments, particularly in the areas of quantitative model development, rapid qualitative method development, more effective integration of biophysical and socio-cultural indicators and approaches, and provision of baseline data against which to measure progress. Research resource allocation may well retain its somewhat haphazard nature in the future, but given the challenges facing agriculture in developing countries, a mechanism for attempting to ensure that research and extension really do contribute to widely held development goals has to be based on more than trial and error.
Approaches to improve the utilization of food-feed crops—synthesis
(Journal Article, 2003-10) Lenné, Jillian M.; Fernández Rivera, S.; Blümmel, Michael
This paper synthesizes the key findings presented in the previous 15 papers, and presents a summary of a discussion on best approaches, strategies and partnerships to improve the utilization of food–feed crops. The synthesis provides guidance for future research and development in crop–livestock systems in developing countries. It also stresses the need for greater integration, focus, coordination of efforts to improve the utilization of food–feed crops, if the benefits from advances in research and output delivery are to reach the hundreds of millions of resource-poor livestock keepers in developing countries.
Improving the production and utilization of sorghum and pearl millet as livestock feed: progress towards dual-purpose genotypes
(Journal Article, 2003-10) Blümmel, Michael; Zerbini, E.; Reddy, B.V.S.; Hash, C.T.; Bidinger, F.R.; Khan, A.A.
The overall objective of this work was to investigate variation in grain yield (GY), stover yield (SY), fodder quality of stover and their association in sorghum and pearl millet. These relationships were investigated in India in 12 genotypes of sorghum and six genotypes of pearl millet grown under high fertilizer (HF) and low fertilizer (LF) application. Fodder quality of stover was assessed by digestibility and intake measurements in bulls. In sorghum, highly significant genotype-dependent variation was found for GY, SY and fodder value of stover regardless of level of fertilizer application. GY and fodder quality of stover were not inversely related and the genotype with the highest GY, for example, had also the best fodder quality in the stover. High GY and high fodder quality in sorghum stover seem to be compatible traits. In pearl millet, genotypic variation in GY and SY and quality was expressed under HF but not under LF application. No consistent significant genotypic differences were found for fodder quality measurements in pearl millet except for cell wall digestibility. Digestible organic matter intake (DOMI) when bulls were fed to appetite was considered the crucial determinant of stover quality in sorghum and pearl millet. Live weight changes in bulls estimated by DOMI varied genotype-dependently from −140 to +100 g per day in 300 kg bulls. However, this paper argues that genotypes promoting high DOMI are only suitable for farmers with sufficient amounts of stover to allow the feeding of animals to appetite. Farmers with restricted amounts of stover are better served by genotypes that promote high digestibility under restricted feed intake.
Improving the production and utilization of cowpea as food and fodder
(Journal Article, 2003-10) Singh, B.B.; Ajeigbe, Hakeem A.; Tarawali, Shirley A.; Fernández Rivera, S.; Abubakar, M.
Cowpea (Vigna unguiculata (L.) Walp.) is an important food legume and an integral part of traditional cropping systems in the semi-arid regions of the tropics. The estimated worldwide area under cowpea is about 14 million ha of which West Africa alone accounts for about 9.3 million ha with annual production of about 2.9 Mt. Cowpea grains are consumed as food and the haulms are fed to livestock as a nutritious fodder. Farmers often grow a short-duration spreading variety for grain and a long-duration spreading variety for fodder, but the grain and fodder yields are poor due to low yield potential of the spreading varieties and also due to early cessation of rains. Therefore, IITA in collaboration with ILRI has initiated a systematic programme to develop medium-maturing, semi-erect, dual-purpose varieties with higher grain and fodder yields and with enhanced fodder quality. By crossing the late, traditional spreading varieties with improved early, semi-erect varieties, a semi-erect group of medium-maturing, dual-purpose varieties has been developed which yield over 1.5 t ha−1 grain and 2.5 t ha−1 haulms. Despite the high grain and fodder yields, the haulms of improved dual-purpose varieties have similar crude protein content (17–18%) and dry matter digestibility (64–71%) compared to the local varieties. Controlled sheep feeding experiments have shown an average live weight gain of about 80 g per animal per day with 200–400 g per day of cowpea haulms as a supplement to a basal diet of sorghum stover. This was 100% higher than the average live weight gain of animals fed sorghum fodder alone. These results indicate that improved dual-purpose varieties can play an important role in enhancing crop–livestock integration in West Africa.
Crop management factors influencing yield and quality of crop residues
(Journal Article, 2003-10) Reddy, B.V.S.; Sanjana Reddy, P.; Bidinger, F.R.; Blümmel, Michael
In the semi-arid tropics, over two-third’s of the world’s people depend on agriculture within which livestock play a major role in building rural livelihoods. Crop residues (fodder/stover) are important feed resources for ruminants. This review was undertaken with the objective of improving understanding of the role of various crop management factors in affecting the productivity and quality of crop residues. Variability in productivity and quality of residues can be of both genetic and non-genetic origin. Recommended agronomic practices vary according to crop and cultivar and can release the maximum genetic potential determining quantity and quality of residues. Planting method and planting rate recommendations should be followed to maximise productivity. Although low density planting improved fodder quality, fodder yield declined. Time of sowing affected fodder yield in most of the crops, but fodder quality was not generally affected. It was common to observe that application of nitrogen (up to 120 kg ha−1) in cereals and application of phosphorus (up to 60 kg ha−1) in legumes improved the green and dry fodder yields, as well as crude protein (CP), crude fibre (CF) and other quality parameters. Inoculation of cereal seed with nitrogen fixing bacteria such as Azotobacter and seed of pulses with phosphate solubilising bacteria has been reported to decrease fertiliser needs and improve the CP and in vitro dry matter digestibility (IVDMD) of fodder. Irrigating at more frequent intervals by splitting the same quantity of irrigation water into smaller irrigations and at critical stages improved dry matter and CP yields. Hand weeding resulted in better weed control efficiency and stover yield than application of herbicides. However, application of herbicides resulted in the greatest benefit:cost ratio. Manual harvesting resulted in lower losses than mechanical harvesting, and may affect quality depending on the extent of loss of different fodder components. Drought stress yielded more digestible organic matter due to increases in the proportion of leaves compared to stems. Saline conditions affected seed germination and crop yields. Several methods are suggested to counteract the effects of salinity. Intercropping of cereals with legumes improved fodder nutritional quality (mostly protein content). In almost all crops, a positive association was found between fodder and grain yield indicating simultaneous improvement in both characters. In most cases, fodder yield and digestibility were positively correlated and showed positive association with plant height, leaf number and the number of tillers per plant, but there were limits and variation among crops. The ICRISAT–ILRI partnership experiments were conducted with a diverse set of sorghum and pearl millet cultivars at ICRISAT, India. Planting density levels in both crops did not influence forage quality although some fodder yield traits were affected. A significant interaction of genotype with planting density was observed for grain and fodder yield in sorghum and grain yield and harvest index in pearl millet. Adherence to recommended crop management practices can potentially facilitate the release of the maximum genetic potential determining quality and yield parameters for improved animal production.

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