Smallholder Farmers In Africa Research Articles

Genetic architecture of kernel composition in global sorghum germplasm

BackgroundSorghum [Sorghum bicolor (L.) Moench] is an important cereal crop for dryland areas in the United States and for small-holder farmers in Africa. Natural variation of sorghum grain composition (protein, fat, and starch) between accessions can be used for crop improvement, but the genetic controls are still unresolved. The goals of this study were to quantify natural variation of sorghum grain composition and to identify single-nucleotide polymorphisms (SNPs) associated with variation in grain composition concentrations.ResultsIn this study, we quantified protein, fat, and starch in a global sorghum diversity panel using near-infrared spectroscopy (NIRS). Protein content ranged from 8.1 to 18.8%, fat content ranged from 1.0 to 4.3%, and starch content ranged from 61.7 to 71.1%. Durra and bicolor-durra sorghum from Ethiopia and India had the highest protein and fat and the lowest starch content, while kafir sorghum from USA, India, and South Africa had the lowest protein and the highest starch content. Genome-wide association studies (GWAS) identified quantitative trait loci (QTL) for sorghum protein, fat, and starch. Previously published RNAseq data was used to identify candidate genes within a GWAS QTL region. A putative alpha-amylase 3 gene, which has previously been shown to be associated with grain composition traits, was identified as a strong candidate for protein and fat variation.ConclusionsWe identified promising sources of genetic material for manipulation of grain composition traits, and several loci and candidate genes that may control sorghum grain composition. This survey of grain composition in sorghum germplasm and identification of protein, fat, and starch QTL contributes to our understanding of the genetic basis of natural variation in sorghum grain nutritional traits.

Agricultural biotechnology policy review in Africa: A case study of Kenya

Production of genetically modified crops and animals is still a widely debated topic across the globe. There are a lot of players when it comes to the acceptance and adoption of biotechnology in agriculture for the aim of increased food production, quality addition among other goals. One of the key stake holders are policy makers. Many African countries have developed Agricultural policies which address the research, development, production and regulation of genetically engineered crops and animals. Through these policies, A number of new crops have been developed tested and approved, addressing important traits of particular significance for smallholder farmers in Africa. Since most of these policies are still new, there are issues that face the agricultural biotechnology sector in these countries that making it difficult to achieve the potential. The major problems include misinformation and politicization of core issues relating to biotechnology. However, these issues can be addressed easily with implementation of the guidelines delayed in the policy. Kenya developed and adopted such a comprehensive policy in 2006. However, to date, the full implementation and complete adherence to the document guidelines has not been fully achieved. This paper uses several case studies to review the Agricultural Biotechnology policy in Kenya, evaluating what is outlined in the policy adopted slightly more than a decade ago against what has been achieved so far.

COWPEA (VIGNA UNGUICULATA) CROPS IN AFRICA CAN RESPOND TO INOCULATION WITH RHIZOBIUM

SUMMARYCowpea (Vigna unguiculata L. Walp) is the most important food grain legume in Africa. Cowpea is nodulated by rhizobium bacteria in almost all soils of the tropics, but studies performed in the 1970s and 1980s in Nigeria suggested only modest responses of grain yield in the field to inoculation of selected rhizobium strains. More recently, experiments performed in Brazil have shown that cowpea responded to inoculation of rhizobium selected locally and grain yields increased by up to 30%. We tested some of the Brazilian strains on cowpea at a site in northern Mozambique and at several sites in Northern Ghana. At all sites phosphorus fertilizer (26 kg P ha−1) was added to all plots. At the site in Mozambique despite considerable damage to the crop by the parasitic yellow witchweed (Alectra vogelii), grain yields were more than doubled by inoculation of one of the Brazilian strains and reached 1.4 Mg ha−1. In on-station experiments conducted in 2012 in June and August in northern Ghana using the local cowpea variety Padi-Tuya as the test crop, nodule weight at 35 days after planting (dap) tripled with rhizobium strain BR 3299 (530 mg plant−1) in August with the other inoculants (BR 3267 and a mixture of BR 3267 and BR 3299) also increased nodule weight to over 300 mg plant−1. In the first on-station experiment, grain yields were doubled by the inoculation of any of the three rhizobium strains, and in the second experiment, significant increases in grain yield ranged from 39% to 57% and reached over 2.0 Mg ha−1. Similar increases in nodulation and grain yield due to inoculation were observed in 22 on-farm trials. Nitrogen fertilizer application promoted vegetative growth but did not increase grain yield and nodulation. Inoculating cowpea with highly effective rhizobium strains can therefore enhance grain yield of smallholder farmers in Africa.

Making the Most of What We Already Know: A Three-Stage Approach to Systematic Reviewing.

Conducting a systematic review in social policy is a resource-intensive process in terms of time and funds. It is thus important to understand the scope of the evidence base of a topic area prior to conducting a synthesis of primary research in order to maximize these resources. One approach to conserving resources is to map out the available evidence prior to undertaking a traditional synthesis. A few examples of this approach exist in the form of gap maps, overviews of reviews, and systematic maps supported by social policy and systematic review agencies alike. Despite this growing call for alternative approaches to systematic reviews, it is still common for systematic review teams to embark on a traditional in-depth review only. This article describes a three-stage approach to systematic reviewing that was applied to a systematic review focusing in interventions for smallholder farmers in Africa. We argue that this approach proved useful in helping us to understand the evidence base. By applying preliminary steps as part of a three-stage approach, we were able to maximize the resources needed to conduct a traditional systematic review on a more focused research question. This enabled us to identify and fill real knowledge gaps, build on work that had already been done, and avoid wasting resources on areas of work that would have no useful outcome. It also facilitated meaningful engagement between the review team and our key policy stakeholders.

Tradeoffs and complementarities in the adoption of improved seeds, fertilizer, and natural resource management technologies in Kenya

AbstractThere is widespread consensus that agricultural technology has an important role to play for poverty reduction and sustainable development. There is no consensus, however, about the types of technologies that are best suited for smallholder farmers in Africa. While some consider natural resource management (NRM) technologies as most appropriate, others propagate input intensification with a stronger role of the private sector. In the public debate, these two strategies are often perceived as incompatible. Environmental non‐governmental organizations in particular consider low‐external input strategies as the only sustainable form of agriculture, a view that has considerable influence on policymakers and the international donor community. Most existing research studies on smallholder innovation focus on the adoption of individual technologies, so that comparisons between different types of technologies in the same context are not easily possible. We use representative data from maize‐producing households in Kenya and a multivariate probit model to analyze the adoption of different types of technologies simultaneously. Results indicate that NRM technologies and strategies that build on external inputs are not incompatible. Interesting complementarities exist, which are not yet sufficiently exploited because many organizations promote either one type of technology or the other, but rarely a combination of both.

Linkage disequilibrium in the estimation of genetic and demographic parameters of extensively raised chicken populations

Smallholder farmers in Africa and other developing countries raise village chickens under low input production systems characterised by minimal management and veterinary interventions. However, village chickens have a major contribution to village communities as a source of protein, income and cultural needs. The village chickens are described as nondescript birds that have not been developed as a breed and with uncharacterised genetic attributes. Local chickens are found in the most marginalised farming systems, to which they have adapted and survived the harsh production and environmental conditions. Such survival and adaptive attributes need to be characterised, conserved, and utilised. Several studies on Southern African local chickens have revealed high genetic variation within and among the village chicken populations and indicated that village chickens contribute diversity that is unique and different from that of commercial and specialised chicken populations. The availability of whole genome single nucleotide polymorphism (SNP) data facilitates the use of powerful statistical methods for in depth investigations into the evolutionary history and population demographics of village chickens. Linkage disequilibrium (LD), as a function of effective population size, has been used to estimate rate and level of inbreeding as well as selection pressures in the absence of pedigree information. The extent and distribution of LD in the genome has been exploited to shed light on the origin and domestication of animals and facilitate an understanding of breeds' relatedness. The Illumina iSelect chicken 60K SNP chip has over 54 000 SNPs that have found application in population and quantitative genetics studies and has revealed demographic history, effective population size and level of genetic erosion in commercial and traditional/village chicken populations. The recent launching of the 600 K Affymetrix® Axiom® HD genotyping array for chickens and the ever decreasing cost of sequencing will see improved estimation of LD and the associated population parameters.

Does the New Alliance for Food Security and Nutrition impose biotechnology on smallholder farmers in Africa?

Almost one in three people who live in sub-Saharan Africa (SSA) are hungry, higher than anywhere else. This magnitude of food insecurity coupled with slow progress in regional integration, disease and epidemics, poor access to markets, gender disparities, lack of land tenure rights, and governance and institutional shortcomings on the continent have been used to justify a narrative for the inclusion of biotechnology in smallholder agriculture in SSA. The fact, however, suggests that even in the face of these challenges, smallholder farmers in SSA still produce 70% of the food on the continent. We critically examine the introduction of biotechnology in smallholder farming within the context of the New Alliance for Food Security and Nutrition and public–private partnerships in SSA. We explicitly address the bioethical concerns and implications for technology adoption goals in line with a neoliberal economic model that is encouraging smallholder farmers to adopt biotechnology as a way to secure more food for communities. This paper is not meant to pose a simplistic pro or anti stance on genetically modified (GM) crops or biotechnology, but rather to situate the debate about GM technology within issues of power, control in the global food agriculture systems, and point to the bioethical concerns that affect the lives of smallholder farmers and their families on a daily basis.

The Effects of Training, Innovation and New Technology on African Smallholder Farmers' Economic Outcomes and Food Security: A Systematic Review

The Effects of Training, Innovation and New Technology on African Smallholder Farmers' Economic Outcomes and Food Security: A Systematic Review

Haemonchotolerance in West African Dwarf goats: contribution to sustainable, anthelmintics-free helminth control in traditionally managed Nigerian dwarf goats.

West African Dwarf (WAD) goats are extremely important in the rural village economy of West Africa, but still little is known about their biology, ecology and capacity to cope with gastrointestinal nematode (GIN) infections. Here, we summarise the history of this breed and explain its economic importance in rural West Africa. We review recent work showing that Nigerian WAD goats are highly trypanotolerant and resist infections with Haemonchus contortus more effectively than other breeds of domestic goat (haemonchotolerance). We believe that haemonchotolerance is largely responsible for the generally low level GIN infections and absence of clinical haemonchosis in WADs under field conditions, and has contributed to the relatively successful and sustainable, anthelmintics-free, small-scale system of goat husbandry in Nigeria’s humid zone, and is immunologically based and genetically controlled. If haemonchotolerance can be shown to be genetically controlled, it should be possible to exploit the underlying genes to improve GIN resistance among productive fibre and milk producing breeds of goats, most of which are highly susceptible to nematode infections. Genetic resistance to GIN and trypanosome infections would obviate the need for expensive chemotherapy, mostly unaffordable to small-holder farmers in Africa, and a significant cost of goat husbandry in more developed countries. Either introgression of resistance alleles into susceptible breeds by conventional breeding, or transgenesis could be used to develop novel parasite-resistant, but highly productive breeds, or to improve the resistance of existing breeds, benefitting the local West African rural economy as well as global caprine livestock agriculture.

Conceptualizing Microfinance For Effective Smallholder Farming In Africa

Smallholder farmers in Africa desperately need pro-poor interventions to alleviate their poverty through self-sustenance. In Africa, poverty is more prevalent in rural areas, where the overwhelming majority (about 80%) of Africas population lives and about 72% are poor. Microfinance cannot have substantial impact on poverty until it significantly penetrates the rural areas where small-scale agricultural activities by smallholder farmers need financial support. This paper thus attempts to conceptualise microfinance for smallholder farming in Africa which is done from the integrated view as opposed to a minimalist view.The integrated view was selected because it focuses on the provision of credit facilities plus related follow-up services such as training, whilst the minimalist view is concerned about giving credit only. The paper relied on literature review and digestion to conceptualise microfinance as a strategy for boosting smallholder agricultural production. Many rural farmers have no access to the traditional financial system. Therefore, basic financial services are essential for the management of their productive endeavors. This paper argues that microfinance plays a pivotal role in the commercialisation, not only of smallholder farming activities but also the successful implementation of agricultural ideas. Microfinance is one way of helping farmers to sharpen their agricultural ideas so as to promote rural economic development.With this background it has become imperative to explore the commercialisation of rural agriculture so as to empower the farmers. The financial sector in most countries does not cater for rural finance because they require physical collateral security that rural people do not have. In this article, micro-finance is seen to be a useful intervention that can be employed to economically empower the agricultural sector.

Issues and concerns in smallholder livestock genetic improvement programs in Africa.

Improvement of smallholder livestock genetic resources is of vital importance to agriculture, food production, rural development and the environment on the African continent. Inconclusive considerable debate on smallholder livestock improvement strategies and utilization of local livestock genetic resources has been going on since the past two decades. This has been necessitated by the realization of the need to reduce poverty and enhance food security and produce more animal products to feed the ever increasing national populations in Africa, which seen more compelling than ever. It has been acknowledged that partly the overall continental increase in livestock productivity can be achieved through appropriate and support of the smallholder livestock improvement programs. It is believed that within the smallholder livestock production systems which is characterized by a generally low input-output system, the sustainability of animal breeding efforts to improve animal productivity becomes a dominant factor. Smallholder livestock improvement is not achieving the expected increase in livestock productivity to meet the growing demand for animal products for several reasons, including poor infrastructure, investment environment, financial resources and lack of local expertise and scientific research in addition to poor livestock support services. There is perceived need for improved livestock production in the smallholder areas, however livestock productivity has remained very low, but indigenous livestock are numerous which makes them attractive as potential tool for poverty reduction and improvement of family food security and livelihoods in smallholder farming in Africa. Changes in the demand for livestock products will be largely be driven by human population growth, income growth and urbanization, however the production response in different livestock production systems to meet this demand will be associated with livestock improvement thrust which take into account the modern science and technology in livestock improvement. This discussion attempts a rapid summary of some issues and concerns perceived important in promoting smallholder livestock improvement programs, in relation to recent and previous outcomes, coupled with a brief assessment of some of the challenges faced in implementation of smallholder livestock improvement programs. Some of the challenges and opportunities such as unfavorable livestock policies, dilapidated infrastructure and limited livestock research and characterization of local livestock populations are highlighted. Genetic improvement of livestock indigenous to Africa for targeted performance characteristics of economic benefit for smallholder farmers is necessary for effective selection for both use in straight breeding and crossbreeding. In future, livestock improvement programs are likely to be increasingly characterized by differences between developed and developing countries, and between highly intensive production systems on the one hand and smallholder livestock production on the other hand. How smallholder livestock improvement programs will be implemented in the coming decades is highly uncertain, however, of the many uncertainties, one seem over-arching. Can future demand for livestock products be met through sustainable intensification of smallholder livestock improvement programs on the African continent? With the right institutional and financial arrangements, government, research institutions and donor agencies support can assist in successful implementation of smallholder livestock improvement programs on the continent, improving the capacity of smallholder livestock resource poor farmers to contribute significantly to individual national economies.

SEQUENCING INTEGRATED SOIL FERTILITY MANAGEMENT OPTIONS FOR SUSTAINABLE CROP INTENSIFICATION BY DIFFERENT CATEGORIES OF SMALLHOLDER FARMERS IN ZIMBABWE

SUMMARYResearch has proved that integrated soil fertility management (ISFM) can increase crop yields at the field and farm scales. However, its uptake by smallholder farmers in Africa is often constrained by lack of technical guidelines on effective starting points and how the different ISFM options can be combined to increase crop productivity on a sustainable basis. A 4-year study was conducted on sandy soils (<10% clay) on smallholder farms in eastern Zimbabwe to assess how sequencing of different ISFM options may lead to incremental gains in soil productivity, enhanced efficiency of resource use, and increase crop yields at field scale. The sequences were primarily based on low-quality organic resources, nitrogen-fixing green manure and grain legumes, and mineral fertilizers. To enable comparison of legume and maize grain yields among treatments, yields were converted to energy (kilocalories) and protein (kg) equivalents. In the first year, ‘Manure-start’, a cattle manure-based sequence, yielded 3.4 t ha−1of maize grain compared with 2.5 and 0.4 t ha−1under a woodland litter-based sequence (‘Litter-start’) and continuous unfertilized maize control, respectively. The ‘Manure-start’ produced 12 × 106kilocalories (kcal); significantly (p< 0.05) out-yielding ‘Litter start’ and a fertilizer-based sequence (‘Fertilizer-start’) by 50%. A soyabean-based sequence, ‘Soya-start’, gave the highest protein production of 720 kg against <450 kg for the other sequencing treatments. In the second year, the sequences yielded an average of 5.7 t ha−1of maize grain, producing over 19 × 106kcal and 400 kg of protein. Consequently, the sequences significantly out-performed farmers’ designated poor fields by ~ fivefold. In the third year, ‘Soya-start’ gave the highest maize grain yield of 3.7 t ha−1; translating to 1.5 and 3 times more calories than under farmers’ designated rich and poor fields, respectively. In the fourth year, ‘Fertilizer-start’ produced the highest calories and protein of 14 × 106kcal and 340 kg, respectively. Cumulatively over 4 years, ‘Manure-start’ and ‘Soya-start’ gave the highest calories and protein, out-performing farmers’ designated rich and poor fields. Sunnhemp (Crotalaria junceaL.)-based sequences, ‘Green-start’ and ‘Fertilizer-start’, recorded the highest gains in plant available soil P of ~ 4 mg kg−1over the 4-year period. Assessment of P agronomic efficiencies showed significantly more benefits under the ISFM-based sequences than under farmers’ designated rich and poor fields. Based on costs of seed, nutrients and labour, ‘Soya-start’ gave the best net present value over the 4 years, while ‘Fertilizer-start’ was financially the least attractive. Overall, the ISFM-based sequences were more profitable than fields designated as rich and poor by farmers. We concluded that ISFM-based sequences can provide options for farm-level intensification by different categories of smallholder farmers in Southern Africa.

GAME CHANGERS FOR IRRIGATED AGRICULTURE—DO THE RIGHT INCENTIVES EXIST?

ABSTRACTGame changers to achieve sustainable intensification of agriculture are possible in the irrigation sector and they focus mainly on getting more with less. There is, however, still a long way to go to replicate, adapt and develop approaches to take such ideas to scale and increase productivity within existing agricultural water management contexts. Recognizing this, the CGIAR Research Program on Water, Land and Ecosystems (WLE) seeks to achieve sustainable intensification through productive and efficient use of resources, restoring the productive capacity of degraded agricultural landscapes and reducing risk and uncertainty through the sustainable management of land and water resources. WLE research has contributed to reductions in fertilizer use through substitution with reused organic waste products, improved groundwater governance in India and changing the policy framework for smallholder farmers in Africa to improve their access to simple water management technologies. Achieving more widespread adoption of these kinds of practices requires evidence which can increase our understanding of the constraints and effectiveness of different options; an openness to explore new and sometimes counter‐intuitive ideas; working across institutional boundaries; consideration of the rainfed to irrigation continuum; and a commitment to provide the necessary policy framework, capacity and resources to support incentives for change. Copyright © 2014 John Wiley & Sons, Ltd.

The role of tree domestication in green market product value chain development

Internationally, there is interest in increasing the trade in ‘green’ market products, such as organic, fair trade, reduction of deforestation and forest degradation/reduction of deforestation and forest degradation+ for reduced deforestation and mitigation of climate change, and environmental goods and services. This crucially needs to be extended to the many poor, hungry and marginalized smallholder farmers in developing countries. In this context, agroforestry tree domestication has made great progress over the last 20 years, especially in Africa with the emergence of many new tree crops for food, cosmetic and pharmaceutical industries across many agro-ecological zones. Tree domestication is important for the enhancement of economic returns as value chains from local to global become more sophisticated and demand higher quality, greater uniformity and a regular and continuous supply. Local farmers are now developing cultivars creating direct benefits from the marketing of food and non-food products in local and regional markets. This creates business and employment opportunities in local cottage industries. Likewise, through the indirect environmental and ecological services provided by trees, food security can be greatly enhanced by closing the yield gap (the difference between the potential and actual yield) of modern crop varieties. In this way, agroforestry is adding income generation to agroecological approaches which together reverse the cycle of land degradation and social deprivation and transforming the lives of poor farmers. However, these benefits do not come without some risks from the loss of genetic diversity, local rights over genetic resources and exploitation by unscrupulous entrepreneurs. Agroforestry developments are therefore focusing on better access to ‘green’ business opportunities for poor smallholder farmers in Africa by maximizing the benefits and minimizing the risks.

The size and nature of the evidence-base for smallholder farming in Africa: a systematic map

Relevant systematic reviews and impact evaluations were systematically sought and described in order to assess the size and nature of the evidence-base about the effectiveness of interventions for smallholder farmers in Africa. A total of 21 relevant systematic reviews and 415 reports of impact evaluations were identified. This paper describes this African evidence-base in terms of the interventions and outcomes assessed, and the geographical spread of the primary research across the continent. Gaps in the evidence-base are identified and recommendations made for future research.

Climate Change Adaptation and Vulnerability: A Case of Rain Dependent Small-Holder Farmers in Selected Districts in Zambia

Food crop production by small-holder farmers in Africa is particularly vulnerable to climate change, given high dependence on rainfall coupled with limited adaptive capacity. In Zambia, smallholder farmers contribute about 79% of national stable food requirements particularly maize. This paper attempted to establish levels of food security in each of the three agro-ecological zones of Zambia, and evaluated the current adaptive measures of rain dependent small-holder farmers against climate change risks. The challenges farmers are facing in adapting to the change risks were identified and livelihood vulnerability assessed. The findings indicate that rain dependent small-holder farmers in Zambia are highly vulnerable to weather related shocks which impact greatly on their food production; and that the levels of vulnerability vary across gender and per agro-ecological zone. After the evaluation of scenarios including staple food crop yields (maize), the authors conclude that most rain-fed small-holder farmers in Zambia (about 70%) are facing considerable hardships in adapting to the changing climate, which in turn, undermines their contribution to food security. While efforts by government have been made to assist farmers towards climate change adaptation, there still remains many challenges to achieve the desired outcomes. Most farmers (66%) are unable to afford certain alternatives, such as those of agro-forestry or conservation. Difficulties in accessing markets, poor road infrastructure, fluctuating market prices, high costs and late deliveries of farming in-puts were found to be among the major challenges that farmers are facing in Zambia. There are also no systematic early warning systems in place against natural hazards and disasters. This makes farming a difficult undertaking in Zambia.

Agricultural Value Chains and Smallholder Producer Relations in the Context of Supermarket Chain Proliferation in Southern Africa

Access to regional markets by small scale producers remains a problem in Southern Africa, yet retailing is becoming big business. A proliferation of supermarkets has been witnessed since the 1990s with South Africa’s Shoprite supermarket becoming a major player in African markets. Supermarkets play a critical role of food systems development in Southern Africa but theissues of concern pertain to how increased aggregate value can be generated for agricultural produce whilst at the same time retaining more value nationally/locally for smallholder agricultural producers. This paper focuses on small producers, characterising food systems evolution in Southern Africa and highlighting how small producers are relating with supermarkets. Drawing on existing empirical work to examine successful agribusiness initiatives for smallholder farmers in Africa in accessing regional value chains, the paper argues that ineffective regional policies contribute to forces preventing upgrading of smallholder farmers into regional markets. An analysis that synthesises various emerging issues regarding the relations between supermarkets and small producers is presented to inform research themes for uptake into policy formulation.

Commercialisation: A meta-approach for agricultural development among smallholder farmers in Africa?

This paper presents a critique of commercialising smallholder farming for agriculture in Sub-Saharan Africa. First it questions the validity of an overarching ‘metanarrative’ approach to development. Then it discusses the different types of knowledge, values and method and draws attention to the increasingly heterogeneous development policy context and also the heterogeneity among the smallholder ‘targets’ of agrifood policies.Second, a case study exemplifies this critique in the context of an existing multistakeholder strategy of commercialising the Zambian cassava sector. Although limited in scope, the primary research illustrates how a commercial supply response should not be assumed from within a rural sector more concerned with food security.The study casts doubt on the validity of a commercialising metanarrative. Rather, it endorses the need for a multidisciplinary understanding of the particular and local context which influences knowledge generation and development design, accounting for different value systems and perceptions of reality and smallholder farmer decision making within heterogeneous contexts.

Pushing the envelope? Maize production intensification and the role of cattle manure in recovery of degraded soils in smallholder farming areas of Zimbabwe

Soil fertility decline is a major constraint to crop productivity on smallholder farms in Africa. The objective of this study was to evaluate the long-term (up to nine years) impacts of nutrient management strategies and their local feasibility on crop productivity, soil fertility status and rainfall infiltration on two contrasting soil types and different prior management regimes in Murehwa, Zimbabwe. The nutrient management strategies employed in the study were: a control with no fertiliser, amendments of 100kg Nha−1, 100kg N+lime, three rates of manure application (5, 15 and 25tha−1) in combination with 100kg Nha−1, and three rates of P fertiliser (10, 30 and 50kg Pha−1) in combination with 100kg N, 20kg Ca, 5kg Zn and 10kg Mnha−1. Maize grain yields in sandy soils did not respond to the sole application of 100kg Nha−1; manure application had immediate and incremental benefits on crop yields on the sandy soils. A combination of 25tha−1 manure and 100kg N gave the largest treatment yield of 9.3tha−1 on the homefield clay soils, 6.1tha−1 in the clay outfield, 7.6tha−1 in the homefield and 3.4tha−1 in the eighth season. Yields of the largest manure application on the sandy outfields were comparable to yields with 100kg N in combination with 30kg P, 20kg Ca, 5kg Zn and 10kg Mnha−1 in the homefields suggesting the need to target nutrients differently to different fields. Manure application improved rainfall infiltration in the clay soils from 21 to 31mmh−1 but on the sandy soils the manure effect on infiltration was not significant. Despite the large manure applications, crop productivity and SOC build-up in the outfield sandy soils was small highlighting the difficulty to recover the fertility of degraded soils. The major cause of poor crop productivity on the degraded sandy soils despite the large additions of manure could not be ascertained. The current practice of allocating manure and fertiliser to fields closest to homesteads exacerbates land degradation in the sandy outfields and increases soil fertility gradients but results in the most harvest for the farm. On clay soils, manure may be targeted to outfields and mineral fertiliser to homefields to increase total crop productivity. Farmers who owned cattle in the study site can achieve high manure application rates on small plots, and manure application can be rotated according to crop sequences. Consistent application of manure in combination with mineral fertilisers can be an effective option to improve crop yield, SOC and moisture conservation under smallholder farming conditions. Combined manure and mineral fertiliser application can be adapted locally as a feasible entry point for ecological intensification in mixed crop–livestock systems.

Evidence on Key Policies for African Agricultural Growth

It is widely agreed that reducing poverty in Africa south of the Sahara (SSA) depends largely on stimulating growth in agriculture. To this end, heads of state in Africa rallied to form the pan-African Comprehensive African Agriculture Development Programme (CAADP) with the goal of raising investments and improving strategy implementation. However, while implementing an agricultural agenda under the CAADP framework, more and more countries have realized that increasing public investment in agriculture alone is not enough. Policy can play an important role not only to make public investment more efficient, but also is crucial for incentivizing private sector and farmer investment in agriculture. Against this backdrop this paper takes stock of current agricultural policies in SSA with a view to identifying policies that are working as well as areas for improvement. The paper examines policies to encourage the adoption of agricultural inputs, initiate greater private-sector investment in agriculture and agro-industries, and manage price volatility while encouraging openness. The paper further reviews successful land tenure policies and property rights systems, reviews the evidence on the synergies between agriculture and nutrition, and examines how CAADP is laying the institutional architecture for improved policy formulation in Africa. In general, the paper finds that although substantial progress has been made, there is considerable scope for improvement. This is not surprising given the relatively primitive and deeply rooted nature of smallholder farming in Africa. Evidence synthesized in the paper supports the view that most policies cannot be implemented in isolation. Rather, policies tend to be most effective when implemented along with complementary policies and public investments.