Soil and cropping system research in semi-arid West Africa as related to the potential for conservation agriculture

Semi-arid West Africa faces challenges to increase sorghum and pearl millet production to meet food needs for a growing human population while increasing soil carbon (C), nutrient levels, and water holding capacity that are documented benefits of conservation agriculture. This review focuses on the wealth of research on cropping systems, tillage, crop residue, nutrient, and weed management as related to conservation agriculture. It also identifies needs for multidisciplinary, integrative research to assist the transition from current production systems to conservation agriculture. Crop residue use as livestock feed, or fuel are major constraints to adoption of conservation agriculture, which could be reduced by wood production in agroforestry systems, alternate energy sources, and increased forage supply. Crop residue and grain yields are related, thus improved crop, soil, water, nutrient, and weed management to increase grain yield would also increase the supply of crop residue with potential for ‘left over’ crop residue being available for soil mulching. Incorporating indigenous shrubs and/or cover crops could also increase crop residue supply. Species diversity can be increased through crop rotation, agroforestry, cover crops, and intercrops. Higher grain and stover yields and increased profit potential for resource-poor farmers in West Africa will be required before wide-scale adoption of conservation agriculture will be possible.     

Conservation practice complementarity and timing of on-farm adoption

The adoption of conservation practices is a dynamic process. Factors that vary over time can affect farmers’ decision to adopt and adoption timing. We used a duration model to evaluate the farmer's adoption time for continuous no-till (CNT), cover crops (CCs), and the variable-rate application of inputs (VRA). We found that producers who had previously adopted soil conservation practices were more likely to adopt additional complementary practices. Farmers using crop rotation adopted CNT and CCs approximately 48% and 62% faster than farmers without a crop rotation, respectively. The CC adoption time was also reduced by 70% for farmers who had adopted CNT. Complementarities between conservation practices may enhance the benefits from adoption and allow farmers to adopt bundles of conservation practices more quickly over time. This can be taken advantage of in conservation programs by promoting or requiring practices first that enhance adoption of other practices. We also found important heterogeneity in the adoption speed associated with farm management characteristics, producers’ attitudes, weather patterns, and crop prices.     

Adoption of conservation agriculture in Europe: Lessons of the KASSA project

According to KASSA findings, conservation agriculture is less adopted in Europe compared to other adopting regions and, reduced tillage is more common than no-tillage and cover crops. Currently, it is not popularised and it is less researched. The lack of knowledge on conservation agriculture systems and their management and, the absence of dynamic and effective innovation systems make it difficult and socio-economically risky for European farmers to give up ploughing which is a paradigm rooted in their cultural backgrounds. In Norway and Germany the adoption of conservation agriculture has been encouraged and subsidised in order to mitigate soil erosion. In the other European countries the adoption process seems mainly driven by farmers and, the major driving force has been the cost reduction in machinery, fuel and labour saving. Soil and water conservation concerns did not appear as main drivers in the European farmers’ decision to shift or not to conservation agriculture.The shift of European farmers to conservation agriculture is being achieved through a step-by-step attitude, large scale farms are the most adopters. This adoption trend may grow in the future. Indeed, the need to improve farms’ competitiveness, the market globalization and the steady increase of fuel cost will likely contribute to arouse European farmers’ interest in conservation agriculture as it slashes significantly the production costs.Conservation agriculture is not equally suitable for all the European agroecosystems. The need of soil and water conservation in Europe requires anticipating the ongoing process in order to improve its ecological and socio-economic sustainability. Priority would be to define which regions in Europe are the most suitable for conservation agriculture taking into account climate and soil constraints, length of growing period, water availability and quality, erosion hazards and farming conditions. Policy favouring the use of soil cover and profitable crop rotations as management strategies for weed, pest and diseases control will certainly allow developing and disseminating efficient and acceptable conservation agriculture systems.     

Does Conservation Agriculture Change Labour Requirements? Evidence of Sustainable Intensification in Sub-Saharan Africa

Population growth, increasing wealth and changing diets require agriculture in Sub-Saharan Africa to intensify to meet future food demand and ensure food security in the region. Conservation agriculture can increase yields in the long run and reduce the negative environmental impacts of intensive farming. In changing the mix of resources used and how they are managed, the adoption of conservation agriculture can have a direct impact on farm labour. We study the relationship between conservation agriculture and labour input requirements as observed in five Sub-Saharan African countries. We focus on the amount of work required and the source of the work employed (household or hired, by gender, by children and by production stage). We apply multinomial endogenous switching regression models on a panel of household and farm data from Ethiopia, Kenya, Malawi, Mozambique and Tanzania. We find that conservation agriculture increases farms’ labour input requirements. Higher demand is driven by more work during the harvesting and threshing stages. Increases in labour requirements are usually met by household labour, not paid work. The workload change is also higher for women than for men, and, in certain cases, is met by children.     

Economic Liberalization and Smallholder Productivity in Tanzania. From Promised Success to Real Failure, 1985–1998

In the mid-1980s, Tanzania adopted a programme for economic liberalization of the entire economy, including agriculture. After pressure from the IMF and the World Bank in particular, but also from most of the bilateral donors, agricultural producer and input prices were decontrolled, panterritorial prices were abolished, subsidies were removed and trade in agricultural products and inputs was to a large extent taken over by private traders. The international donor community promised that economic liberalization would provide a strong stimulus to Tanzanian agriculture, resulting in increasing yields, increased labour productivity, rising agricultural production and higher incomes. However, available data show that, as far as food crop production is concerned, this promise has not been fulfilled. Even compared to the 'crisis years' 1979–1984, labour productivity, yields and production per capita of food grains stagnated or declined up to the end of the 1990s. Some causes of this failure are discussed.     

Achievements and gaps in tef productivity improvement practices in the marginal areas of Northern Ethiopia: implications for future research directions

Tef is the most important crop in Ethiopia and is well-adapted to growing environments, but grain yields are low. The government is therefore promoting the adoption of improved varieties, inorganic fertilizers and new planting techniques. This study gathered information on the use of new agronomic practices and barriers to their adoption through a semi-structured questionnaire administered to 60 farmers or respondents from each of 4 districts of Tigray region in northern Ethiopia viz Laelay-Maichew, Medebay-Zana, Ahferom and Alamata. Data were coded and analysed using SPSS software. Except for animal feed and crop rotation, there were significant differences between districts in the relative importance of several criteria for different uses. Improved varieties were used by the majority of respondents in all districts and fertilizers in all except Alamata where severe moisture stress dictated the choice of variety and reduced fertilizer application. Weed control was mainly by hand except in Alamata where chemical control was common because of the predominance of broad-leaved weeds. Transplanting maximized the yield of tef, but a cost–benefit analysis showed that row sowing was more profitable. The study concluded that new varieties better adapted to the likelihood of reduced rainfall and that respond efficiently to fertilizer inputs need to be developed. Until suitable technologies are available, high labour costs would in part dictate some agronomic practices, even if this led to lower yields.     

Duration Analysis of Technological Adoption in Ethiopian Agriculture

Duration analysis has been used to examine the impact of time‐varying and time‐invariant variables on the speed of adoption of fertiliser and herbicide by smallholder farmers in East and West Shewa in the central highlands of Ethiopia in the 25 years preceding 1996. The estimated models suggest that economic incentives were the most important determinants of the time farmers waited before adopting new technologies; traction power in the form of oxen and infrastructural factors (in particular proximity to markets) also appear to have been important influences, but less so than prices. Other agricultural inputs (area of farmland, labour, credit), extension services and farmers' personal characteristics (education, gender, age) appear to have had little, if any, effect on adoption behaviour. There is also evidence that the speed of adoption of herbicide, on both tef and wheat, was slower than that of fertiliser.     

Sustainable urban agriculture and the adoption of composts in Cameroon

The increased importance of urban agriculture in developing countries suggests reconsidering some innovation adoption opportunities and challenges, particularly soil fertility inputs. In sub-Saharan Africa, urban horticulture uses a high level of soil inputs like inorganic fertilizers, while local composts are far less common. Yet, municipal solid wastes provide high quantity of organic matter, a major component of compost. Our study aimed to determine if urban horticulture in sub-Saharan towns can provide incentives for compost adoption among farmers. To this end, we surveyed 242 farmers in Yaoundé, the capital of Cameroon in the Central Province, and in Bafoussam, a city in the West Province. We used an Ordered Logit Model to test four soil input modalities adopted by farmers and ranging from no soil inputs, composts only, composts and inorganic fertilizers, and inorganic fertilizers only. Our results revealed that 36% of farmers adopt an exclusive or mixed use of compost. Inorganic fertilizer expenditures, vegetable production, land ownership, and land distance simultaneously and significantly influence the four soil input alternatives. Urban horticulture provides the prerequisites for compost adoption in sub-Saharan Africa. We suggest several recommendations for implementation of a waste recycling commodity chain dedicated to agriculture.     

Land management,erosion problems and soil and water conservation in Fincha’a watershed,western Ethiopia

The knowledge of soil erosion processes, attitude towards rational use of resources and institutional support affect the capability of farmers to implement soil and water conservation (SWC) measures. This research was conducted to determine soil erosion problems and the factors that affect the adoption of SWC measures in Fincha’a watershed, western Ethiopia. A total of 50 farmers were interviewed using a semi-structured questionnaire, and two group discussions were held with 20 farmers. Moreover, transects were walked to classify erosion features, and a quantitative erosion survey was made on 19 farm plots during the rainy season of 2004. The results showed that crop fields are affected by annual soil losses ranging from 24 to 160 Mg ha⁻¹. Farmers are well aware of these erosion problems, and related the soil loss to steep slopes and a decline in soil fertility. However, they did not invest much in SWC measures, but apply soil management practices to sustain crop yields. The wealth status of farmers, land tenure arrangements and lack of access the farmers have to information are the major factors affecting SWC adoption. High labour demand of SWC measures, lack of short-term benefits and free grazing have negatively affected SWC adoption. Soil erosion problems in Fincha’a watershed have both on-site and off-site effects that require integrated SWC planning at watershed scale.     

Evaluating Agricultural Energy Policies Under Uncertainty: The Case of Electricity in South India

Farmers' attitude towards risk associated with the availability of energy inputs will influence their investment behavior and demand for energy inputs. In order to analyze policies that reduce the risk in energy availability, some modifications in methods are required. This study, using a mean-variance framework, demonstrates how cross-sectional data and time-series data on crop yields and prices can be used to analyze agricultural energy policies under uncertainty in a developing country context. It is argued that the farmers risk attitudes, their crop allocation behavior, changes in the demand for energy inputs and the stochastic relationship between various forms of energy inputs can be explained by the various energy constraints faced by them. Furthermore, using the same methods the impact of policies which affect these constraints, can be analyzed.     

The political ecology of rice intensification in south India: Putting SRI in its places

The system of rice intensification (SRI) has been promoted across Asia as a means to improve rice yields while decreasing water use and external inputs. It is argued to be a generalisable means by which to revalidate smallholder livelihoods and improve food security across the region. Current debates about SRI, however, remain predominantly technical in scope, focusing on field‐level outcomes. To more adequately understand the potential of SRI for smallholder farmers, we argue that it is necessary to situate SRI within a political ecology framework that addresses how the adoption and practice of SRI is shaped by uneven access to key assets including labour, water, and extension networks. Fieldwork conducted in Mahabubnagar district in Telangana, south India—where SRI had been widely disadopted despite the achievement of higher yields—is used to illustrate why agronomic analysis must engage directly with the complex social contexts in which farmers operate.     

Exploring farmer perceptions of agricultural innovations for maize-legume intensification in the mid-hills region of Nepal

Maize-legume intercropping is a fundamental component of mixed farming systems in the mid-hills of Nepal. However, its productivity is constrained by several biophysical and social factors, and limited adoption of proven agricultural innovations. In this study, we assessed the productivity impact of a selection of relevant agricultural innovations and changes in the associated perceptions of farmers through a series of two-year participatory on-farm trials. The evaluated innovations resulted in higher yields as compared to farmers' current practices. The active involvement of farmers enlarged our understanding of underlying decision-making factors to adopt or non-adopt agricultural innovations. Additionally, the in-depth farmer engagement in our onfarm trials positively influenced farmer perceptions of the innovations and their interest to adopt the agricultural innovations. Yet, farmers final decisions to adopt some of the evaluated innovations were limited by a host of factors including labour scarcity, the availability of inputs, and by cultural preferences despite the increased yields. This was particularly true for low and medium resource-endowed farmers. This study shows the importance of active farmer participation and context-specific design of research and development projects aiming for local impact.     

Integration of conservation agriculture in smallholder farming systems of southern Africa: identification of key entry points

A component-omission experiment based on the principle of conservation agriculture (CA) was established on smallholder farms for three seasons in Murehwa and Hwedza districts, Zimbabwe; Barue district in Mozambique; Balaka district and Chitedze Research Station in Malawi, and Monze district in Zambia to identify strategies for improving crop productivity and livelihoods for smallholder farmers. The objective of the experiment was to evaluate the effect of tillage, residue retention, fertiliser application and weed control on maize yield. In addition, the study analysed possible combinations of these factors that could provide a sustainable entry point for intensification through CA. Results showed that fertilisation had the strongest effect on crop yield in both tillage systems; adequate fertilisation is therefore key to success in CA. Retention of crop harvest residues increased yield in no-tillage systems; no-tillage without residues depressed yield by 50% when compared with yields of conventional tillage. A step-wise integration of CA into the smallholder farming systems is proposed as a possible strategy to avoid new constraints on smallholder farms. If resources are limiting, farmers may apply all principles on small areas to overcome the initial demand in resources (labour, fertiliser and residues), and once productivity is raised, they can expand.     

Agricultural technology and land use futures: The UK case

This paper explores how agricultural technology has interacted with recent land use in the UK and how it might do so in the next 50 years. From 1960 to 1985, farmers successfully used technology to increase the output of crop and animal products per unit of land and particularly of labour. This reduced the number of people employed in agriculture, and promoted larger and more specialised farm enterprises. Between 1985 and 2006, food prices were relatively low, and although labour productivity continued to increase, land productivity remained relatively static. However during this period, farmers started to address the effects of agriculture on reduced water quality and habitat loss.For established agricultural products, technological innovation tends to have an incremental effect, working through genetic improvement, the removal of abiotic and biotic stress (e.g. crop nutrition and protection, irrigation and drainage, and animal nutrition, health and housing) and the substitution of labour. Whereas the first two processes tend to be scale-neutral, the substitution of labour is usually easiest to achieve on larger farms. Other key areas for technological innovation include addressing air, soil and water quality, biodiversity, waste reduction, and information management. Over the next 50 years, large step-changes in land use arising from agricultural technology are predicted to arise from the development of new markets for agricultural products. A strong bioenergy sector will strengthen the links between crop commodity and energy prices and will have a major effect on future land use. Climate change and the regulation of greenhouse gas emissions will alter the relative profitability of crop and animal production systems. Lastly, increased public awareness of the links between food, health and the environment could substantially shift the demand for specific agricultural products.Continual improvements in agricultural technology are pivotal to providing society with the flexibility to balance the challenges of improving human well-being with the management of the planet's ecosystem. Increased technological innovation increases the probability that agricultural land can be used for other purposes, but the exact relationship is dependent on trade and environmental policies. The large external effects of agriculture mean that decisions regarding the adoption of future technologies should be taken by farmers working with other stakeholders.     

Awareness and adoption of conservation agriculture in Malawi: what difference can farmer-to-farmer extension make?

Despite the potential of conservation agriculture (CA) for increased crop yields, energy savings, soil erosion control, and water-use efficiency, smallholder farmers in sub-Saharan Africa have been slow to adopt. Farmer-to-farmer extension (F2FE) may have a role to play in overcoming the information access problems and lack of knowledge that may preclude widespread adoption. This study uses data for 180 lead farmers linked to their 455 followers to investigate how F2FE influences awareness and adoption of CA technologies in Malawi. Results from a bivariate probit model for follower farmer awareness and adoption of the three CA principles (minimum soil disturbance, crop residue retention, and crop diversification) reveal four main findings: First, lead farmer motivation increases their effectiveness at diffusing CA practices to their followers. Second, lead farmer familiarity with and adoption of CA both matter to the spread of CA practices, but familiarity appears more important. Third, lead farmers play a more critical role in increasing awareness than adoption of the CA practices. Finally, F2FE is a complement rather than a substitute for other sources of agricultural extension in Malawi's pluralistic extension system and should support but not replace current systems. Research and policy implications are discussed.     

Negative evaluation of conservation agriculture: perspectives from African smallholder farmers

Despite more than three decades of promotion, conservation agriculture (CA) has not been widely adopted by smallholder farmer in sub-Saharan Africa. This low rate of adoption reflects substantial negative evaluation of CA by many smallholder farmers, the causes of which have not been adequately explored in an in-depth, qualitative manner. Hence, we implement the Livelihoods Platforms Approach to explore directly with negatively evaluating farmers the reasons why they chose not to implement CA using semi-structured interviews with 35 farmers from 23 communities in 6 African countries. While there are issues with perceived benefit and relevance, the primary driver of negative evaluation of CA was found to be the feasibility of implementation. The required resources to implement CA (financial, physical, human and informational) are limited by community and institutional constraints which appear unlikely to be overcome through interventions targeted at addressing household resources. More positive evaluation of CA by smallholder farmers requires: (1) development of financially viable CA adoption pathways; (2) incorporation of wider livelihood objectives into a CA ‘package’; (3) re-evaluation of current extension policy; and (4) development of CA-complementary agricultural policies. Without addressing these issues, the potential benefits of CA adoption are unlikely to be achieved in African smallholder systems.     

Harnessing sustainability,resilience and productivity through conservation agriculture: the case of likoti in Lesotho

Subsistence farmers in Lesotho have been able to boost agricultural yields and increase food production by adopting conservation agriculture. The practice, locally known as likoti, also contributes to combating soil erosion and to enhancing fertility. The socio-economic and environmental benefits help poor households to rehabilitate and strengthen their livelihood capital base and ultimately help rural communities to build system resilience in the face of widespread poverty and increasing vulnerability that affect the country. This paper discusses the major advantages associated with the spread of likoti. By drawing on primary data collected by FAO-Lesotho, it enquires into the determinants of adoption, thereby highlighting constraints and options for future up-scaling. The results show that attending appropriate training is a crucial prerequisite for the correct adoption of likoti. However, training is more effective when trainers pursue true participation and when social capital among farmers is stronger. Further important determinants of adoption are the level of education and the economic incentives provided to vulnerable households. Stronger policy and institutional support in all these areas would thus help address the cultural and resource constraints that limit the full potential of likoti to be harnessed and ultimately hinder its further spread throughout the country.     

Land titling policy and soil conservation in the northern uplands of Vietnam

In Vietnam, a quasi-private property regime has been established in 1993 with the issuance of exchangeable and mortgageable long-term land use right certificates. Using primary qualitative and quantitative data collected in a mountainous district of Northern Vietnam, this paper investigates the role of the land policy in the adoption of soil conservation technologies by farmers. This issue is of crucial importance in the region where population growth and growing market demands have induced farmers to intensify agricultural production. While poverty has been reduced, environmental problems such as soil erosion, landslides, and declining soil fertility have become more severe over the past years. Our findings suggest that despite farmers’ awareness of erosion, soil conservation technologies are perceived as being economically unattractive; therefore, most upland farmers continue to practice the prevailing erosion-prone cultivation system. Focusing on agroforestry as one major soil conservation option, we estimate household and plot-level econometric models to empirically assess the determinants of adoption. We find that the possession of a formal land title positively influences adoption, but that the threat of land reallocations in villages discourages adoption by creating uncertainty and tenure insecurity. The analyses reveal that these two effects interact with each other but are of small magnitude. We conclude that the issuance of land titles is a necessary but not sufficient prerequisite to encouraging the adoption of soil conservation practices. However, current practices remain economically unattractive to farmers. This deficiency needs to be addressed by interdisciplinary research and complemented by strong efforts by local authorities to promote sustainable land use.     

Sustainable agricultural intensification: the role of cardamom agroforestry in the East Usambaras,Tanzania

The East Usambaras in Tanzania are a tropical biodiversity hotspot where current agricultural management practices pose threats to forest conservation and development objectives. Promoting sustainable agricultural intensification (SAI) would improve long-term productivity and reduce pressure on forest reserves. The study objective was to identify household-level characteristics that influence adoption of improved management practices, specifically soil replenishment practices, in order to identify opportunities and constraints to scaling up SAI to landscape level. First, three common farming systems and a fourth agroforestry (AF) model were developed to estimate the relative profitability of incorporating fallow, manure, and non-timber forest product activities. Next, household surveys were conducted and a logistic regression analysis was used to measure the influence of socioeconomic characteristics, physical and financial assets, tenure security, and plot-specific attributes on adoption of soil replenishment practices that were specified in the model. Findings showed that the AF model was financially competitive but raises opportunity costs to labour when compared to common systems. Marital status, household size, remittances, credit access, and tenure security significantly influenced adoption of fallow and applying organic inputs. Significant plot-specific attributes included perceived fertility and distance from the homestead. Policies to scale up SAI should consider these factors and emphasize improving markets for AF species and extension services.     

WORLD AGRICULTURAL TRADE AND THE NEW GATT ROUND

World agricultural markets are grossly imbalanced with supplies running well ahead of demand at current depressed world prices. At the heart of the problem is the high protection given to agriculture in many OECD countries. In particular, price supports to farmers are too high and incentives to maintain or expand production too great. The success of the Uruguay Round in achieving greater liberalisation of trade in agriculture will depend on the willingness of participating governments to undertake significant reforms of domestic agricultural policies, with the aim of reducing overall protection to agriculture and switching support measures away from direct producer price support to income aid for specific disadvantaged producers. In some countries, this notion has run up against complex politico-social and structural objectives, which prevent these countries from agreeing to any significant price reduction. Price support policies, however, have been ineffective in the long run in retarding the outmigration of labour from agriculture. Measures involving only quantitative controls on production will be useful in the short run to reduce surpluses but will not solve the underlying problems which the new GATT Round must address.