The last 50 years have seen a rapid expansion of cultivated area in semi-arid areas of West Africa. This has precipitated a change from traditional fallowing to more pro-active soil fertility management techniques. Smallholder farmers employ a range of technologies to enhance soil fertility and manure is a cornerstone of many of the soil fertility management strategies they use. This paper reviews manure management by smallholder farmers. It considers factors that affect the quality of the manure used, including methods for keeping livestock and storing manure. The paper reviews the strategies, such as night parking and crop-livestock integration, which farmers employ to ensure that manure reaches their fields. The nutrient balances of two farming systems are presented as evidence for the importance of manure as a nutrient source. Rangeland-to-cropland nutrient transfers are contrasted with nutrient recycling through crop-livestock integration. The paper concludes that within the constraints in which smallholder farmers operate in semi-arid West Africa, manure will remain an important component of soil fertility management strategies for the foreseeable future. Integrated nutrient management strategies that take into consideration the circumstances of farmers, and the resources available to them, are the best way forward. Appropriate interventions need to focus on improving manure management to ensure that the material which farmers so laboriously prepare and transport is of the best possible quality.

Donors have invested more than US$45 million in seed production projects in Niger during the past two decades. These investments have largely failed. Public seed systems consistently supplied less than 2% of the total national seed planted by farmers. Through subsidies, seed prices represent less than one-third of the average cost of seed production. In contrast, at the village level, most farmers consistently obtain pearl millet (Pennisetum glaucum) seed from their own harvests, from neighbours or from village markets. Seed is of acceptable quality and a range of varieties is available. Village seed systems offer a cheaper and more efficient means of delivering seed to farmers. Future investment in seed systems development should target improvements in the capacity of village seed systems to maintain and distribute seed security stocks in drought years. Efficient seed producers or groups of farmers in each community should be identified and encouraged to become entrepreneurs tasked with the multiplication and distribution of new pearl millet varieties.

Soil fertility constraints to crop production have been recognized widely as a major obstacle to food security and agro-ecosystem sustainability in sub-Saharan West Africa. As such, they have led to a multitude of research projects and policy debates on how best they should be overcome. Conclusions, based on long-term multi-site experiments, are lacking with respect to a regional assessment of phosphorus and nitrogen fertilizer effects, surface mulched crop residues, and legume rotations on total dry matter of cereals in this region. A mixed model time-trend analysis was used to investigate the effects of four nitrogen and phosphorus rates, annually applied crop residue dry matter at 500 and 2000 kg ha−1, and cereal-legume rotation versus continuous cereal cropping on the total dry matter of cereals and legumes. The multi-factorial experiment was conducted over four years at eight locations, with annual rainfall ranging from 510 to 1300 mm, in Niger, Burkina Faso, and Togo. With the exception of phosphorus, treatment effects on legume growth were marginal. At most locations, except for typical Sudanian sites with very low base saturation and high rainfall, phosphorus effects on cereal total dry matter were much lower with rock phosphate than with soluble phosphorus, unless the rock phosphate was combined with an annual seed-placement of 4 kg ha−1 phosphorus. Across all other treatments, nitrogen effects were negligible at 500 mm annual rainfall but at 900 mm, the highest nitrogen rate led to total dry matter increases of up to 77% and, at 1300 mm, to 183%. Mulch-induced increases in cereal total dry matter were larger with lower base saturation, reaching 45% on typical acid sandy Sahelian soils. Legume rotation effects tended to increase over time but were strongly species-dependent.

Land degradation is one of the major problems related to low productivity in Ethiopia. Vertisols are potential agricultural lands but are underutilized due to waterlogging during the rainy season and are prone to soil erosion due to the traditional practices of planting crops at the end of the rainy season exposing bare land to heavy rains. An animal-drawn implement, the broadbed maker (BBM), was tested to facilitate drainage of the Vertisols. Improved drainage enables earlier planting of crops to use the resultant prolonged growing period for attaining higher yields. In order to further improve the BBM package, the frame of the BBM was used for attachment of other implements to minimize tillage practices and reduce seed and fertilizer rates, labour and animal power requirements and soil erosion. The attachments were tested both on-station and on-farm with positive results.

Combined socio-economic and agronomic surveys were conducted during two growing seasons with 20 rice (Orgyza sativa) farmers in the irrigation scheme of Guédé, northern Senegal. Farmers' knowledge of recommended cropping practices was relatively poor. The surveys identified sub-optimal timing of N fertilizer application and late harvesting as major constraints. Before the start of the second season, farmers were given field-specific recommendations on timing of key crop-management interventions. Average yield compared with the first season increased by more than 1 t ha−1, which was attributed to a slightly higher recovery efficiency of fertilizer N (REN) (average: 0.47 kg crop N kg−1 fertilizer N), a change in cultivars used (resulting in a better uptake of indigenous soil N) and more favourable weather conditions in general. It is concluded that if farmers are given better access to information, improved rice technologies, inputs and decision making, rice production on irrigated land in West Africa may leap forward rapidly, as potential production gains are still large.

Farmers hosted on-farm trials and demonstrations involving three new groundnut (Arachis hypogaea) varieties in Malawi to assess their acceptability and adoption potential. Patterns of seed diffusion among trial farmers were examined as well as among non-trial farmers who were members of seed banks. The study showed that trial follow-up surveys provide a cost-effective approach for assessing early adoption and providing feedback to researchers. While useful, however, such studies are not an end in themselves. Rather they need to be perceived and designed as one of several studies that help researchers understand the complexity of farmers' adoption decisions.

The duration of the residual effect of sesbania (Sesbania sesban) fallow on subsequent crops will determine the interval at which sesbania must be grown to replenish N in a planted fallow–crop rotation cycle. An experiment was conducted from 1995 to 1998 (seven cropping seasons) on two farms in western Kenya, an area subject to a bimodal annual rainfall pattern. The aim was to compare the effect of a single-season sesbania fallow with continuous annual cropping with and without phosphorus fertilizer, on a P-deficient soil. Phosphorus was applied at a rate of 500 kg ha−1 in a single application to meet the phosphorus needs of subsequent crops for the next five to ten years. Sesbania was established simultaneously with maize by direct seeding in the first rainy season of 1995 and allowed to grow as a pure fallow through the second rainy season. Following the harvest of this fallow crop, sole maize in the first post-fallow season and maize-bean intercrops in the subsequent four seasons were grown with and without nitrogen at a rate of 100 kg ha−1. Added phosphorus on average increased maize yields by 3.7 times over the control, indicating that phosphorus fertilizer is essential for good yields. The amount of phosphorus recycled by sesbania fallow was inadequate to meet the crop needs in P-deficient soils. While continuously cropped maize in the presence of phosphorus responded to nitrogen in all seasons, the crop following sesbania responded only from the third season. In the first post-fallow season, sesbania increased maize grain yields over continuous maize by 1.4 t ha−1 with phosphorus fertilizer and by 1.3 t ha−1 without phosphorus fertilizer. The residual effect of sesbania with phosphorus fertilizer lasted for two seasons, while without phosphorus it lasted for only one. In these Kenyan highlands, farmers who can afford fertilizer should buy phosphorus fertilizer and rely for nitrogen on planted fallow with species such as sesbania grown for one season every two years. For farmers who cannot afford fertilizer, one-season fallow every year may be more attractive because of labour savings and the firewood produced by sesbania.

Wheat (Triticum aestivum) production using no-tillage is becoming an increasingly accepted management technology. Major obstacles to its adoption in Morocco, however, are exportation of wheat straw from the field and stubble grazing. Among pertinent solutions is the control of these practices. A four-year field study was conducted to determine the effect of residue level under no-tillage on wheat grain and total dry-matter yields, water use and water-use efficiency, and to compare this with conventional tillage systems. The aim was to evaluate whether all the straw produced is needed for no-till cropping or whether partial removal of straw from the field is possible without any adverse effect on production. No-tillage and deep tillage with disk plough performed equally well and subsurface tillage with an off-set disk produced the lowest yields. Both bare and full no-tillage covers depressed wheat production. Uo to 30% of straw produced under no-tillage can be removed without jeopardizing wheat crop performance.