Semi-arid West Africa is one of the regions of the world where rural poverty and food insecurity are of highest concern. The productivity of crop–livestock systems in this region is greatly hampered by inadequate availability of nutrients (i.e. metabolizable energy, protein and phosphorous for livestock production; and organic matter, nitrogen and phosphorous for crop production). Growth in human and livestock populations has led to an expansion of cultivated land and shortened fallow periods. This, in turn, has accelerated land degradation and decreased soil fertility. At the same time, low rural incomes, inappropriate public policies and infrastructure constraints have prevented the widespread use of purchased inputs such as inorganic fertilizers and feed supplements.
In response to increasing pressure, farming systems in the region are evolving towards more integrated forms of crop and livestock production. Livestock production depends on the quantity and quality of available forage, which, in turn, depends on soil fertility and land use (among other factors). In the long term, soil fertility in cropped or fallow fields is a function of the balance between nutrients added to the soil and nutrients removed through crop harvesting and grazing. Thus crop and livestock production are highly interdependent. This explains why land degradation, low productivity and rural poverty result when management schemes do not respond to demographic pressure or drought. However, this interdependency also provides an avenue for improving soil fertility, and thereby increasing agricultural production and the well-being of rural dwellers.
The general objective was to increase the productivity of crop–livestock farming systems of semi-arid West Africa through better nutrient management.
Specific objectives included to:
- assess, ex ante, the potential impact and acceptability to farmers of technical alternatives for nutrient management, integrating animal manure, crop residues, legumes, fodder or inorganic materials;
- improve farmer incomes by increasing meat and milk production and the supply of nutrients for soil improvement through better use of available resources;
- improve the efficacy of livestock-mediated nutrient transfers within village territories through better land use and institutional arrangements; and
- promote the adoption of nutrient management interventions through the identification of appropriate economic incentives and policy options.
Development of improved nutrient-management packages
Diagnostic studies to identify research sites and develop nutrient-management techniques to improve livestock nutrition and the availability of soil nutrients were conducted. The adoptability of technical packages were assessed based on ex ante evaluation of the outcome of the diagnostic studies to provide information on the economic viability of prospective interventions.
Increased food crop and fodder production and maintenance of soil fertility
The programme examined options for increased farm productivity through efficient use of farm residues, animal manure, local phosphate rock and purchased fertilizers.
Improvement of the efficacy of livestock-mediated nutrient transfer
This research evaluated alternative land use and livestock management
options on natural vegetation within village territories. Impact was assessed
using specially developed Geographical Information System (GIS)-based
models.
Main
lessons learned from the project:
- Low-cost implements suitable for manure collection and spreading, and appropriate institutional arrangements to strengthen complementary interactions between farmers and herders, will improve manure utilization (Figure 1), soil fertility and food production.
- External sources of nutrients (such as nitrogen and phosphorus fertilizers, and feed supplements) are required to render the system more productive and sustainable.
- Supplementing village livestock (Figure 2) with cereal grain by-products and minerals not only improves their performance but also increases the concentration of nutrients in faeces and urine.
-
Locally
available forages (Figure 3) and crop residues (Figure
4) could partly substitute for the industrial by-products generally
advocated as feed supplements for livestock. - The use of crop residues is particularly relevant to improving the performance of animals owned by women (Figure 5).
-
Research
should enhance its “low external input” strategy, by linking
more closely to available research results in the field of agroforestry
(i.e. optimal fodder producing species and productive arrangements identified
by the International Centre for Research in Agroforestry (ICRAF)). 
A key issue identified was that of matching farmers’ nutrient
management experience and range of possibilities with the inputs –
physical or knowledge-
based – that can effectively be supplied
on a sustainable basis by external agencies.
