Assessment of past and present soil conservation initiatives in Nigeria

摘要

In Nigeria, soil degradation has been one of the most critical environmental problems for a long time. Hence, there has been and still is an urgent need to develop effective soil resource management systems that can reverse the trend and sustain soil productivity to enhance food security and alleviate poverty. An extensive literature search that started in 2006 has shown that soil conservation has a long tradition and earlier and present initiatives have resulted in various so-called on-farm and off-farm technologies. Indigenous techniques focused on soil and water conservation by ridging, mulching, constructing earth bunds and terraces, multiple cropping, fallowing, and the planting of trees. In colonial times, large-scale projects on soil loss control were started by the British Government but many failed, as the imported technologies had little relevance in the tropics. After independence, more emphasis was put on soil fertility issues. Decreasing funds at the end of the oil boom in the 1980s also restricted soil conservation schemes. The review also revealed that most of the projects on soil conservation were carried out on research farms and only a few on-farm with the participation of farmers. As these have rarely been evaluated to establish adoption rates, an assessment study was performed in 2007 to analyze the effectiveness and adoption of past and present soil conservation initiatives, including the sociological, technological, and economic aspects. Villages with different types of conservation technologies were visited and farmers in southwest Nigeria were interviewed to obtain information on their experiences. Mulching, cover cropping, and contour tillage are likely to be effective on-farm soil conservation measures practiced in Nigeria. They are generally adopted by farmers as they are compatible with the existing farming system, cheap and easy to install and to maintain. Agroforestry is not popular and cut-off drainage is often rejected as it is culturally incompatible. Education, knowledge on soil conservation, labor availability, and membership in organizations have a positive influence on the adoption rate of technologies.