Agricultural extension plays a significant role in the development of agriculture in developing regions of the world since it provides a channel through which challenges facing farmers can be researched upon and modifications made to policies upon recommendation. Agricultural extension is described as the application of scientific methods such as research and knowledge to agricultural practices through education and training of farmers. A framework is provided, through which farmers are organized into functional groups. These groups make it easier for individual members to access credit, inputs, market services, and information. Furthermore, extension services draw farmers’ awareness to use of modern technologies and techniques, essentially boosting yields. Extension services are classified into three categories; technology transfer, advisory, and facilitation.
Soil productivity and Soil fertility
Soil productivity refers to the capacity of a soil in its normal environment to produce a plant or crop sequence under a specified system of management. It is affected by climatic factors such as temperature, precipitation, humidity, light, altitude, wind and carbon dioxide concentrations. Soil factors such as texture, structure, topography and organic matters also influence productivity. Recent research and evaluation of the quality of the soil resource base of Africa reveal that 55 per cent of the land is unsuitable for agriculture and largely comprises of deserts that are not suitable for any kind of agriculture except nomadic grazing.
To establish a soil’s productivity, an index is used to rate the potential yield of one soil against another over a given period. Ratings vary from 0 to 100.
Soil fertility is the capacity of the soil to supply the plant with required nutrients for growth. It is a complex quality of soils that is closest to plant nutrient management. It is a manageable property of soils and is fundamental to achieving sustainable crop production. Fertile soils are usually productive but not always. It is possible for soil to be fertile but not productive. A soil test is carried out to establish fertility. Tests are designed to establish the soils ability to supply a particular nutrient. Modern tests usually check for potassium and phosphorous concentrations. High test readings indicate a soil has greater ability to supply the nutrient and will, therefore, need less fertilizer. Low readings determine that the soil requires an additional supply of nutrients. The rate of supply of a nutrient at a test is determined by calibration trials with different rates of fertilizer to determine crop response.
There have been diminishing returns of produce from farms in Africa. Subsistence farming feeds more than half of the population in Africa. However, farmers have had minimal input in acquiring and managing information about their soil’s resource condition. Research has shown that for example in Asia, that green revolution is successful in areas where there are serious efforts to match technology with resource conditions and where advance in development and use of high yielding cultivars was accompanied by appropriate soil, water, and nutrient management. Considering the foregoing, focus has shifted to the role of extension services in Africa in a bid to improve agriculture to sustainable levels.