Current soil fertility management practices and their effects on the cotton production and soil on the cotton farms of Central and Western Burkina Faso

摘要

Sustainable soil management is a major concern for cotton farms in Burkina Faso due to population growth, the expansion of cotton cultivation and suboptimal practices of soil fertility management. The study of these practice and the evaluation of their impacts on soil and cotton production was performed in the centre and west of Burkina Faso. The analysis of practices and their impacts were implemented by surveys at 315 farms and the evaluation of agronomic and soil impacts was conducted in each cotton zone on 45 fields. We identified soil and water management practices, as well as crop rotation practices of variable proportions according to the natural assets of each cotton zone. In the western and central cotton zones, six and seven fertilization regimes were identified, respectively. These fertilization regimes were often lower than the recommendations formulated by the cotton companies. On an average, they involved a decrease in yield from 20-40% in the Centre and 35 to 90% in the West. Only the organo-mineral fertilizations increased yields by 14-25% and 6-33% respectively in the Centre and West compared to mineral fertilization. Application of organo-mineral fertilization led to the highest soil nutrient contents (total carbon, total nitrogen). The optimal duration of cultivation fields is 10 years in the cotton zone. Beyond 10 years, cotton yields and soil nutrient contents decline. Among tillage systems, both animal and motorized ploughing are suitable for the Central zone. In the West, minimum tillage better preserves soil fertility but with low yields. Current farming practices of soil fertility management in the cotton zones are not favourable to the sustainable increase of crop production. However, the soil conservation and water techniques and the use of organo-mineral fertilizers are the germs of a better integrated and a more sustainable management of productive capital.