Alley Cropped Gliricidia sepium (Jacq.) Kunth ex. Walp. Enhance Soil Fertility and Yields of Cotton, Maize and Sorghum in Mali

Mineral fertilizers are effective in boosting crop yields in most parts of the world. Under tropical conditions and especially in rain-fed arid ecosystems they are not effective, because the limitations of system productivity are stronger at the level of the climatic situation and soil quality. The positive effect of Glirici-dia sepium (G. sepium) for: erosion control, shade, hydraulic lift, N-fixation, resource of fodder and soil input convinced the participating farmers to provide part of their land for this study. G. sepium was tested in association with cotton, maize and sorghum in order to develop best practices at two research stations and on fields of 30 farmers in the Sudanese and Sudano-Guinean zones of Mali. In addition to the introduction of G. sepium, the effects of organic and mineral ferti-lizers we tested at recommended and half rate. On-station experiments design was a split-plot with four replicates. The pH, soil organic carbon and nitrogen in soil samples were analyzed from 0-20 cm depth taken in 2016 at the beginning of the experiment and in 2018. The average yields of cotton, maize and sorghum associated with G. sepium were 812, 1,457 and 1,377 kg ha-1 respectively, whe-reas they were significantly lower without G. sepium reaching only 623, 1,014, and 807 kg ha-1 respectively. In the third year after planting G. sepium, organic carbon contents and total soil nitrogen increased by 5% in soils between the al-leys. Association of G. sepium with cotton, maize, and sorghum showed the im-provement of crop yields and soil nitrogen content in addition to other advantag-es not considered for testing here. This finding may serve to improve small-scale farmer’s livelihoods status through the improvement of soil fertility in Mali and the whole Sahel region.