Contribution to soil fertility level assessment in cotton-based cropping systems in Benin

Abstract

Cotton is the main cash crop cultivated in Benin. The continuous increase in cultivated areas has led to more sedentary agricultural system, followed by soil degradation and crop yield decline. This study aimed to assess soil fertility grade in the cotton belt of Benin. Thirty soil samples were collected, each from a cotton farm, for thorough physical and chemical analyses. Results showed that soil texture is mostly sandy-loam, with only 7.38-12.65% clay. Sand percentage ranged from 60 to 80%. Nitrogen (N) content varied from 0.055 to 0.076%, while soil pH was about 5.7-6.5. Soil Organic Matter (SOM) content was between 1.20 and 1.52%. The sum of the exchangeable cations ranged from 3.98 to 6.98 cmol+/ kg and the cation exchange capacity (CEC) ranged from 5.35 to 7.91 cmol+/ kg. Available Phosphorus (P) content was estimated at 5-13 cmol+/kg. By and large, the soils surveyed showed good physical properties, but they were chemically poor. Therefore, the inherent fertility level was low, which put their sustainable use at risk. The main target is to raise the pH and SOM content, through organic and mineral amendments.