Improvement in physical quality of a Sahelian Arenosol and implications on millet yield

Poor soil fertility remains a threat to crop production and livelihoods in the Sahel. Understanding the impacts of proposed soil fertility management technologies on soil fertility status and millet yield is essential. We conducted a 2-year experiment to assess changes in selected physical properties of an Arenosol and their impacts on millet yields at Karabedji, Niger. Treatments consisted of four fertilizer rates applied on top and bottom farm types selected from a long-term experiment. Mixed-model analyses indicated considerable effects (P=0.055) of fertilizer rates and farm types on soil structural stability being higher in the top farm than in the bottom farm type. Dexter's soil physical quality index (S) varied significantly with soil depth. A significant correlation (R-2=0.24) was found between the aggregate stability index and S. Plant available water recorded in fertilizer-treated soil was higher than the control and higher on the top farm than in the bottom farm. Fertilizer rates and farm types influenced millet yields. Moreover, we obtained positive relationships between millet yield and soil aggregate stability, and plant available water, thereby elucidating the significant role played by soil physical properties in influencing crop yields. S can be a simple way for assessing the physical quality of Sahelian sandy soil