Soil fertility and nutrient dynamics under conservation agriculture in the semi-arid region of Burkina Faso

This study investigates the impact of Conservation Agriculture (CA) on soil fertility and nutrient dynamics in the semi-arid region of Burkina Faso, an area plagued by soil degradation and declining agricultural productivity. The primary objective was to assess the long-term effects of CA practices, including no-tillage, crop residue retention, and crop rotation, on soil fertility and the cycling of major plant nutrients such as nitrogen (N), phosphorus (P), and potassium (K). We compared the soil fertility status and crop productivity under CA and Conventional Tillage (CT) systems in a field-based experiment over a four-year period. Soil samples were collected from depths of 0-15 cm, 15-30 cm, and 30-60 cm for analysis of soil organic carbon (SOC), total nitrogen, available phosphorus, cation exchange capacity (CEC), and other soil parameters. Crop yields of millet and sorghum were also monitored to evaluate the impact of CA on agricultural productivity. Statistical analyses, including ANOVA and Pearson’s correlation, were performed to compare the results between the two systems. The results revealed a significant increase in SOC, nutrient availability (N, P, K), and crop yields under the CA system, particularly in the topsoil (0-15 cm). Soil organic carbon content increased by 77%, and crop yields of millet and sorghum showed a 50% and 31% increase, respectively, under CA compared to CT. However, nutrient stratification was observed at deeper soil layers (15-30 cm and 30-60 cm), where nutrient levels were significantly lower. These findings highlight the effectiveness of CA in improving soil fertility and crop productivity but also underscore the challenges related to nutrient stratification in semi-arid regions. This study concludes that while CA has significant short-term benefits for improving soil fertility and crop yields, further research is needed to address nutrient stratification and optimize management practices for long-term sustainability.