Farming practices and their effect on soil moisture and penetration resistance: Impact on maize yields in rainfed agriculture

In sub‐Saharan Africa, there is growing interest in conservation agriculture practices, including reduced tillage (e.g., ripping), residue retention, and crop diversification, but their effects on soil moisture and penetration resistance in sub‐humid regions remain unclear. This study investigated the effect of ripping, residue retention, cropping systems, and fertilizer management on soil moisture, penetration resistance, and maize ( Zea mays L.) grain yield in a sub‐humid zone of western Kenya. The study was conducted in a long‐term experiment in western Kenya, using a split‐split‐split plot design with tillage in the main plot, while residue retention, cropping systems, and fertilizer application were the sub‐plots, sub‐sub‐plots, and sub‐sub‐sub‐plots, respectively. There were nine treatments and four replications. Soil moisture, penetration resistance, and maize grain yield were measured between 2023 and 2024. Residue retention resulted in significantly ( p < 0.001) higher soil moisture (52.93–55.09 mm) in the 0‐ to 90‐cm soil depth than residue removal (25.98–28.91 mm). Maize–soybean rotation also had significantly higher ( p < 0.001) soil moisture in the 0‐ to 90‐cm soil depth (41.42–45.08 mm) than the continuous maize (36.29–41.07 mm). The penetration resistance in the wet period ranged between 90 and 320 pounds per square inch (PSI), and between 200 and 492 PSI during the dry period. Ripping resulted in 12% higher maize grain yields than hand digging. Maize–soybean rotation had a higher ( p < 0.001) maize grain yield (3.93 t/ha) than continuous maize system (1.57 t/ha). Nitrogen application at 90 kg N/ha in a continuous maize and 60 kg N/ha in maize–soybean rotation systems resulted in 118% and 85% higher maize grain yield, respectively, than when no nitrogen was applied. Similarly, applying phosphorous (60 kg P/ha) and potassium (60 kg K/ha) in maize–soybean rotation increased maize grain yield by 40% more than when potassium (60 kg K/ha) was applied as the only nutrient. Therefore, residue retention and ripping significantly improve soil health by enhancing moisture retention and reducing penetration resistance. Farmers in the sub‐humid western Kenya region can increase maize yields by adopting maize–soybean rotation, applying appropriate fertilizers (nitrogen, phosphorous, and potassium, each nutrient applied at the rate of 60 kg/ha), and implementing residue retention and ripping, especially under low rainfall conditions.