Effect of organic fertilizer use on crop yield and soil health in maize production in Kenya

Sub-Saharan Africa faces an elevated risk of food insecurity. The agricultural sector in Sub-Saharan African countries encounters significant challenges in increasing crop production to meet the ever-growing food demand driven by population growth and economic development. Nutrient management is a critical component of crop production, yet nutrient input levels in the region are notably low. In many areas of cropland, nutrient balances are in deficit (Liu et al., 2010). At the recent Africa Fertilizer and Soil Health Summit, African leaders pledged to strengthen nutrient management practices to enhance food production through increased fertilizer use. Fertilizers can be categorized into different types. Most discussions on fertilizer policy to date have focused on inorganic fertilizers, which are produced through industrial processes. In contrast, organic fertilizers are derived from naturally occurring materials. The use of organic fertilizers may offer additional long-term benefits, particularly for improving soil health. Notably, soil organic carbon is a key indicator of soil health, and organic fertilizers, being rich in carbon, can contribute to increasing soil carbon content. A study was conducted to evaluate the impact of organic fertilizers on crop productivity and soil health, focusing on maize production in Kenya. Maize is the primary staple crop in Kenya, with a harvested area of 2.1 million hectares, representing about 40% of the total harvested area for all crops in the country (FAOSTAT). Maize is also the largest consumer of fertilizers in Kenya. It is estimated that maize cultivation uses 2.8 million tons of fertilizers annually, accounting for approximately 50% of the country's total fertilizer consumption. Fertilizers are applied on about 70% of the maize-planted area (IFDC & AFAP, 2018). However, the average maize yield in Kenya remains low, at less than 2 metric tons per hectare (FAOSTAT), indicating suboptimal management practices or inadequate input levels, including insufficient fertilizer use (De Groote, 2023).