Nutrient Use Efficiency in Maize (Zea mays): Response to Organic-Inorganic Phosphorus Substitutions in Western Kenya

Abstract

Aims: The degrading soil fertility and inefficient application of fertilizers limit the production of sustainable maize in sub-Saharan Africa. The objective of the study was to determine the effects of substituting organic and inorganic phosphorus sources (P) on nutrient uptake and the effectiveness of their use in maize production in western Kenya under varying Agro-ecological conditions. Study Design: The experimental layout was a randomized complete block design with 14 treatments involving the substitution of triple super phosphate (TSP) fertilizer by pressmud (PM) and cattle manure (CM) at 0%, 25%, 50%, 75% and 100% of the 30 kg P ha-1 rate, replicated three times. Place and Duration of Study: Field experiments were conducted at Kibos and Bumula in western Kenya, during the long rain season of 2021. Methodology: Soils were sampled to determine pH, C, N, P, and K contents. Composted pressmud and cattle manure was also analysed to establish nutrient. Agronomic data, including plant growth, grain and stover yield, were recorded and data analyzed using ANOVA. Results: Findings showed that the 50% substitution of TSP by both PM and CM, i.e., TSP15 + PM15 and TSP15 + CM15, was superior in terms of nitrogen and phosphorus uptake, agronomic efficiency indices (AEN, REN, AEP, REP), and grain yield compared to either organic or inorganic application alone. Conclusion: The gains in efficiency were site-specific, which depended on soil fertility and climatic variation. Results highlight the potential benefits of using Integrated Soil Fertility Management (ISFM) to improve nutrient use efficiency, minimize input inefficiencies, and enhance climate-resilient maize systems. The research paper gives new evidence on the P source integration approaches to sustainable intensification.