Effect of Leaf Mulch from Selected Agroforestry Tree Species on Soil Physico-Chemical Properties in South-West Nigeria

This study investigated the effects of leaf mulches from four agroforestry tree species-Leucaena leucocephala, Artocarpus altilis, Sesbania grandiflora, and Moringa oleifera on soil physico-chemical properties under field conditions in South-West Nigeria.A randomized complete block design was employed with three mulch application rates (1.5, 2.0, and 2.5 kg) and an untreated control.Findings demonstrated that mulch application significantly (p < 0.01) influenced soil pH, electrical conductivity, total nitrogen, organic carbon, phosphorus, and exchangeable cations, producing marked improvements compared with control and pretreatment conditions.L. leucocephala and S. grandiflora were most effective in enhancing soil pH, phosphorus availability, and cation exchange capacity, while M. oleifera and A. altilis contributed notably to organic carbon and micronutrient enrichment.Higher application rates (2.0-2.5 kg) generally yielded superior results, though species-specific interactions highlighted the stronger fertility-restoring potential of leguminous species.Post-treatment analyses showed substantial increases in key soil nutrients such as phosphorus (39.72 mg/kg vs. 13.66 mg/kg in control), calcium (1,807.61mg/kg vs. 877.75mg/kg), and effective cation exchange capacity (11.07 cmol/kg vs. 5.99 cmol/kg).These findings emphasise the role of agroforestry tree leaf mulches as a low-cost, ecologically sound strategy for improving soil fertility, enhancing nutrient cycling, and advancing sustainable agricultural productivity in humid tropical ecosystems.