Determination of Soil Aggregate Stability Under Different Organic Matter Inputs in Kebbi State, North West Nigeria

This study determines the aggregate stability of soils under different organic matter input treatments in Kebbi State, located in Nigeria's North West geopolitical zone. Soil aggregate stability is a key indicator of soil structural quality, determining resistance to erosion, water infiltration capacity, and root penetration, and is particularly sensitive to organic matter management in the fragile sandy loam soils of the semi-arid North West zone. A field experiment was conducted in Argungu local government area using a randomised complete block design with five organic matter treatments: no addition (control), crop residue retention at 4 tonnes per hectare, farmyard manure at 5 tonnes per hectare, green manure from Tithonia trundata biomass at 4 tonnes per hectare, and compost at 5 tonnes per hectare, applied for three consecutive seasons. Soil aggregate stability was measured by wet sieving at two Soil Scienceh intervals (0 to 10 and 10 to 20 cm) each season. Organic carbon, bulk density, and water-stable macroaggregate content were measured concurrently. Findings revealed that farmyard manure and compost treatments produced the greatest improvement in water-stable aggregate content, with mean macroaggregate proportion increasing from 38 percent in the control to 61 and 65 percent respectively after three seasons. Organic carbon was significantly correlated with aggregate stability (r = 0.84) across all treatments. Green manure treatment showed rapid but shorter-lived aggregate improvement due to faster decomposition. The study recommends compost application as the most durable strategy for improving aggregate stability in Kebbi State sandy loam soils. Keywords: aggregate stability, organic matter, compost, Kebbi State, soil structure.