Effects of Organic Matter Amendment on Aggregate Stability of Some Agricultural Soils in Semi Arid Region of Nigeria

Soil aggregate stability is important in understanding the structural behaviour of soils. Soil aggregate stability is therefore an important index of soil productivity. The effect of chicken dung on aggregate stability of three (3) agricultural soils of Borno state namely sandy loam, sandy clay and clay soils was investigated in a laboratory experiment using a rainfall simulator. Chicken dung was added to these soils at 2% (w/w) and the aggregate sizes of 2-4 mm and 6-8 mm were prepared by sieving. These aggregate sizes were weighed and subjected to simulated rainfall for rainfall durations of 1, 2, 3, 4, 5, 10, 15, 20, 25 and 30 minutes using a rainfall simulator at an intensity of 226.6 mm/hr. The aggregate stability of the three (3) soils were calculated using the wet sieving method. The result revealed that 2% chicken dung incorporation did not influence stability of sandy loam soils, but improved the stability of the structure of both sizes of sandy clay and clay soils relative to the "controls”. The degree of stability however, varied with few soil types and aggregate sizes. Aggregate size of 2-4 mm showed poor resistance to rain drop forces as the rainfall depth increases compared to the aggregate size of 6-8 mm, but both performed better than the control. This implies that smaller sized aggregates are more vulnerable to detachment and transport irrespective of soil type. Clay soil aggregates were more stable than sandy clay soil irrespective of aggregate sizes. The use of chicken dung is hereby recommended to stabilise soil against erosion hazards.