Evaluation of Effects of Organic Soil Amendments on Runoff andSoil Erosion at Different Rainfall Intensities

Abstract

Soil erosion poses a serious threat to the sustainable use of soil for crop productionfor thecontinual survival of human race. Organic soil amendments are being used to stimulate microbial activity which enhance availability of nutrients in the soil to plants. Also, organic  amendmentsare used for soil conservation purposes, but there is need for comprehensive considerationoftheir comparative  effectiveness on controlling soil losses. The present study is, therefore, anattempt to prepare and determine the efficiency of soya beans  chaff, saw dust and debris (drygrasses) on runoff and soil erosion control. The experimental soils were collected from18cmdepth below  the top soil and were treated with the following soil amendments namely: soyabeans chaff, saw dust and debris for conservation  measures. The runoff and soil loss weresimulated under artificial rainfall intensities of 45, 65, 85 and 105 mm/h using an outdoor rainfall simulator. The results showed that all the amendments applied were able to reduced soil loss andrunoff volume compared to the control  (soil without amendment) and the effect is more onsoil treated with dry grasses. Therefore, the debris reduced the soil loss at a rate of  75.07%comparedto the control plots, while Soya beans chaff and saw dust had 30.24% and 46.45%reductionratesrespectively. The  maximum reduction in soil loss for all soil amendments was obtained at therainfall intensity of 45 mm h−1 with the rates of 86.94, 62.84  and 38.77 %reduction for debris, saw dust and soya bean chaff, respectively. The results showed that debris amendment was most  effective in runoff and soil erosion control compared to others.