%0 Journal Article
%T The Effect of Rainfall Characteristics and Tillage on Sheet Erosion and Maize Grain Yield in Semiarid Conditions and Granitic Sandy Soils of Zimbabwe
%A Adelaide Munodawafa
%J Applied and Environmental Soil Science
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/243815
%X In semiarid regions, rainfall is one of the primary factors affecting soil erosion and crop production under rain-fed agriculture. The study sought to quantify the effect of rainfall characteristics on sheet erosion and maize grain yield under different tillage systems. It was carried out under semiarid conditions and infertile sandy soils of Zimbabwe. Rainfall amount and intensity were recorded every 24 hours, while sheet erosion was measured from four tillage systems (Conventional Tillage (CT), Mulch Ripping (MR), Tied Ridging (TR) and Bare Fallow (BF)). Maize (Zea mays L.) was grown on three tillage systems (CT, MR, and TR). Rainfall amount varied significantly ( ) between seasons (164¨C994£¿mm). CT recorded the highest average soil losses (15£¿t/ha), while MR and TR recorded 1.3 and 1.2£¿t/ha, respectively. Maize grain yields increased with increasing seasonal rainfall giving yield-responses of 0.9£¿t/ha (TR) to 1.3£¿t/ha (MR) for every 100£¿mm rainfall increment. Overall, treatments didnot differ significantly ( ), except during drier seasons ( ). Regression equations showed that yields can be confidently predicted using rainfall amount and time, with values of 0.82 to 0.94. Maize grain yields proved to be mostly dependent on rainfall amount than fertility. The productivity of the soils decreased with increased length of cultivation. 1. Introduction Rill and gully erosion in the smallholder areas of Zimbabwe is largely under control through mechanical conservation structures such as contour ridges, grassed waterways, and storm drains [1]. However, sheet erosion is still a major threat to soil fertility and productivity. The sheet erosion process is selective and deprives the soil of its fine particles (clay and organic matter) [2]. These particles are easily splashed out and carried in suspension, while the heavier particles remain behind [3¨C5]. The soils are thus impoverished as these nutrient reservoirs are lost together with inherent and applied plant nutrients. The bulk density of the soils is increased and plant available water is decreased. According to Stocking and Peake [6], the changes in soil conditions, in many cases, may be describing the effect of erosion induced low soil productivity. In soil erosion research, rainfall amount and intensity (erosive power of rainfall) have been found to be the fundamental factors affecting soil erosion [7, 8]. The impact of raindrops on the soil surface results in temporary capping of the soil and lowered infiltration rate, thus generating runoff [9¨C11]. Runoff is directly dependent on rainfall amount and
%U http://www.hindawi.com/journals/aess/2012/243815/