The effect of cultivation method on erosion in agricultural catchments: Integrating AHP in GIS environments

The cultivation method used in agricultural catchments can have a great effect on erosion processes; as such, determining the effects on form and degree is crucial. One commonly held hypothesis is that a shift to minimum tillage methods should reduce the rate of erosion. Here, we examine the effect of cultivation methods and environmental conditions on soil erosion risks in field crops and orchards in an agricultural catchment in northern Israel. The examination was conducted using AHP (analytic hierarchy process) and GIS (geographic information system)-based computer simulations. Field validation of the simulations was conducted during the 2009-2010 winter season. The spatially explicit data on cultivation method, combined with environmental and climatic data, yielded an explanation of most of the variation in erosion risks in the catchment (kappa =0·93). Of the 10 criteria examined, the cultivation method and slope were the two variables with the greatest effect on increased soil erosion. Furthermore, soil loss risks were reduced substantially as a result of substituting conventional tillage with reduced tillage; substituting reduced tillage with conservation tillage; and changing the tillage direction to perpendicular to the direction of the slope. These results are reasonable in light of the modifications that mechanical tools cause in the soil structure, as observed in the penetration depth and the aggregate stability measurements used in this study. Despite the difficulty in collecting spatially explicit data on cultivation methods, we believe that it is of utmost importance to use such data to study erosion risks in agricultural catchments.