An investigation of spatial variation in soil erosion, soil properties, and crop production within an agricultural field in Devon, United Kingdom

Abstract

This paper explores the role of tillage erosion and water erosion in the development of within-field spatial variation in soil properties and their contribution to variation in crop production. Data sources include spatial distributions of: plow soil concentrations of total N, total C, total and inorganic P; soil texture; grain yield and aboveground biomass; topographic attributes, derived from a detailed digital terrain model (DTM); net soil redistribution, derived from 137Cs measurements; tillage erosion, derived from simulation; and rill erosion, mapped in the field and simulated. Soil properties were found to be non-normally distributed and systematically related to slope curvature. Tillage erosion was found to be the dominant soil redistribution process on the basis of the close correlation between its distribution and that of the pattern of net soil redistribution. Tillage erosion also correlated closely with the soil properties, suggesting that soil redistribution by tillage is a major contributor to the spatial variation in soil properties. Relationships between crop production and soil properties and erosion rates were complex. Eroded and nutrient-depleted locations exhibited low rates of crop production, but low production was also found in some areas of high aggradation. Simulation of a further 40 years of tillage erosion suggests that spatial variation in soil properties will become more extreme and is likely to have a deleterious impact on crop production.