Monitoring of water erosion on arable farms in England and Wales. 1990–94

. The incidence of soil water erosion was monitored in 12 erosion‐susceptible arable catchments ( c . 80 fields) in England and Wales between 1990 and 1994. Factors associated with the initiation of erosion were recorded, and the extent of rills and gullies measured. Approximately 80% of the erosion events were on land cropped to winter cereals. In 30% of cases, the initiation of erosion was linked to valley floor features, which concentrated runoff. Poor crop cover, wheelings and tramlines were also assessed as contributory factors in 22%, 19% and 14% of cases, respectively. In c . 95% of cases rainfall events causing erosion were ≥10 mm day −1 and c . 80% were >15 mm day −1 . Erosion was also associated with maximum rainfall intensities of >4 mm h −1 for c . 90% of cases and >10 mm h −1 for c . 20%. Mean net soil erosion rates were approximately 4 t ha −1 per annum (median value 0.41 t ha −1 per annum) and associated mean P losses 3.4 kg ha −1 .