Soil erosion in south Somerset

Abstract

Summary Local soil erosion has long been a problem on very fine sandy and silty soils in south Somerset. Some 40 fields in arable use were chosen randomly and monitored monthly for erosion in the winter of 1982–3. Erosion was measured along fixed traverses and then compared with soil attributes, site factors and cultivation practices. Winter cereals were worst affected with a third of the fields having soil losses in excess of 4 m 3 /ha. There was least erosion on bare ploughed ground and moderate losses on cash root crops. Soil type, organic-carbon content, clay content, drill direction, wheeling density and slope all affected soil loss in winter cereal fields. Erosion did not assume serious proportions until a combination of soil surface conditions and soil wetness allowed run-off to form rills. Only moderate falls of rain were then needed for widespread removal of soil. Preventative measures include grassing slope convexities, more grass in the rotation to improve soil organic matter and structure, avoiding wheelings, drilling across the slope and keeping headland widths to a minimum.