A conservation practise or combination of practises designed to maintain agricultural productivity while reducing point- and nonpoint- source water pollution. State water quality agencies (or their designees) determine BMPs to fit local conditions and to make the most efficient use of natural resources and purchased inputs. The term has been defined as generally recognised farmer management practises designed to reduce or prevent contamination of ground water and surface water, erosion, and runoff from cropland, including the use of conservation tillage, no-till, ridge plating, strip tillage, contour farming, strip cropping, irrigation water management, judicious fertiliser application, slow-release fertilizers, soil and tissue testing, and vegetative buffer strips.