| Although the percentage of surface irrigated land in the United States is declining, it is still used on 43% of the irrigated land, and 51% of the surface irrigated land is irrigated down furrows or rows (USDA, 2004). Water flowing in irrigation furrows often detaches and transports soil, reducing crop productivity and impairing off-site water quality. Crop yields were at least 25% less on fields eroded from over 80 years of furrow irrigation in south-central Idaho (Carter et al., 1985). Measured soil loss from furrow irrigated fields in this area varied from 1 to 141 Mg ha-1 annually (Berg and Carter, 1980) while the annual average soil loss from the entire irrigated tract was 0.46 Mg ha-1 in 1971 (Brown et al, 1974). This soil, and associated... |
