New integrated agronomic cropping systems that nearly eliminate irrigation-induced erosion,
significantly reduce nitrate leaching potential, increase crop utilization of nitrogen from legume
sources and fertilizer, improve irrigation uniformity, decrease production costs, and increase net
profits have resulted from several years of research at Kimberly, Idaho. These systems include
growing corn or cereal without tillage following alfalfa to efficiently utilize nitrogen from the
legume and reduce irrigation-induced erosion. Where no corn was grown following alfalfa,
nitrate-N accumulated up to 550 lbs/ac in the upper 5 feet of soil compared to only 50 lbs/ac
where corn was grown. Where beans were grown for two seasons following alfalfa, nitrate-N
leaching was 50 lbs/ac more than where corn and then winter wheat were grown. Banding
nitrogen fertilizer on the opposite side of the corn row from the irrigation furrow used all season
reduced nitrate leaching as compared to where a furrow was irrigated on the same side of the row
as the fertilizer band. Nitrate moves below the root zone during wet winters by deep drainage
and pass through flow. Polyacrylamide (PAM) concentrations of 10 ppm or less applied into the
irrigation water can almost eliminate furrow erosion, and it increases infiltration. Applying
cheese whey alone and in combination with straw at whey rates of 12 gallons and straw rates
of 4 lbs/100 ft of row before beginning irrigations reduced sediment loss by more than 95%
