Irrigation well water in Nebraska: essential nutrient contents and other properties

Water nutrient concentrations and other properties were surveyed by sampling water from 642 irrigation wells in Nebraska. The amount of Ca, Mg, S, Cl, and B applied in irrigation exceeds removal in 15 Mg ha-1 of corn (Zea mays L.) grain harvest for most wells. Irrigation supply exceeded corn grain harvest removal of K, Mn and Mo for >20% of the wells. The supply of P, Zn, Cu, Fe, and Mo was generally very low but sufficient with some wells to be considered in nutrient management plans. The median level of nitrate N was 4.4 ppm with 25% of the wells having >10 ppm NO3-N which is above the suitability limit for human consumption. The agricultural lime equivalent applied with one or two ML of irrigation was enough to neutralize the acidifying effect of 200 kg ha-1 of fertilizer-N for 70% or 89% of the wells. Nutrient and lime supply was relatively low for Sandhills wells and relatively high for wells in river valleys of <100 ft depth. No wells had excessive Na levels but 0.3% of t...