Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: 9/11/2001
Publication Date: N/A
Technical Abstract: Controlling nutrient leaching presents a challenge for developing nutrient management plans that must develop rate and time of application strategies for specific soils, hydrology, and the crop- tillage systems. Nutrient leaching is usually applied to N movement out of the rootzone, but it can also occur for P. Major leaching events occur when soil nutrient concentrations are high and water is moving through the profile. Nutrient management factors such as rate and time of nutrient application, selection of crop rotation, and use of scavenger crops can be used to lower soil nutrient concentrations and reduce leaching risks. The quantity and time of irrigation/rain, soil water holding capacity and hydraulic conductivity, and the degree of preferential-flow vs. convective-flow will affect soil water movement. The primary management factor affecting water movement through sub-humid region soils is irrigation management. In humid regions climatic factors exert major influences on leaching by affecting the quantity and time of precipitation in relation to crop water use, the intensity of rain (run-off vs. infiltration), and the probability of surface-saturation conditions (preferential-flow events). A series of nutrient management alternatives will be presented for both rain-fed and irrigated systems that illustrate the application of the above principles to increase nutrient uptake efficiency and protect water quality.