Crop Nitrate Availability and Nitrate Leaching under Micro-Irrigation for Different Fertigation Strategies

Abstract

A drip-industry recommendation is to fertigate during the middle one third or one half of the irrigation set. However, fertigation events occurring for short time periods are common, which practice could affect crop nitrate availability and nitrate leaching below the root zone. The pattern of fertilizers such as nitrate and urea around a drip line can depend of the duration of fertigation and the timing of the fertigation relative to the irrigation set time. Thus, a study was conducted to evaluate nitrate distributions in the soil for various fertigation strategies, soil types, and methods of microirrigation. Results showed that short fertigation events occurring near the beginning of an irrigation event can move much of the nitrate beyond the root zone and contribute to leaching. Short fertigation events at the end of the irrigation event leave much of the nitrate near the drip line. Fertigation events of longer duration distribute nitrate more uniformly throughout the root zone.