Nitrogen Application Timing for Corn Production Under Sub-Surface Drip Irrigation.

Innovative and more efficient irrigation technologies can be used to sustain irrigated agriculture when water is limiting and to protect the environment. Development of SDI management practices for row crop production is needed to maximize economic returns and protect the environment. This study was conducted over a two-year period (2006 and 2007) to determine the optimum nitrogen application timings for corn production under SDI. Treatments included two N rates, 233 kg N ha-1 (recommended rate) and 186 kg ha-1 (recommended rate minus 20%) and three N application timing strategies representing different percentages of the total N applied at pre-plant, planting, and plant growth stages V10, V14, VT and R3 (treatment 1 = 5,30,29,23,13, and 0%; treatment 2 = 5,30,13,23,29 and 0%; treatment 3 = 5,30,29,23,0, and 13%). Treatments were arranged in a randomized block factorial design with four replications. In 2006, corn grain yield and total biomass were not different for all treatments. In 2007, there were no differences in grain yield between the N application timing treatments but the recommended N rate treatment had higher yields compared to the recommended rate minus 20% treatment. Total biomass in 2007 was not different between all treatments. Soil nitrate-N mass distribution will be considered after samples are analyzed. Application of 13% of the N at the R3 growth stage did not decrease yield. In this study, the timing of N application through an SDI system did not affect yield.