The pre-sidedress soil nitrate test (PSNT) is recommended in many states as a best management practice (BMP) for corn (Zea mays L.). A 2-yr study was conducted in Connecticut on a Woodbridge fine sandy loam soil (coarse loamy, mixed, mesic Aquic Dystrochrept) to determine NO3-N concentrations and losses in soil water from corn managed with three different N fertilization regimes: (i) PRE, 196 kg N ha−1 applied preplant; (ii) PSNT-1, 90 kg N ha−1 applied at preplant and any remaining N needs estimated by the PSNT (0 kg ha−1 in 1995 and 45 kg ha−1 in 1996); and (iii) PSNT-2, no preplant N and all N needs estimated by the PSNT (34 kg ha−1 in 1995 and 123 kg ha−1 in 1996). Percolate was collected with zero-tension pan lysimeters. Flow-weighted NO3-N concentrations from the PRE treatment were 22.3 mg L−1 in 1995 and 17.4 mg L−1 in 1996; the PSNT treatments were <8.0 mg L−1. Losses of NO3-N as a percent of N applied in 1995 were 20%, 10%, and 12% for PRE, PSNT-1, and PSNT-2, respectively, and 31%, 21%, and 21%, respectively, in 1996. Greatest leaching losses occurred after corn harvest. Corn yields were not significantly (P > 0.05) different among N treatments. These findings suggest that a well calibrated soil N test can reduce excess fertilization and the potential for NO3 contamination of ground water.
The pre-sidedress soil nitrate test and nitrate leaching from corn.Journal of Environmental Quality
PublisherCrop Science Society of America, Soil Science Society of America, American Society of Agronomy
Citation InformationGuillard, Karl, Thomas F. Morris, and Kelly L. Kopp. 1999. The pre-sidedress soil nitrate test and nitrate leaching from corn. Journal of Environmental Quality. 28:1845-1852.