Losses of Nitrogen and Mineral Nutrients from Corn Grown in Greenhouse Pot Experiments
1974
Terman, G. L. | Allen, S. E.
Three greenhouse pot experiments were conducted: the first to compare rates of N as ammonium nitrate (AN) and S-coated urea products (SCU, 6 and 12% initial dissolution in water) for corn (Zea mays L.); the second to measure dissolution of SCU-5, SCU-12, and SCU-20 in uncropped soil; and the third to compare rates of N, P, and K for corn. Accumulation by and subsequent losses of nutrients from corn tops and roots at three harvest dates were measured. Significant losses of N, P, and K from corn tops or tops + roots fertilized with high rates of N as AN and SCU-12 or of P and K occurred during growth from 6 to 8 or 9 weeks. These losses were closely associated with reduction in growth rates resulting from depletion of N, P, or K under test. No appreciable nutrient losses occurred from slower growing plants fertilized with SCU-6. Three SCU products released N in uncropped cultures over a 9-week period. Leaching of nutrients from corn top growth by guttation, dew, or rain was not a factor in these experiments. Consequently, most of the losses were through the roots. Competition by growth of microorganisms stimulated by root exudates is a probable explanation.
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