Evaluation of various nitrogen sources and rates on nitrogen movement, pensacola bahiagrass production, and water quality

Abstract

Movement of N through the soil profile under various N sources and rates was investigated in order to provide information that can be used to protect groundwater quality in Florida. The objective of this greenhouse experiment was to determine the distribution and leaching potential of various rates (0, 84 and 168 kg N ha⁻¹) and sources ((NH₄)₂SO₄ and NH₄NO₃) of N applied to Pensacola bahiagrass (Paspalum notatum Flugge). Bahiagrass sod was planted in PVC soil columns which were packed using each horizon (Ap, A22, Bh) of a virgin Myakka fine sand soil (sandy, siliceous, hyperthermic Aeric Haplaquods). Water was added to the soil columns once every 4 d and the effluent was collected from each soil column twice a week for a period of 3 months. Water and soil samples from each horizon (collected at the end of the experiment) were analyzed for NO₃‐N, NH₄‐N, pH, and electrical conductivity. Yield and tissue N were determined on grass samples harvested every 30 d. There was no significant differences in yield between N sources, however, there were trends showing yields to be higher with (NH₄)₂SO₄ as compared to NH₄NO₃. Nitrogen recovery was highest at the 84 kg N ha⁻¹ rate and was greatest with (NH₄)₂SO₄. Water NO₃‐N concentrations were below the U.S. E.P.A. 10 mg L⁻¹ water quality standard and averaged 0 ‐ 0.2 mg NO₃‐NL⁻¹.

Notes

Contribution from the Univ. of Florida Inst. Food and Agric. Sci., Florida Agric. Exp. Sta. Journal Series No. R‐01858.