Controls over net inorganic nitrogen transformations in an age sequence of Pinus elliottii plantations in north Florida
1989
DiStefano, J.F. | Gholz, H.L.
The controls over net ammonification and net nitrification in recently clearcut, 9-year-old and 29-year-old plantations of Pinus elliottii in north Florida were investigated using a combination of field (in situ) and laboratory soil incubations. Fertilization with PK and NPK and prescribed burning were also used in the field to further determine effects of P and NH+4-N availability on net N transformations. Results revealed complex relationships among N availability and plantation age, incubation method, season and treatment. Ammonification rates were generally lower than those found in other studies. The clearcut, 9-year-old and NPK-fertilized plots had the greatest rates. The single burns and PK-fertilization had little effect on rates, although soil chemistry was significantly altered. Net nitrification rates were negligible except on the NPK-fertilized which had greatly elevated rates of both net ammonification and net nitrification. We conclude that P availability had little apparent affect on net N transformations in the surface soil and that N availability was least in the oldest stand.
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