In a series of laboratory incubation studies, we evaluated the effects of temperature, moisture, and nitrogen amendment on nitrogen mineralization rates in the acidic Lakehurst and Atsion sands of the New Jersey Pinelands. The average potentially mineralizable nitrogen (No) values for the Lakehurst and Atsion sands were 87 and 94 μg/g (170 and 630 kg N/ha), respectively. Mineralization constants (k) were 0.0501 and 0.0756/wk at 25 and 35°C, respectively, for the Lakehurst sand and 0.0327 and 0.0452/wk for the Atsion sand. Maximum mineralization occurred at 35°C for both soils with Q10 values ranging from 1.8 to 2.1. Optimal soil moisture tensions for nitrogen mineralization were between −0.01 and −0.03 MPa. A soil moisture tension of −0.1 MPa reduced nitrogen mineralization with the Lakehurst sand, but not with the Atsion sand. Amendment of the soil with ammonium sulfate increased mineralization with the Atsion sand, but had no effect on the Lakehurst soil. Conversely, ammonium chloride amendment increased the nitrogen mineralization rates in the Lakehurst, but not the Atsion sand. Urea amendment inhibited nitrogen mineralization with both soils. No nitrate accumulation was observed in any of the nitrogen-amended samples.
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