Soil Nitrogen and Environmental Chemistry Laboratory, Beltsville Agricultural Research Center-West, Beltsville, Maryland 20705; Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia 26506; and Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48823.
Appl Environ Microbiol. 1985 May;49(5):1053-6. doi: 10.1128/aem.49.5.1053-1056.1985.
Natural denitrification rates and activities of denitrifying enzymes were measured in an agricultural soil which had a 20-year past history of low pH (pH ca. 4) due to fertilization with acid-generating ammonium salts. The soil adjacent to this site had been limed and had a pH of ca. 6.0. Natural denitrification rates of these areas were of similar magnitude: 158 ng of N g of soil day for the acid soil and 390 ng of N g of soil day at the neutral site. Estimates of in situ denitrifying enzyme activity were higher in the neutral soil, but substantial enzyme activity was also detected in the acid soil. Rates of nitrous oxide reduction were very low, even when NO(3) and NO(2) were undetectable, and were ca. 400 times lower than the rates of N(2)O production from NO(3). Denitrification rates measured in slurries of the acid and neutral soil showed distinctly different pH optima (pH 3.9 and pH 6.3) which were near the pH values of the two soils. This suggests that an acid-tolerant denitrifying population had been selected during the 20-year period of low pH.
在一个农业土壤中测量了自然反硝化速率和反硝化酶的活性，该土壤由于使用了产生酸的铵盐而在过去 20 年中具有低 pH 值（约 pH4）的历史。该地点附近的土壤已被石灰化，pH 值约为 6.0。这些区域的自然反硝化速率相似：酸性土壤为 158ngN/g 土壤·天，中性土壤为 390ngN/g 土壤·天。中性土壤中估计的原位反硝化酶活性较高，但在酸性土壤中也检测到了大量的酶活性。即使 NO3-和 NO2-无法检测到，氧化亚氮的还原速率也非常低，约为从 NO3-产生 N2O 速率的 400 倍。在酸性和中性土壤的泥浆中测量的反硝化速率表现出明显不同的 pH 最佳值（pH3.9 和 pH6.3），这接近两种土壤的 pH 值。这表明在过去 20 年的低 pH 值期间，已经选择了耐酸的反硝化种群。
