Department of Biology, Utah State University, Logan, UT 84322-4820, USA.
FEMS Microbiol Ecol. 2010 Nov;74(2):316-22. doi: 10.1111/j.1574-6941.2010.00960.x.
An agricultural soil was treated with dairy-waste compost, ammonium-sulfate fertilizer or no added nitrogen (control) and planted to silage corn for 6 years. The kinetics of nitrification were determined in laboratory-shaken slurry assays with a range of substrate concentrations (0-20 mM NH(4)(+)) over a 24-h period for soils from the three treatments. Determined concentrations of substrate and product were fit to Michaelis-Menten and Haldane models. For all the treatments, the Haldane model was a better fit, suggesting that significant nitrification inhibition may occur in soils under high ammonium conditions similar to those found immediately after fertilization or waste applications. The maximum rate of nitrification (V(max)) was significantly higher for the fertilized and compost-treated soils (1.74 and 1.50 mmol N kg(-1) soil day(-1)) vs. control soil (0.98 mmol kg(-1) soil day(-1)). The K(m) and K(i) values were not significantly different, with average values of 0.02 and 27 mM NH(4)(+), respectively. Our results suggest that both N sources increased nitrifier community size, but did not shift the nitrifier community structure in ways that influenced enzyme affinity or sensitivity to ammonium. The K(m) values are comparable to those determined directly in other soils, but are substantially lower than those from most pure cultures of ammonia-oxidizing bacteria.
一种农业土壤分别用奶制品废料堆肥、硫酸铵肥料或未添加氮（对照）处理，并种植青贮玉米 6 年。在实验室摇床试验中，用一系列基质浓度（0-20 mM NH 4 (+)）在 24 小时内对来自三种处理的土壤进行硝化动力学测定。确定的基质和产物浓度符合米氏-门坦模型和 Haldane 模型。对于所有处理，Haldane 模型更适合，表明在类似于施肥或废物应用后立即发现的高铵条件下，土壤中的硝化可能受到显著抑制。施肥和堆肥处理的土壤硝化的最大速率（V（max））明显高于对照土壤（1.74 和 1.50 mmol N kg（-1）土壤天（-1））。K m 和 K i 值没有显著差异，平均分别为 0.02 和 27 mM NH 4 (+)。我们的结果表明，这两种氮源都增加了硝化菌群落的大小，但没有改变硝化菌群落结构，从而影响酶亲和力或对铵的敏感性。K m 值与在其他土壤中直接测定的值相当，但大大低于大多数氨氧化细菌的纯培养物的值。
