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在35℃下培养154天,用7、7、14、28、28、28、42天的培养间隔,测定了黄土、褐土和潮土16个土壤的氮素净矿化作用。培养前和每次间隔培养,土壤中的矿质氮用0.01 M CaCl_2淋洗收集,应用紫外分光光度计测定每次淋洗液中的NO_3-N。积累的净矿质氮与时间平方根t~(1、2)呈线性相关。采用G. Stanford和S. J. Smith以及J. Richter的数学模型计算了每个土壤的氮素矿化潜力N_6。结果表明,氮素矿化潜力能反映土壤的供氮能力,土壤氮素矿化潜力N_0占土壤全氮百分数为10.8—23.4%。矿化速率常数k的最可靠估算为0.0064±0.0006日~(-1)。
Nitrogen mineralization of 16 soil samples from loess, cinnamon soil and alluvial soil was determined by incubation at 35 ℃ for 154 days at 7, 7, 14, 28, 28, 28 and 42 days. The mineral nitrogen in the soil was collected by rinsing with 0.01 M CaCl 2 and the NO 3-N in each eluent was measured by UV spectrophotometer before and at intervals. The accumulated net mineral nitrogen is linearly related to the square root of time t ~ (1,2). The nitrogen mineralization potential N_6 of each soil was calculated using the mathematical models of G. Stanford and S. J. Smith and J. Richter. The results showed that the potential of nitrogen mineralization could reflect the nitrogen availability of soil, and the N_0 of soil N mineralization accounted for 10.8-23.4% of the total soil N content. The most reliable estimate of the mineralization rate constant, k, is 0.0064 ± 0.0006 days -1.