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为阐明不同肥力区域,施氮水平对土壤微生物学特性的影响,采用室内分析法系统比较3个肥力条件下,5个施氮水平(不施氮、70%×优化施氮、优化施氮、130%×优化施氮和农民习惯性施氮)对土壤微生物生物量碳、氮以及酶活性的影响。结果表明:较高肥力有利于微生物生物量氮(MBN)的保蓄。随氮肥施用水平提高,微生物所同化的氮在各肥力区均有所增加,继续增大尿素用量(312kg/hm2),中、低肥力土壤MBN的数值有所回落;而肥力差异未对微生物生物量碳(MBC)产生规律性的影响。低肥力条件下,施氮对MBC的影响表现为先抑制后促进的作用,高、中肥力则与之相反;优化施氮与农民习惯性施氮均有助于蔗糖酶和脲酶活性的提高;在高、低肥力区域,随施氮水平增加,过氧化氢酶活性先降低而后升高,与在中等肥力区所表现的规律恰好相反。与无氮对照(N0)相比,70%优化施氮对土壤蛋白酶活性有抑制作用,而随氮肥用量增加,蛋白酶活性渐趋升高,尿素用量为312kg/hm2时的蛋白酶活性达最大值;适量施氮范围内(0~270kg/hm2),增施尿素有利于碱性磷酸酶活性的提升。
In order to elucidate the effects of different fertility and nitrogen application rates on soil microbiological characteristics, five nitrogen application rates (no nitrogen application, 70% × optimum nitrogen application, optimized nitrogen application rate, 130% × optimized nitrogen application and peasant habitat N application) on soil microbial biomass carbon, nitrogen and enzyme activity. The results showed that higher fertility was beneficial to the conservation of microbial biomass nitrogen (MBN). With the application of nitrogen fertilizer increased, the amount of nitrogen assimilated by microorganisms increased in all fertility zones and continued to increase the amount of urea (312 kg / hm2), and the values of MBN in middle- and low-fertility soils declined slightly. However, The effect of regularity on the amount of carbon (MBC) produced. Under low fertility conditions, the effects of nitrogen application on MBC were the first to inhibit and then the high and middle fertility were opposite. Optimizing nitrogen application and peasants habitat application of nitrogen all contributed to the increase of sucrase and urease activities. In high and low fertility areas, the catalase activity decreased firstly and then increased with the increase of nitrogen application rate, which was the opposite of the regularity in medium fertility area. Compared with nitrogen-free control (N0), 70% nitrogen application had an inhibitory effect on soil protease activity. With the increase of nitrogen application rate, the protease activity increased gradually. When the urea dosage was 312 kg / hm2, the protease activity reached the maximum. Appropriate amounts of nitrogen (0 ~ 270kg / hm2), increased urea is conducive to the improvement of alkaline phosphatase activity.