摘要
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。
For expounding the effect of nitrogen （N） application levels on soil microbiological characteristics, the indoor analytical method was adopted to compare the influences among five N application levels （No N application, 70% ）〈 optimum N application, optimum N application, 130% ;K optimum N application and habitual N application from the majority of farmers） on soil microbial biomass C, N and enzyme activities under three different fertility basics. The results showed that the plot with high fertility was conducive to its accu mulation of microbial biomass N （MBN）. With the amount of N fertilizer increasing, the microbial assimilation of N （MBN） was enhanced by all the tested plots. However, the increasing trend of MBN experienced a glide path in both experimental sites with moderate and low fertility when the amount of urea reached 312 kg/hm2. The discrepancies in soil fertilities had no regular impact on MBC. The influence rule of N application on MBC from the plot with low fertility was performed the first promotion and later inhibition, which was just the opposite at both moderate and high fertility plots. Both optimum and habitual N applications were helpful to enhance the activities of sucrase and urease, respectively. At the moderate or low fertility plots, the catalases were decreased first and then increased along with increasing amount of N application, but the change rule from the moderate site was diametrically opposite. Compared with no N application, the protease was inhibited slightly by 70 % X optimum N application, and then enhanced gradually with the rising amount of N application. When the amount of urea reached 312 kg/hm2 , the activity of protease attained the maximum. In the moderate N range （0--270 kg/hm2） , the alkaline phosphatase was improved by urea.
出处
《水土保持学报》
CSCD
北大核心
2014年第4期148-152,167,共6页
Journal of Soil and Water Conservation
基金
国家科技支撑计划项目(2013BAD07B02
2013BAC09B01)
农业部公益性行业(农业)科研专项(201103003)
吉林省教育厅"十二五"科学技术研究项目(吉教科合字2013第64号)
吉林省博士后基金项目(01912)
