施肥对黑土农田土壤全碳、微生物量碳及土壤酶活性的影响

通过对吉林省德惠市中层黑土农田6年定位施肥试验研究表明,施有机肥、秸秆还田+有机肥、秸秆还田+化肥和半量有机肥+化肥处理较单施化肥、未施肥和休闲裸地处理提高了土壤全碳、全氮含量,降低了土壤碳氮比。对玉米播前、抽穗期和收获期土壤微生物量碳测定表明,抽穗期土壤微生物量碳最高,处理间差异显著,且不同采样时期的土壤微生物量碳与土壤全碳含量之间呈高度正相关。对土壤酶活性研究表明,施有机肥较单施化肥、未施肥和休闲裸地处理显著地提高了土壤脲酶、转化酶和过氧化氢酶活性;单施化肥处理对土壤转化酶和过氧化氢酶具有一定的抑制作用;而有机肥、秸秆和化肥之间的配合施用处理的土壤酶活性表现不一致。相关分析显示土壤微生物量碳与土壤酶活性呈显著或极显著正相关。该研究结果表明,长期向中层黑土农田增施有机物,不仅提高了土壤全碳和土壤微生物量碳的含量,而且也提高土壤酶活性,有利于提高土壤养分转化效率,可使黑土质量向健康方向发展。

Effect of Fertilization on Total Soil C, Microbial Biomass C and Soil Enzyme Activities in Farmland Black Soil

Based on the 6 years located fertilization experiments in a black soil farmland in Dehui,Jilin Province,this research showed that the treatments of farm yard manure,straw farm yard manure,straw chemical fertilizer and half dosage of farm yard manure chemical fertilizer increased total soil C and N content,but decreased soil C/N ratio compared with the treatments of chemical fertilizer,no-fertilizer and bare fallow.We also found that soil microbial biomass C was significantly different among the treatments at pre-sowing,corn tassel and harvest stages and the highest values were detected at tassel stage.Correlation analysis suggested that a positive relationship between total soil C and soil microbial biomass C was discovered at different sampling times.The study on soil enzyme activities showed that urease,catalase and invertase were enhanced in the treatment of farm yard manure compared with the treatments of chemical fertilizer,no-fertilizer and bare fallow;while catalase and invertase were inhibited in treatment of chemical fertilizer compared with no-fertilizer and bare fallow treatments.However,the combination of farm yard manure,straw and chemical fertilizer had different effects on different soil enzymes.Further analysis indicated that soil enzyme activities had positive relationship with soil microbial biomass C at P<0.05,P<0.01 and P<0.001 levels.From this research,we concluded that long-term application of organic manure to our black farmland soil not only increased total soil C and microbial biomass C contents,but also increased the activities of soil enzymes,which can in turn enhance the turnover efficiency of soil nutrition and improve soil quality.