Effects Of Tillage Measures On Soybean Field Soil Biological Activities

Soil is the foundation of agricultural production, physical and chemical change occurred in soil frequently, most of transformations of soil nutritions are achieved by soil microorganism and soil enzymes. Microbes in the natural soil could forecast the changes of soil environment sensitively, so soil biological activities are regarded as a sensitive index to measure soil quality. Study on the soil microbes and biological activities under different tillage measures could reveal the law of soil matter metabolism, furthermore offer important theoretical reference value for soil ecological environment.This research was conducted in experiment and practical base of Northeast Agricultural University from 2007, and 5 tillage treatments, conventional tillage, no tillage, no tillage with straw cover, minimum tillage and minimum tillage with straw cover were set. Conventional tillage was set as control. Cultivars Suinong 14 was used as material,and soil was sampled before seedling, after harvest and according to growth periods of soybean respectively, soil biological activities and soil nutritions in 2010 were examined by the analysis and determination in 0~20cm soil layer in 2010. The results showed that:Compared with CT, the NT, NTS and MTS treatments could significantly improve the soil urease, acid phosphatase, neutral phosphatase and invertase activity, but had little effect on alkaline phosphatase activity.Conservation tillage could increase the ability of keeping and supplying nitrogen and phosphate in soil. Compared with CT, the NT, NTS, MT and MTS treatments could significantly improve the soil microbial biomass N and P content.Compared with CT, the NT, NTS and MTS treatments could significantly improve the soil total nitrogen, toal phosphorus content, but had little effect on soil organic matter content. Soil enzymes and soil microorganism had a close relationship with the soybean growth. From initial blooming to seed filling stages, soil urease, acid phosphatase, neutral phosphatase , invertase activities, soil microbial biomass N, P content, soil total nitrogen, toal phosphorus and organic matter content under NT, NTS and MTS was obvious. Most was concentrated in 0~10cm layer.There was a significant (p<0.05) or very significant (p<0.01) positive correlation among soil urease, phosphate and invertase activities. Soil urease and invertase activities had a significant (p<0.05) or very significant (p<0.01)positive correlation with soil total nitrogen, toal phosphorus and soil organic matter content. To Characterize the soil fertility was more effective. There was a significant (p<0.05) or very significant (p<0.01) positive correlation among soil microbial biomass N, P content and soil urease, phosphate and invertase activities. And very significant (p<0.01) positive correlation with soil total nitrogen, toal phosphorus and soil organic matter content.