Microbial Characters In No-tillage Soil With Paddy-upland Rotation

No-tillage was a saving time and labour,preserving water and soil and saving energy source,which played an import rool in modern agriculture yield.The survey site based on heizhu town of mingshan county,whose no-tillage was representative in hill and smooth area of sichuan province.The changes of the numbers of soil microorganism,microbial biomass and quotient in different soil layers and with different no-tillage years under the paddy-upland rotation were investigated.The microorganism activity in plough layer was evaluated by principal component analysis.The main results were as the belowing:1.The changes of the number of microorganisms in no-tillage soil were not identical after upland cropping and paddy cropping.The changes of the amount of bacteria fungi and actinomycetes in plough soil between no-tillage and conventional tillage soil were different after upland cropping,.The amount of bacteria in piough soil of no-tillage was lower 9.08%～66.37%than that of conventional tillage soil,while the amount of fungi and actinomycetes were 3.06～5.09 times and higher 42.65%～151.80%than that of conventional tillage,respectively,the amount of bacteria and fungi reached the lowest amount in no-tillage 5～6 and 7～8years,respectively,along with the increasing of no-tillage years,whereas the amount of actinomycetes was identical after no-tillage 5～6 years.After paddy cropping,the amount of bacteria,fungi and actinomycetes were lower 7.57%～42.25%,27%～70%and 27%～61.11%,respectively,than conventional tillage.The amount of fungi and actinomycetes were lowest in no-tillage 5～6 and 7～8years, respectively,among different no-tillage years,which of bacteria exists no significantly differences.2.The microbial biomass C and N in plough soil layer of no-tillage,which had highly remarkable relationships,were significantly higher than that of conventional tillage,but the microbial biomass P was significantly lower than that of conventional tillage after upland and paddy cropping.After upland cropping,the content of microbial biomass C and N in no-tillage soil were hgher 36.37%～86.35%and 13%～69.74%,respectively,than that in conventional soil.The microbial biomass C and N were lowest in no-tillage 10 and 7～8 years,respectively,and then decreased along with the the no-tillage years increasing.After paddy cropping,the microbial biomass C and N in no-tillage soils were higher 7.58%～77.10%,88%～29.54%,respectively,than that in conventional tillage soils.The microbial biomass C and N were highest in no-tillage 5～6 years,whose contents were increasing firstly,then decreasing,along with the no-tillage years increasing.The content of microbial biomass P in no-tillage soils was lower 33.87%～45.62%after upland cropping and 54%～22.72%after paddy cropping,respectively,than that in conventional tillage soils. there were no significantly differences among different no-tillage years.3.The changes of microbial quotient in plough soil layer of no-tillage ranged between 2.64%～3.99%and.13%～1.64%,respectively,after upland and paddy cropping.After upland cropping,the microbial queotient were significantly higher in mo-tillage 2～3, 5～6,and 7～8 years soils than that in conventional tillage soils.The microbial quotient increased firstly,then decreased,along with the no-tillage years increasing,which was lowest in no-tillage 10 years.After paddy cropping,the microbial quotient in no-tillage 7～8 years was lowest and there were significantly differences between conventional tillage and else no-tillage years soils,and there were no significantly differences between conventional tillage and no-tillage 2～3,5～6 and 10 years.4.The changes of the number of microorganisms,the content of microbial biomass and microbial quotient in no-tillage soil were identical after upland cropping and paddy cropping.The amount of bacteria and actinomycetes,the content of microbial biomass C, N,P and microbial quotient of 0～5cm layer soil were significantly higher than that of 5～10cm in no-tillage soil,which in conventional tillage soil existed no significantly differences.5.The principal component analysis indicated that the micobial activity in no-tillage soils was higher than that in conventional tillage,which was lowest in no-tillage 7～8 years,and increased in no-tillage 10 years.After paddy cropping,the microbial activity in no-tillage soils was lower than that in conventional tillage.With the no-tillage years increasing,the microbial activity was decreasing firstly then increasing.The microbial activity was lowest in no-tillage 5～6 years,then increasing in no-tillage 7～8 years.