Effects of no-tillage with coverage on carbon and nitrogen contents and nitrogen-mineralizing bacteria in soils cultivated with winter potato.

The experiment was conducted to study the effects of no-tillage with coverage on carbon and nitrogen contents and nitrogen-mineralizing bacteria in soils cultivated with winter potato.The soils were treated with(1) traditional cultivation(CK);(2) no-tillage with rice straw-covering(8 cm);(3) no-tillage with rice straw(8 cm) and black film-covering.The results showed that the carbon and nitrogen contents and nitrogen-mineralizing bacteria in 0-10 cm depth of soil were significantly higher compared to those in 10-20 cm depth of soil in each treatment.The contents of total organic carbon,active organic carbon,total nitrogen and alkaline nitrogen and the amount of ammonifying-bacteria and nitrobacteria in 0-10 cm depth of soil,in treatments 2 and 3,were significantly higher compared to traditional cultivation treatment.The differences of contents of total organic carbon,active organic carbon and total nitrogen and amount of ammonifying-bacteria between the coverage treatments and CK were significant or highly significant in 0-10 depth of soil.However,no significant differences of the above indicators in 10-20 depth of soil were observed between coverage treatments and CK.The results revealed that the regulation of no-tillage with coverage might increase the contents of carbon and nitrogen and amount of nitrogen-mineralizing bacteria in surface soil,and is helpful for decomposition and mineralization of organic nitrogen in soils to provide sufficient available nitrogen for proper growth of the crop.Therefore,it was an effective cultivation techniques and suitable for extension and application in production.