The Study On The Effect Of Cultivation And Fertilizer To Nitrogen Cycling Bacteria On Black Soil

This article systematically studied the bacteria,five nitrogen cycling bacteria and relation between the nitrogen cycle bacteria and ntrogen transformation on the basis of Ji Lin black soil.It established the theory basis of understanding the mechanism of black soil degeneration.The study indicates rafter tillage, physical and chemical properties of black soil have changed a lot.The main expression is decreasing of nature fertility.But we can improve the soil physical property by equitable fertilizing.The physical property is improved and the content of chemical nutrition is obviously increasing by chemical-organic fertilizing.The physical property is not sure to be improved,but the content of chemical nutrition is increasing .Shows:the content of total N(2.32g/kg),organic N(2.30g/kg) and organic matter(2.93%) is the most in chemical-organic fertilizer soil,and next is non-farm soil,chemical fertilizer soil and non-fertilizer soil.The content of NH₄⁺ and NO₃^- is more in the fertilizer soil (NPK soil and NPK+M soil) than in the non-fertilizer soil(CK soil) and non-farm soil.The content of microbial biomass C/N (microbial biomass C 391.31mg/kg,microbial biomass 27.10mg/kg) is the most in non-farm soil,and next is chemical-organic fertilizer soil,chemical fertilizer soil and non-farm soil.After tillage,the quantity of the bacteria,ammonitation bacteria,nitrify bacteria,anti-nitrify bacteria and nitrogen-fixing bacteria are increasing.It can add the bacteria quantity by fertilizing chemical fertilizer;the quantity of ammonitation bacteria ,nitrify bacteria and nitrogen-fixing bacteria are increasing in fertilizing soil,and the quantity of ammonitation bacteria and nitrify bacteria are more in the chemical fertilizer soil than in the chemical-organic fertilizer soil.We can decrease the quantity of anti-nitrify bacteria by fertilizing.And the cross section variation of bacteria and nitrogen cycle bacteria shows the regular:the quantity is more in the upper layer(0-20cm) than in the lower layer(20-40cm).The distribution of nitrogen cycle bacteria in the different soils shows ammonitation bacteria > nitrogen-fixing bacteria > nitrify bacteria > anti-nitrify bacteria.After tillage,the content of total nitrogen and microbial biomass nitrogen is decreasing in non-fertilizer soil;the content of microbial biomass nitrogen is partly increasing in chemical fertilizer soil;the content of total nitrogen and microbial biomass nitrogen is increasing and the content of NH₄⁺ and NO₃^- is increasing in four tested soil.The quantity of ammonitation bacteria is increasing and the content of NH/ is decreasing;the quantity of nitrify bacteria is increasing and the content of NO3" is decreasing;the quantity of anti-nitrify bacteria is increasing and the content of NH4+ and NO3" is increasing;the quantity of nitrogen-fixing bacteria is increasing and the content of total nitrogen is increasing in the upper layer of non-fertilizer soil.Accepting the increasing of ammonitation bacteria and the decreasing of NHU+ content,the other nitrogen nutrition variation in the lower layer is opposite to the upper layer soil.After tillage and fertilizer(including chemical fertilizer and chemical-organic fertilizer) the quantity of nitrogen-fixing bacteria is increasing and the content of total nitrogen is increasing;the quantity of ammonitaion bacteria is increasing and the content of NH/ is decreasing;the quantity of nitrify bacteria is increasing and the content of NO3" is increasing;the quantity of anti-nitrify bacteria is increasing and the content of NH/ is decreasing, NO3" is increasing in the upper layer of chemical fertilizer soil.The quantity of the four nitrogen cycling bacteria is increasing and the content of nitrogen nutrition in the upper layer of chemical-organic soil is opposite to the content in the upper layer of chemical soil. The quantity of nitrify bacteria is increasing and the content of NO3" is increasing; the quantity of anti-nitrify bacteria is increasing and the content of NHU+ is decreasing, NO3* is increasing in the lower layer of fertilizer soil(including chemical fertilizer and chemical-organic fertilizer). The quantity of ammonitation bacteria is increasing and the content of NH4+ is increasing in the lower layer of chemical fertilizer and the quantity of ammonitation bacteria is increasing and the content of NH/ is decreasing in the lower layer of chemical-organic fertilizer soil.The analysis of relation between nitrogen cycle bacteria and environmental factors in soil shows: in four tested soil ,the main factor of environmental factors affecting five nitrogen cycle bacteria is different .The main factor affecting five nitrogen cycle bacteria is total N and organic matter in non-farm soil;the main factor affecting five nitrogen cycle bacteria is pH and available postassium in non-fertilizer;the main factor is affecting five nitrogen cycle bacteria is microbial biomass N in chemical fertilizer soil ; the main factor is affecting five nitrogen cycle bacteria is microbial biomass N and microbial biomass C in chemical-organic fertilizer soil.