Effects Of Long-term Fertilization On Soil Microbiological Characteristics Of Three Parent Materials

Part substitution of organic fertilizer for chemical fertilizer is an effective measure to ensure food security and comprehensive utilization of resources in China.This paper is based on the soil ripening experiment of three parent materials,purple sand shale,granite and quaternary laterite,which started in1982.There are six kinds of experimental treatments: No fertilizer(CKT),straw returned(CKR),organic fertilizer(OMT),organic fertilizer with straw returned(OMR),fertilization of chemical fertilizer(NPKT),fertilizer with straw returned(NPKR),microplate fluorescence method,chloroform fumigation,hydrochloric acid hydrolysis-gas chromatography and RDA analysis,etc.Soil microbial biomass carbon(MBC),microbial biomass nitrogen(MBN)and C,N,P cycle enzymes:?-1,4-glucosidase(?G),?-1,4-glucosidase(?G),?-1,4-xylosidase(?X),Cellobiohydrolase(CBH),L-leucine aminopeptidase(LAP),?-1,4-N-acetylglucosaminosidase(NAG),Acid phosphatase(AP),Polyphenol oxidase(PPO)?Catalase(CAT)and glucosamine(Glc N),galactosamine(Gal N),muramic acid(Mur A),total amino sugar(TAS),were studied,the main mostly conclusion as follows:Fertilization had little effect on the physical and chemical properties of purple soil,excessive application of chemical fertilizer would lead to a significant decrease in soil p H,long-term absence of fertilizer(organic fertilizer or chemical fertilizer)would reduce the content of organic matter in red soil,while single application of chemical fertilizer would significantly reduce the content of organic matter in purple soil,OMT and OMR treatments were sufficient for the supply of total nitrogen in quaternary red soil;NPKT and NPKR treatments significantly increased total P and available P in the three types of soil,while CKT,CKR,OMT and OMR treatments had similar contributions to total P in the three types of soil,but there was no significant difference between them;the available K content of OMR and NPKR treatments was the highest among the three soils,the contribution of OMT and OMR treatments to microbial biomass carbon was similar to that of NPKT and NPKR treatments,and the microbial biomass carbon content of CKT treatment was significantly lower than that of other treatments.Fertilization treatment had a great effect on soil physical and chemical properties,which were affected by soil type,fertilization treatment and their interaction.Under NPKT and NPKR treatment,?G,?X,LAP and AP in purple soil were significantly increased,while ?G,?G,?X,CBH and NAG in granite red soil and quaternary red soil were significantly increased.Carbon invertase ?g and ?G in purple soil and quaternary red soil treated with organic fertilizer(OMT,OMR)had no significant difference compared with CKT,but the granitic red soil was significantly higher than CKT.The enzyme activities of purple soil and granite red soil were mainly affected by MBC and MBN,while the enzyme activities of quaternary red soil were mainly affected by p H and SOC.The parent material and fertilization type have certain influenced on the content of amino sugar in soil,the accumulation of amino sugars from fungi was much higher than that from bacteria,and the content of total amino sugars in granite red soil was the highest.The contents of total amino sugars in Quaternary red soil and purple soil,SOC and sand had important effects on the accumulation of amino acids and sugars in soil.In conclusion,NPKT and NPKR deal with a large surplus of phosphorus,which may cause environmental risks,and their amino sugar content decreased significantly,which was not conducive to soil stability and organic carbon accumulation;while the OMT and OMR processing amino sugar content were significantly increased and nutrient element does not appear too much,so we should be based on the reduced fertilizer inputs,as well as input straw,to achieve balanced fertilization and promote the generation of stable organic carbon.