Effects Of Organic Materrials Alternatives Fertilizer On The Active Components Of Organic Matter In Red Soil And Purple Soil In Upland

Ecological degradation has occurred seriously in the red soil areas of China,for instance,organic matter decline,acidification,compaction and depletion.The purple soil in Sichuan Province is rich in base ions,rapid in soil formation and had a wide area for planting,however,it is seriously eroded,shortage of organic matter,loss of soil and water nutrients and difficult in improving the crop yield.The excessive use of chemical fertilizer,and the irrational disposal of agricultural wastes such as livestock manure,crop straw and farmland residual film are the main reasons for the decline of soil quality.In this study,red soil in Jiangxi Province and purple soil in Sichuan Province were selected as soil samples,and different kinds of organic materials combined with deduction of chemical fertilizers were used to investigate the effects of organic materials on crop yield and the active components of soil organic matter.The fertilization experiment of red soil and purple soil were started from 2015.The red soil in Jiangxi Province was a double-cropping system planted with sweet potato in summer and rape in winter.Nine fertilization treatments were set up for this soil,including control(CK),chemical fertilizer(CF),reduction of chemical fertilizer(RF),chemical fertilizer plus straw(CFR),reduction of chemical fertilizer plus straw(RFR),chemical fertilizer plus biochar(CFB),reduction of fertilizer plus biochar(RFB),reduction of chemical fertilizer plus pig manure(RFP),and reduction of fertilizer plus vermicompost(RFV).The cropping system in Sichuan Province is the rotation of Purple sweet potato in summer and purple potato in winter.Seven fertilization treatments were set up for this site,including control(CK),conventional fertilization(CF),conventional fertilizer plus straw(CFS),reduction of chemical fertilizer plus microbial organic fertilizer(RFM),reduction of chemical fertilizer plus wormcast compound organic fertilizer(RFV),reduction of chemical fertilizer plus straw and microbial organic matter(RFSM),reduction of chemical fertilizer plus straw and wormcast compound organic fertilizer(RFSV).The plough layer soil samples were investigated for three consecutive quarter to study the effects of different organic materials combined with reduction of chemical fertilizers on crop yield and the active components of soil organic matter.The main results are shown as follows.In Jiangxi Province,the crop yield in the treatments of organic materials combined with reduction of chemical fertilizer was higher than in the conventional fertilizer treatment.The rapeseed yield was significantly increased by RFP and RFV treatments compared with CF treatment(P<0.05).Compared with CF treatment,the addition of organic compounds modified soil pH,increased the cation exchange capacity and increased the contents of soil alkaline hydrolysis nitrogen,available phosphorus and available potassium.Besides,the treatments of organic materials combined with reduction of chemical fertilizer increased soil microbial biomass(MB),water soluble organic matter(DOM),particulate organic matter(POM)and readily oxidizable organic matter(LOM)content compared with CF treatment.The POM content in the addition of organic materials significantly increased the proportion of active components in the total soil organic matter,especially in the treatments of pig manure and earthworm manure;Correlation analysis showed the active components of SOM and organic matter were positively correlated with crop yield(P<0.05)after three seasons of fertilizer application.Furthermore,MB,POM,LOM had a very significant positive correlation with SOM(P<0.01).The three-dimensional fluorescence analysis of soil DOC showed that addition of organic compounds gradually dissolved the fluorescence peaks and Aromatic protein fluorescence peaks of soluble microbial metabolites and only the class of humic acid-like material fluorescence peaks and fulvic acid-like material fluorescence peaks were observed after three seasons of fertilizer application.Besides,the addition of organic compounds significantly increased the three-dimensional fluorescence index,changed the structure of DOC and promoted the transformation of protein-like material into humic acid-like material and fulvic acid-like material.In Sichuan Province,the crop yield in the treatments of organic materials combined with reduction of chemical fertilizer was similar as the CF treatment in the first two season.However in the third season,the crop yield was significantly increased by the treatments of organic materials combined with reduction of chemical fertilizer,and CFS treatment had the highest crop yield.Compared with CF treatment,addition of organic compounds significantly reduced the soil alkalinity,but increased the soil cation exchange capacity and available nutrients contents.After three quarters of fertilization,the active components of soil organic matter were greatly improved,especially in the RFSM and RFSV treatments.The organic matter components in the latter quarter were significantly increased compared with the previous quarter.The application of different organic materials can increase the proportion of organic components.The correlation analysis showed that the active components of organic matter and total organic matter were significantly correlated with crop yield,and the correlation was increased with the increasing of fertilizer season.Three dimensional fluorescence analysis of soil DOC showed that humic acid-like material and fulvic acid-like material were the main types of DOC in the purple soil.After three quarters of fertilization,humic acid-like material and fulvic acid-like material were increased,and DOC organic matter was mainly derived from microbiological activityIn conclusion,reducing 40%and 50%chemical fertilizer combined with the addition of straw,biochar,pig manure,earthworm manure,microbial organic fertilizer and earthworm bioorganic compound fertilizer can improve the crop yield and active components of soil organic carbon in both the red and purple soils.Therefore,deduction of the chemical fertilizer and addition with organic materials can not only improve crop yield,but also increase the active component of soil organic matter,improve the structure of organic matter and soil physicochemical properties.