Effects Of Direct Straw Returning In Winter On Soil Properties And Rice Growth

In order to make better use of straw resources and improve the degradation efficiency of straw directly returning to the field in winter,in this study,the direct returning of straw to the field and the application of low-temperature microbial consortium were used to accelerate the degradation of straw.In the second year of planting,the soil properties,soil nutrients,soil microbial community characteristics,and rice growth and yield of the experimental base were investigated.This experiment was carried out in Zhenlai County,Jilin Province,in October 2019,where the average temperature in winter was-18℃～-5℃,and the soil type of the experiment site was saline-alkali soil.In this study,soil was treated with rice straw direct returning(SM),rice straw combined with low temperature straw degrading bacteria direct returning(SMJ)and control group(CK)in winter.During the three periods of seedling stage,tillering stage and harvest stage,soil organic carbon(SOC),humus,microbial biomass,total nitrogen(TN),and alkaline hydrolyzed nitrogen(AN),total phosphorus(TP),available phosphorus(AP),total potassium(TK)and available potassium(AK)and other nutrients and microbial diversity and abundance were measured.Plant height,aboveground dry weight,number of tillers and effective panicles were recorded at the tillering stage of the rice.The yield per hole of the rice was recorded at the harvest stage.SOC,MBC,TK and AP in each treatment group showed a trend of first increasing and then decreasing in different growth stages,and reaching the maximum value at the tillering stage.Compared with CK,SM and SMJ significantly increased soil enzyme activities and nutrient element contents,including SOC,TN,AN,TP,AP,TK and AK.Compared with CK and SM,SMJ significantly decreased soil p H.The activity of cellulase and invertase activities in soil is SM>SMJ>CK,while the activity of urease and protease activities is SMJ>SM>CK.The results of soil microbial characteristics showed that there were no significant changes in the composition and diversity of bacterial communities in the three groups.The fungal community composition of SM and SMJ changed significantly compared with CK.It can be seen that straw returning has little effect on the structure of soil bacterial flora in short term,but significantly affects the biological characteristics of fungi.Plant height,tiller number,effective panicle number and terrestrial dry weight in SM and SMJ groups were significantly higher than those in CK group.Especially in the SMJ group,the increase was more significant.Compared with the CK group,the tiller number,effective panicle number,and single output in SMJ group increased by 89.53%,108%,and14.96%,respectively.Compared with the SM group,the tiller number in the SMJ group increased by 40%,the effective panicle number increased by 47.06%,and the yield per hole increased by 9.78%.These results indicate that the low-temperature microbial consortium and the co-returning of straw can improve the degradation efficiency of straw in the process of direct returning to the field at low temperature in winter.The co-incorporation of a low-temperature microbial consortium and straw-return can improve soil fertility,promote rice growth and increase rice yield.