Study On The Effect Of Organic Materials And Plastic Film Mulching On Improving Saline Soil

The problem of soil salinization has seriously affected the efficient use of land.In order to improve the productivity of saline soil and improve soil fertility in Songnen Plain,a technology of synergistic improvement of saline soil with organic materials and plastic film mulching was designed to enhance the efficient use of saline soil.In this study,eight treatments were set up,including control（CK）,plastic film mulching（CKM）,chicken manure（J）,cow manure（N）,biochar（C）,chicken manure+plastic film mulching（JM）,cow manure+plastic film mulching（NM）,and biochar+plastic film mulching（CM）.The changes of organic carbon pool in saline soil under the synergistic effect of organic materials and plastic film mulching were analyzed.At the same time,the changes of soil humus composition and optical properties were explored.Combined with the dynamic changes of soil nutrients and the characteristics of soil salinization indicators,the effects of organic materials and plastic film mulching on the physical and chemical properties of alkaline aeolian sandy soil were discussed,and the growth and development of soybean under this technology were detected and analyzed.It provides certain technical support for scientific improvement of salinized soil.The study draws the following conclusions:1.The content of available nutrients in each treatment gradually decreased with time.The application of organic materials and film mulching could increase the content of available nitrogen,available potassium and available phosphorus in the soil,and the synergistic effect of organic materials and film mulching was the best.In August,soil available nitrogen and available potassium in JM treatment were significantly higher than CK（P<0.05）,and available phosphorus in CM treatment was significantly higher than CK（P<0.05）.In December,the contents of available nitrogen,available phosphorus and available potassium in each treatment increased compared with August.2.Each treatment can effectively reduce soil p H,electrical conductivity（EC）,exchangeable sodium ions,and alkalinity（ESP）,and increase soil cation exchange capacity（CEC）.Among them,NM treatment significantly reduced soil p H（P<0.05）and reduced soil EC;c M treatment significantly reduced exchangeable sodium content and ESP（P<0.05）,while C treatment had the best effect on improving CEC.Compared with August,p H and ESP in December showed a decreasing trend,while EC,CEC and exchangeable sodium ions showed an increasing trend.3.Each treatment effectively increased the content of soil organic carbon.In July and August,the cooperation between organic materials and plastic film reached a significant level,among which NM treatment had the most significant effect（P<0.05）.The effect of chicken manure and cow manure treatment on increasing the content of active organic carbon components was significantly higher than that of biochar and single film mulching treatment.Compared with CK treatment,dissolved organic carbon（DOC）,easily oxidized organic carbon（EOC）and particulate organic carbon（POC）in NM treatment increased by 50.36%,34.49%and 57.35%,respectively.The results of soil carbon pool management index（CPMI）showed that NM treatment had the most significant effect on CPMI（P<0.05）,which was more conducive to improving soil quality.Organic carbon was accumulated in December compared with August,the content of active organic carbon components increased,and CPMI increased.Correlation analysis showed that there was a significant positive correlation between EOC and TOC,and EOC could be used as a sensitive index to reflect the change of soil organic carbon.4.All improvement measures were effective in increasing the content of each component of soil humus,and the content of soil water-soluble matter（WSS）increased by 6.9%-73.3%,HA content increased significantly by 28.8%-164.18%,and HM content increased by 7%-160.52%,all of which were significant（P<0.05）with NM treatment to enhance the humus components;FA content increased by 21.73%-99.76%,but there was no significant difference among treatments compared to CK treatment.The effects of organic materials on PQ values（HA to humic acid ratio）and huminic and fulvic acid ratios(C_HA/C_FA)varied depending on the applied materials,with JM treatment having higher values.The analysis of hue coefficient（?Log K）showed that FA and HA tended to be younger and simpler with applied materials and mulch.the WSS,FA content and HA?Log K in soil humus increased and HA,HM,PQ values,C_HA/C_FA and FA?Log K decreased in December compared to August.5.The growth and development of soybean plants in all improvement treatments were better than the control,but the application of biochar and single mulch were less effective than manure in affecting all growth and development indicators of soybean.Both organic material alone and organic material with mulch were more effective than chicken manure and cow manure in increasing the number of soybean pods,with NM and JM treatments increasing the number of soybean pods by 116.82%and 135.45%,respectively,compared to the CK treatment,both of which were significantly different from the CK treatment（P<0.05）.Pod height increased by2.82%-17.85%,aboveground biomass increased by 2.11%-24.28%,and belowground biomass increased by 17.42%-156.21%compared to the CK treatment,all of which were most significantly increased by the JM treatment compared to the CK treatment（P<0.05）.And NM treatment had the most significant effect on increasing soybean stem thickness（P<0.05）.It can be seen that both organic materials and film mulching have good improvement effects,and the synergistic technology of organic materials and film mulching has the best improvement effect on each treatment.The synergistic technology of organic materials and film mulching can more effectively increase the content of soil organic carbon and its components,reduce soil salinity,increase soil nutrient content,and promote soil humification.The synergistic technology of chicken manure and plastic film was more effective in improving soil available nitrogen,available potassium and promoting soybean growth and development.The synergistic technology of cow dung and plastic film effectively increased soil organic carbon and its active organic carbon components,humus composition and carbon pool management index.The synergistic technology of biochar and plastic film is more conducive to reducing soil salinization,but the effect on other aspects is not significant.Therefore,the synergistic technology of film mulching and different kinds of organic materials will promote the improvement and fertility improvement of alkaline sandy soil more effectively,and realize the systematic improvement and efficient utilization of alkaline sandy soil resources.In the saline soil or other areas with similar soil conditions in Jilin Province,the use of organic materials and film mulching technology is a feasible measure to improve soil and increase soybean yield in saline soil.