Study On The Effect Of Microorganisms On Saline-Alkali Soil Improvement

In order to investigate the improvement effect of microbial agents and microbial bacteria on saline soils in Ningxia yellow irrigation area,we applied different amounts of microbial agents and microbial fertilizers to investigate the effects on salinity,moisture and nutrients of saline soils through outdoor dry rice pot planting test and indoor soil column simulation test,and investigated the characteristics of water infiltration and parameter changes of microbial fertilizers on saline soils.(1)Microbial bacterial agent was treated in two different ratios and microbial fertilizer was treated in three different ratios,and the treated soil was tested in a potted dry rice planting experiment to compare and analyze the effect of the treatment group on plant height during the seedling stage of dry rice,the effect of the treatment group on soil nutrients of dry rice during the fertility stage of dry rice,and the effect on the salinity and soil pH yield of potted dry rice.The test results showed that:compared with the control group,the F2 and T3 treatment groups could increase the plant height of dry rice seedling stage by 94.85%and 96.08%;compared with the control group,the T3 treatment group increased dry rice yield by 63.41%,reduced soil salinity by 36.27%and reduced soil pH by 4.4%;both microbial fungicide and microbial fertilizer application increased soil nutrients.(2)The microbial fungicides were treated in five different ratios,and the treated soils were subjected to soil column tests and potted oleander tests to compare and analyze the changes in soil water content,salt content,soil structure and the effects on the growth of oleander before and after treatment.The test results showed that:compared with the control group,the content of water-stable aggregates could be increased by 82%at the maximum after treatment;the water content of soil after treatment was greater than that of the control group,and the maximum growth rate could reach 25.32%;the water capacity of soil after treatment was greater than that of the control group in different suction;the salinity of soil after treatment was significantly reduced,and could be reduced by 57%at the maximum;the quick-acting nitrogen,quick-acting phosphorus,ammonia nitrogen and Nitrate nitrogen increased by 72.32%,68.64%,73.49%and 79.27%respectively;after treatment,the soil was planted with oleander and compared with the control group,both oleander stem thickness and leaf surface area were improved.Microbial fungicides not only improve the content of soil waterstable agglomerates,but also increase the water retention performance of soil,which makes soil water-holding and water-supply capacity enhanced,and can reduce soil salinity and increase soil nutrients,thus effectively promoting the growth of crops.(3)Microbial fertilizer,five groups of application rates were set,and the indoor one-dimensional vertical soil column infiltration method was used to compare the infiltration patterns of three infiltration models after adding microbial fertilizer by observing the changes of cumulative infiltration and wetting front transport patterns,and the numerical simulation of soil profile water content according to the one-dimensional algebraic model.The experimental results showed that:compared with the control group,microbial fertilizer application slowed down the moisture front transport process while interacting with saline soils to reduce soil pH;the cumulative infiltration time increased with microbial application;the soil profile salinity decreased with the increase of microbial application at the same soil depth;the magnitude of the coefficient of determination R2 of the three infiltration models was compared to determine the applicability of the models.The application of microbial fertilizer can slow down the water infiltration process and reduce the soil pH,and the infiltration process can be better simulated by Green-Ampt model,Kostiakov model,and Philip model.The application of microbial bacteria can reduce the salinity of saline soil,and the onedimensional algebraic model can better simulate the change of water content of soil profile in different treatments from the simulated and measured values.The addition of microbial fungicides and microbial fertilizers can effectively improve the water movement characteristics of saline soils,regulate the soil water distribution and promote crop growth.The research results of this paper can provide a scientific and theoretical basis for improving saline soils in the yellow irrigation area of Ningxia.