Effects Of Straw Returning And Biogas Slurry On Rice-wheat Rotation Production And Soil Quality

In agricultural production of our country,the application rate of chemical fertilizer is large and the utilization rate is low.Besides,the investment in organic fertilizers is not paid enough attention.This has caused problems such as waste of resources,decline in soil fertility and ecological damage to farmland.There are abundant straw and biogas slurry resources in China.If the methods are used properly,they can promote social and economic development and improve the ecological environment in coordination.Therefore,it is the key to reduce fertilizer application and increase efficiency in our country to seek scientific and reasonable fertilizer mode and develop organic fertilizer instead of chemical fertilizer.Field location test was conducted to explore the effects of straw and biogas slurry on rice and wheat yield,soil fertility and soil ecology under the system of rice and wheat rotation.In this study,10 different treatments were set up with different chemical fertilizer substitution levels.The main conclusions of the study are as follows:In rice season,biogas slurry instead of chemical fertilizer continuously consumes soil nutrients and fails to improve soil fertility.Compared with other treatments,the contents of soil organic matter,total nitrogen,alkali-hydrolyzed nitrogen,total phosphorus,available phosphorus and available potassium in rice season and wheat season were effectively increased by applying biogas slurry instead of chemical fertilizer.Compared with rice season,organic fertilizer instead of chemical fertilizer increased soil organic matter and available potassium content.Straw biogas slurry instead of chemical fertilizer can increase the yield of rice and wheat,and has a certain impact on the yield components.Replacing 30%chemical fertilizer with organic fertilizer is the better mode of combined application.The activity of soil enzyme was decreased by applying chemical fertilizer alone.The activity of AG,BG,CB,XYL,NAG,LAP,PHOS,PHOX and PEOX was increased by adding straw to the field.Straw returning to the field enhanced the ability of soil nutrient transformation and resistance to stress.Straw and biogas slurry instead of 50%chemical fertilizer(S+BSF2)were the best among different treatments.Through high-throughput sequencing and combined with soil physical and chemical properties for redundancy analysis,it was found that Proteobacteria,Green Curvature,Acidophilus,Actinobacteria and Bacteroides are the dominant bacteria in the soil.However,due to the influence of soil physical and chemical properties,the relative abundance of different bacteria is different.Organic matter and total nitrogen are the main influencing factors in the rice season,and total phosphorus is the main influencing factor in the wheat season.What’s more,Ascomycota is the dominant fungal flora of rice and wheat rotation.Organic matter is the main environmental factor in rice season.Total nitrogen and alkali nitrogen are the main environmental factors in wheat season.In summary,Straw and biogas slurry suitable ratio instead of fertilizer,can achieve stable yield and increase yield,increase soil nutrients,improve soil enzyme activity.And the composition of microbial communities was similar in different treatments,but the relative abundance of different microbial communities was different under the influence of fertilization methods.