The Application And Compounding Of Straw Biogas Slurry On Vegetables

Livestock and poultry manure biogas slurry agricultural use has a relatively complete system and mature measures,and straw biogas slurry treatment is still based on simple discharge,but the straw biogas slurry because it contains water-soluble nutrients,soluble organic matter and other substances,direct discharge easy to cause environmental problems,whether it can be used as livestock and poultry manure biogas slurry fertilizer utilization and how to fertilizer utilization,there are few research reports in this area.On the basis of determining the application effect and appropriate concentration of biogas slurry fertilizer,this study developed the application formula of biogas slurry fertilizer by applying trace elements and fertilizer synergist on leafy vegetables(cabbage)and solaniferous vegetables(pepper),and provided the basis for agricultural fertilizer application of biogas slurry.The main results are as follows:(1)The p H of biogas slurry used in this experiment is 8.26,which is alkaline.The contents of TN,TP,TK,Cr and Pb were 2.64～4.38,2.31～3.95,2.56～5.40,1.42～2.36,2.91～10.87 and 2.04～6.35 times of those of livestock and poultry biogas slurry,respectively.(2)biogas slurry can promote the growth and development of vegetables and improve the yield and quality of vegetables.On the premise of high yield and high quality of Chinese cabbage,the application concentration of biogas slurry was 16.67% to 21.02%.In this concentration range,the root activity,yield and nutrient content of Chinese cabbage were higher,while the heavy metal content was lower.After three consecutive seasons of biogas slurry application,compared with the control,soil p H increased by 1.11 units,EC value,organic matter content,water content,porosity increased by 19.45%,23.52%,32.97%,28.94%,respectively.Soil bulk density,alkali-hydrolyzed nitrogen,available phosphorus and available potassium contents decreased by 16.03%,9.75%,12.62% and 3.97%,respectively,compared with the control.(3)Application of trace elements in biogas slurry had significant effects on growth,high yield and high quality of vegetables.The seedling strength index of pepper and Chinese cabbage increased by 17.24% and 29.85%,respectively.Compared with the control,the yield,VC and soluble protein contents of pepper and Chinese cabbage increased by 7.76%,24.20% and 25.73%,17.78%,21.97% and 42.11%,respectively.28.98%,31.93%,33.44%,nitrate content decreased by 20.51%,26.42%,24.78%,respectively.On this basis,fertilizer synergist was applied to promote the prematurity and prematurity of capsicum,and significantly increased the soluble sugar content of capsicum and two seasons of Chinese cabbage by 24.58%,23.96% and 17.41%,respectively.For solanum vegetables that pursue sweetness and flavor,prematurity and prematurity,the compound way of biogas straw + trace elements + fertilizer synergist can be adopted.(4)The application of straw biogas slurry increased the content of heavy metals in crops and soil.The application of straw biogas slurry had no significant effect on the heavy metal content of capsicum,but significantly increased the heavy metal content of cabbage in two seasons.Compared with the control,the contents of As,Cd,Cr,Cu,Hg and Pb in cabbage increased by 18.07%,13.27%,7.61%,9.04%,11.84% and 19.75%,respectively.22.13%,17.53%,12.75%,8.60%,14.97%,29.57%.The contents of As,Cd,Cr,Cu,Hg and Pb in soil increased by 7.69%,9.29%,11.49%,10.29%,20.08% and23.56%,respectively,compared with the basic value after three consecutive application of straw biogas slurry combined with trace elements.The heavy metal content of all treated vegetables and soil samples in this experiment was lower than the limit of heavy metal content of relevant standards in China.In conclusion,the concentration of biogas slurry applied should be controlled in the range of 16.67% to 21.02%.No matter the application of biogas slurry or the application of trace elements combined with biogas slurry,the overall effect of promoting the yield and quality of pepper and cabbage is cabbage > pepper.At the same time,different biogas slurry compounding modes should be selected according to the production objectives.In order to pursue vegetable yield,the biogas slurry + trace elements compounding mode can be used.In order to pursue vegetable quality,the mixture of biogas slurry + trace elements + fertilizer additives can be adopted.In addition,with the increase of the cumulative application amount of biogas slurry,heavy metal content in soil and vegetables also increased,and the enrichment ability of heavy metals in leafy vegetables was higher than that in jacket vegetables.Therefore,when the risk degree of heavy metals in soil was high,jacket vegetables were preferentially planted.