Applocation Of Mixed Biogas Residue Substrates In Soilless Culture Of Vegetables

With the rapid development of economic,many natural resources have been unable or will not be able to meet the growing needs of mankind for human producing and living.Therefore,the development of clean energy has become the key to solving the contradictions between the development of the economy and the protection of the ecological environment in China.Biogas projects can replace non-renewable petrochemical energy with renewable biomass energy such as animal manure and plant straw,reduce the emission of greenhouse gases,to realize the utilization of waste resources,reduce the production costs,and contribute to the protection of the ecological environment,the biogas project has been rapidly developed.Biogas residue is a biological fermentation product of biogas engineering residues,it is rich in organic matter and microorganisms,China's biogas projects produce a lot of biogas residue every year.However,emissions directly will cause huge pollution to the environment,waste of resources,and have a certain impact on human healthy.In order to avoid the pollution of the biogas residue to the environment,realize the resource utilization of the biogas residue,reduce the use of non-renewable resources of peat,and reduce the cost of soilless cultivation,it is of great significance to study the biogas residue as a substrate for soilless cultivation.The mixed biogas residue substrate is an organic matrix formed by the biogas engineering residue as a basic raw material,which is formed by adding padding,mixing and stacking,and fully fermenting.In this experiment,biogas residues were mixed with different substrates such as vinegar residue and vermiculite in different proportions to improve the physicochemical properties of the biogas residue and applied to cucumber and tomato seedlings,to select the most suitable mixed biogas residue substrate formulation for cucumber and tomato seedling.The application of mixed biogas residue substrate in the cultivation of cucumber and tomato was studied in order to select the most suitable mixed biogas residue substrate formulation for cucumber and tomato cultivation.At the same time,non-heading cabbage was selected to explore the effect of mixed biogas residue substrate in soilless cultivation of non-heading cabbage.The main findings are as follows:1.We analyzed the physical and chemical properties of each single substrate,the pH and EC value of the biogas residue substrate are relatively high,the direct utilization is not conducive to plant growth,while the vinegar residue is acidic,but the porosity is large,the water holding capacity is weak,and the vermiculite has a strong water retention capacity.The biogas residue is mixed with different substrates such as vinegar residue and vermiculite in different proportions to improve the physical and chemical properties of the biogas residue so as to meet the requirements for suitable plant growth.The contents of P,Ca and other elements increase as the amount of biogas residue increases in the mixed biogas residue substrate,the heavy metal element of Zn content in pure biogas residues exceeds the national safety standards,after compounding with other matrices,all heavy metal elements are below the national safety standards.The mixed biogas residue substrate A3(biogas residue:vinegar residue:vermiculite?4:4:2)had higher seedling emergence rate,root activity,chlorophyll content and net photosynthetic rate in cucumber seedlings,the seedling emergence rate,plant height,stem diameter,root activity,chlorophyll content and net photosynthetic rate of the mixed biogas residue substrate A,5(biogas residue:vinegar residue:vermiculite=2:6:2)were higher in tomato seedlings.Therefore,biogas residue:vinegar residue:vermiculite=4:4:2 mixed biogas residue substrate can be used as a substrate for high quality cucumber seedlings,biogas residue:vinegar residue:vermiculite=2:6:2 mixed substrate can be used as a substrate for high quality tomato nursery.2.The mixed biogas residue substrate was used as the substrate for cucumber and tomato cultivation.The results showed that the activities of urease and sucrase were significantly higher than the control.The water retention capacity of the biogas residue is strong,and the content of water in each mixed biogas residue substrate decreases with the decrease of the biogas residue addition amount.Tomatoes grow normally in AO(pure residue),while cucumbers die quickly after transplanting.The contents of soluble sugar,soluble protein,Vc and yield of cucumber and tomato cultivated with A3(biogas residue:vinegar residue:vermiculite=4:4:2)were significantly higher in all treatments,and higher than the control,the contents of heavy metal elements in cucumber and tomato leaves were lower than the national vegetable standards.3.The mixed biogas residue substrate was used as the substrate for the non-heading Chinese cabbage cultivation,the test results showed that the emergence rates of non-heading cabbage in different mixed biogas residue substrates were low,Therefore,the mixed substrate of biogas residue was not suitable for the cabbage seedling substrate.In the non-heading cabbage cultivation test,A4(biogas residue:vinegar residue:vermiculite=3:5:2)and A5(biogas residue:vinegar residue:vermiculite=2:6:2)mixed biogas residue substrate can significantly improve the non-heading cabbage production,however,the contents of soluble sugar,soluble protein and Vc in the non-heading cabbage cultivate by A4(biogas residue:vinegar grains:vermiculite=3:5:2)formula were significantly higher than those by A5(biogas residue:vinegar bad:vermiculite=2:6:2),and the content of heavy metals in each treatment were lower than the national vegetable standards.