Study On Anaerobic Fermentation Of Vegetable Straw And Comprehensive Utilization Of Biogas Slurry

As a large agricultural country, China has abundant biomass resources, including a largenumber of vegetables and straw waste. It will be polluted the ecological environment, andcaused a lot of resources abandoned if it is used unreasonable. With the adjustment ofindustrial structure and widespread promotion of households anaerobic fermentation in ruralareas, the traditional fermentation materials can not meet the need any more. Thedevelopment of new fermentation materails has become an urgent need for the majority ofrural biogas users. In this experiment, it studied the fermentation feasibility of severalcommon vegetable straw. The specific conclusions as follows:(1) Gas production is best when the concentration was8%on condition that the drymatter(TS) of watermelon straw and cow dung mixed at the ratio of1:1. When cucumberstraw as raw materials for anaerobic fermentation, the best feed concentration (TS) of freshcucumber straw fermentation was6%, the best feed concentration of dry cucumber strawfermentation was8%. The results showed that the gas production increased with theincreasing of feed concentration in a certain range. The gas production of fresh watermelonstraw mixed with cow dung in the early stage was larger than dry watermelon straw mixedwith cow dung. But in the late stage, the gas prodution of dry watermelon straw mixed withcow dung was larger. When the cucumber straw as the only raw material, the situation of gasproduction was similar.(2) The effect of gas production was best when the inoculum concentration of freshcucumber straw fermentation was30%, and the inoculum concentration was20%of drycucumber straw fermentation. The results showed that the inoculum concentration is too highor too low will not conducive to anaerobic fermentation.(3) In the process of anaerobic fermentation, the pH of fresh cucumber straw in theprocess of fermentation is lower than that of dry cucumber straw, and the acid-producingstage is longer. Therefore, the fresh raw material should be pretreated to prevent thefermentation materials acidification, and to ensure the gas production effect of anaerobic fermentation.(4) The experiment that the different top-dressing amount of biogas slurry on cucumbershowed that: biogas slurry as top-dressing fertilizer significantly increased the yield ofcucumber compared with the control treatment. The yield of the cucumber were the mostsignificant increased when the top-dressing amount of biogas slurry was2000kg/(667m2), itwas11.1%higher than that of control treatment. According to the quality indicator ofcucumber, the curved rate of cucumber was lowest and the solubble sugar content incucumber was highest when the top-dressing amount of biogas slurry was1800kg/(667m2).when the top-dressing amount of biogas slurry was2000kg/(667m2), the Vc content incucumber was highest and it was increased31%compared with the control treatment.Futhermore, the nitrate content in cucumber was lowest and it was decreased49.7%compared with control treatment when the top-dressing amount of biogas slurry was1200kg/(667m2). Therore, biogas slurry as top-dressing fertilizer can effectively improve theyield of cucumber and enhance the quality of cucumber.(5) The experiment of different top-dressing fertilization treatments on cucumbershowed that: the cucumber yield of the treatment of50%amount chemical fertilizer mixedwith biogas slurry foliar fertilization was15955kg/(667m2) which was highest and it was16.9%higher than that of control treatment. According to the quality indicator of cucumber,the curved rate of cucumber of the treatment (biogas slurry foliar fertilization) was lowest andit was19%lower than that of control treatment; the soluble sugar content in cucumber of thetreatment (50%amount chemical fertilizer mixed with biogas slurry foliar fertilization) washighest and it was90.8%higher than that of control treatment; the Vc content in cucumber ofthe treatment (50%amount chemical fertilizer mixed with biogas slurry foliar fertilization)was highest and it was25.9%higher than that of control treatment; the nitrate content incucumber of biogas slurry foliar fertilization treatment was lowest and it was decreased64.2%compared with control treatment, the nitrate content in cucumber of differenttop-dressing fertilizer treatments on cucumber has significant differences compared withcontrol treatment. The quality of cucumber used biogas slurry foliar fertilization,50%chemical fetilization mixed with biogas slurry foliar fertilization was better than that ofcucumber used biogas slurry irrigation and50%chemical fertilization mixed with biogasslurry irrigation.