CO₂ Enrichment By Fermentation Of Agricultural Organic Wastes And The Utilization Of Its Residue

With the rapid development of agriculture and stock raising, plenty of agriculturalwastes, such as straw, livestock and poultry manure were produced. The environmenthas been seriously polluted by their out-of-order letting off. So it is a big problem thathow to deal with these wastes. Besides, the deficiency of CO₂, soil degradation,soil-borne diseases and continuous cropping obstacle has become the importantfactors affecting the quality and yield of the vegetables in the greenhouse, In thisresearch, the effects of CO₂ enrichment by fermentation of organic wastes on the yieldand quality of tomato, strawberry, letteuce and celery in the greenhouse, and theeffects of compost mixed with some functional microorganisms on alleviating theproblem of the continuous cropping soil in indoor cultivating experiment were studied.In conclusion, CO₂ enrichment via the fermentation of agricultural organic wastes inthe greenhouse and solving the problem of soil degradation by the compost left wouldprovide a new technical system at last. The results obtained from experiments are asfollows:1. Effects of CO₂ enrichment by fermentation of organic wastes on the yield andquality of vegetables in the greenhouseThe yield and quality of tomato, strawberry, lettuce and celery was studied underCO₂ enrichment via the fermentation of agricultural organic wastes (swine feces andrice straw) in the greenhouse.The yield of vegetables in the greenhouse could be significantly increased by CO₂enrichment via fermentation of organic wastes. The yield and income of tomato,strawberry, lettuce and celery was increased by 43.8%, 37.2%, 32.7%, 37.5% and68.8%, 46.2%, 36.3%, 39.2% respectively. Furthermore, 15 days and 7 days predatedfor harvest for tomato and strawberry Besides, the quality of the vegetables was alsosignificantly improved. The contents of soluble sugar of tomato, strawberry, lettuce and celery were increased by 28.5%, 30.2%, 14.0% and 12.5% respectively. Thecontents of vitamin C of tomato, strawberry, lettuce and celery were increased 16.4%,18.6%, 36.4% and 44.1%. The contents of soluble solid of tomato and strawberrywere increased by 33.4% and 34.5%, and the ratio of sugar/organic acid was alsoincreased by 73.6% and 37.0%. At the same time, the nitrate contents of tomato,strawberry, lettuce and celery were significantly decreased by 9.3%, 68.4%, 36.4%and 44.1%. The contents of organic acid of tomato and strawberry were decreased by35.0% and 5.2%, then the ratio of sugar/organic acid was increased from 9.3 and 14.0to 16.2 and 19.2, respectively.2. Effects of the compost mixed with microorganisms on the improvement ofcontinuous cropping soil in the greenhouseUnder the conndition of different temperatures, the effects of two microorganismsisolated by ourselves (By), commercial microorganism (EM), and the mixedmicroorganism (EM+By) on the growing speed of microorganism in the compostwere studied in this research. An indoor soil cultivating experiment was carried out tostudy the effects of different microorganisms on alleviating the problem of thecontinuous cropping soil. The fowllowing results were got out:Between 30℃,40℃and50℃, the number of the microorganisms in the compostwas the most in 40℃.Except for 50℃, the number of the microorganisms increasedas the cultivating time gone, and on the seventh day it increased to the most.The value of pH was significantly increased, 5 weeks after cultivating the value ofpH was the most in (EM+By), which was 6.39, 1.14 more than that of control. Theeffects of different microorganisms on activating the nutrients of compost weredifferent in enriching period. And the effects of different microorganisms onactivating the nutrients of soil were also different during cultivating period. By theend of cultivating period, the contents of available N, P and K were significantlyincreased. The effects of different microorganisms on activating the nutrients of soilwere EM＞(EM+By)＞By, EM＞EM＞By and EM＞EM＞By.The number of bacteria, actinomyces, euacteria and the ratio of bacteria/euacteriawas significantly increased. And that of (EM+By) was increased most compared with other treatments. So it has made a great difference in improving the structure of soilmicroorganism.The soil urease and acid phosphatase activity was the most in (EM+By) treatment,increased by 26.7 mg (NH₄-N) kg^-1 d^-1, 127.0 mg ( hydroxybenzene ) kg^-1 h^-1compared with CK, respectively.3. Effects of compost inoculated with functional microorganisms on the yieldand quality of aftercrop cucumberIn field experiment, the effect of compost which corned from CO₂ enrichment fortamato mixed with By microorganism on the soil physical and chemical propertiesand the yield and quality of aftercrop cucumber was studied. The following resultswere got out:Not only the pH value of the rhizospheric soil but also that of the bulk soil wassignificantly increased, and the pH value was higher in bulk soil than that ofrhizopheric soil. The number of bacteria actinomyces, euacteria and the ratio ofbacteria/euacteria was significantly increased, and the number in rhizopheric soil wasmore than that in bulk soil. The contents of available N, P, K ,urease activity and acidphosphatase activity were significantly increased.The height and SPAD value of cucumber were significantly increased by compostmixed with microorganism, and the incidence of blasting disease of cucumber wassignificantly reduced. After harvest, the yield and income of cucumber were increasedby 39.3% and 40.0%. Besides, The contents of soluble sugar and vitamin C ofcucumber were increased by 62.8% and 37.5%. Moreover, the organic acid and nitratecontent were significantly decreased by 36.8% and 70.0%.