Research On Effects Of Different C/N Ratios On Fermentation Of Organic Fertilizers

This study mainly analyzes the effects of variable materials composition on fermentation temperatures, oxygen, compost volume, organic fertilizer quality indices, micro-organism quantity variation, harmful organism and control indices for flue-cured tobacco quality with natural resources (self-produced organic fertilizer) under actual production conditions (surface) in the tobacco production areas in Zunyi, and conclusions can be made as follows:1、Effect of different C/N on the fermentation effect of organic fertilizerIn this study, cattle manure and corn straws are selected as the main materials sources within the same fermentation processes. The results show that when the C/N ratios range from 20-35:1, the control indices of the ultimate organic fertilizers products, with the organism levels, the total nutrients levels, PH and harmful organisms (mould, colibacillus, roundworm ova) included, all meet the requirements of the organic fertilizers standards issued by the Ministry of Agriculture (NY525-2002). This facilitates the flexible selection of materials composition based on the resources variation of cattle manure and corn straws in these areas. The ratios of corn straws to cattle manure (dry weight ratios) could be 5:5,6:4, 7:3,8:2 in which the fermentation of organic fertilizers is the most effective when C/N ratio comes to 25:1 (corn straws:cattle manure is 6:4), which is beneficial for the growth and reproduction of bacteria and funguses in the fermentation process, the increase of days in which the temperature is over 50℃, the killing of harmful organism as well as the high levels of finished products rates. Alternatively, urea, as complementary nitrogen sources, of 7.6kg,11.0kg,14.4kg and 17.9kg could be added to per 1000kg dry materials (the total of cattle manure and corn straws, equivalent to fresh weights of 3000kg) respectively with corn straws to cattle manure composition of 5:5,6:4,7:3,8:2 to realize the C/N ratio of 25:1.2、Application effect in field of different C/N organic fertilizer(1) When the nitrogen level remains the same, the organic fertilizers with four different C/N formulas could all improve the top-class and top-and-medium-class tobacco ratios to different degrees, in which the organic fertilizers products could significantly improve the tobacco yields per mu when C/N ratios range from 23～30:1. Except for the organic fertilizers products whose C/N ratio is 30:1, other organic fertilizers treatments have no significant effects on tobacco outputs.(2) The effectiveness of organic fertilizers with different C/N formulae on the total sugar and reducing sugar levels of the top and medium-class tobaccos are shown as 25: 1>20:1>30:1>35:1; the organic fertilizers products with C/N formulae of 30:1 and 35:1 are much higher effective on total nitrogen and nicotine levels in the tobacco than that of 20:1 and 25:1; the protein levels in the different treatments are relatively high while the potassium and chlorine levels are moderate with little differences among the treatments. The sugar alkali and NIT/NIC are relatively low in different treatments with bad coordination. All in all, apart from the treatment of 35:1 significantly affecting the chemical components in tobacco, other treatments are all applicable for the flue-cured tobacco.(3) Organic fertilizers with different C/N formulae affect differently the aroma component levels as well as the total aromas components in tobacco. Organic fertilizers with C/N formulae of 25:1,30:1 and 35:1 could significantly raise the levels of propionic acid, 2-methylpentanoic acid, heptylic acid, furfuryl alcohol, dihydro-2-methylfuranone, neophytadiene, damascenone, geranylacetone, farnesyl acetone, megastigmatrienone4 and megastigmatrienone2 in tobacco while other components levels go up or down. Both the total acidic aroma components under C/N formulae of 20:1、25:1、35:1 and the total neutral aroma components under C/N formulae of 25:1、30:1、35:1 are higher by contrast. In general, organic fertilizers with C/N formulae of 25:1、30:1、35:1 could significantly raise the aroma index and the aroma index β values.