The Effects Of Organic Nutrients Of Cake Fertilizers On Soil Biochemistry Properties And Flue-cured Tobacco Qualities

The mechanism of the cake fertilizer affecting soil biochemistry properties and flue-cured tobacco quality was studied by the fermentation experiments, field experiments, pot experiments, water culture experiments and pipe experiments. The results will develop the scientific and technical theories for the tobacco nutrient, the rational fertilizer application, and the flue-cures tobacco quality improvement.1. The higher fatty acids, organic acids, amino acids and ferulic acids from the four fermented oil cakes were found. The organic substances and their dynamic regularity from the four oil cakes were analyzed during the fermentation.(1) The main compositions of organic substances from sesame seed cake, soybean cake, peanut seed cake and rapeseed cake were similar, but their contents changed significantly during the fermentation. The contents of linoleic and oleic acid were the highest and the following was palmitic, stearic and linolenic acid in the higher fatty acids of the four oil cakes, i.e. C₁₆ and C₁₈ acids were the dominant components in the higher fatty acids from the cake fermentation and the content of saturated acids was higher than the content of the unsaturated acids obviously. In the organic acids, the contents of lactic acid, malic acid, citric acid, succinic acid ,tartaric acid and acetic acid were higher than oxalic acid. The glutamate occupies the first place, aspartate ,leucine and arginine comes the second in all amino acids. Soybean and peanut cakes produced more amino acids than the others during the fermentation.(2) The dynamic regularity of organic substance contents of the four oil cakes was analyzed during the fermentation. The contents of almost the higher fatty acids and the organic acids inclined to increase in the initial fermentation stage, and reached the peaks in the different fermentation stages. However, the contents of total amino acids were significantly decreased after seventy days of fermentation.(3) The content changes of ferulic acid were determined during the oil cake fermentation. The range of the rapeseed cake ferulic acid content was from 48.6 to 49.2 μg/kg. When the soybean and peanut cakes were fermented for seventy days, the ferulic acid were 30.2 μg/kg and 85.7μg/kg respectively. While the least content(2.5⁵.4μg/kg) was from sesame seed cake.(4) The compost characteristics and the compost periods of the four oil cakes were described. At 28 , the suitable fermentation time of sesame seed cake was 30?0d, the soybean 50⁶0d, the peanut 50⁶0d, and the rapeseed cake 60⁷0d. These results suggested that the fermentation time should be controlled in farming based on the characteristics of fermentation and compost.2. The effects of cake fertilizers in soil were understood better by the following studies.(1) The cake fertilizers improved the enzyme activity in soil. When mixture fertilizer(cake fertilizer mixed with chemical fertilizer) was used in soil, the enzyme activities of lipase, urease and invertase from soil increased 24.85%⁶0.00%, 23.08%³9.46% and 4.17% 56.21% respectively. The results indicated that the cake fertilizer promoted the transferring process of soil organic matter, and improved the biochemical properties to meet nutrition supply during tobacco growth.(2) The application of cake fertilizers can raise the C and N contents of the microbial in soil, improve the soil regulating function on C and N. The mixture fertilizer increased C and N of the soil microbial, the increase rates were 79.88%⁹7.14% and 29.73%?4.96% respectively compared with only using chemical fertilizer. The microbial C content reached the peak at the budding stage of flue-cured tobacco. However, the peak of microbial N content appeared at the rosette stage. These showed the content of inorganic N was higher at the initial stage of plant growth, and some of soil inorganic N was fixed by microorganism. Microorganisms may release itself N to meet the need of flue-cured tobacco during the later growing stages. So the microbial N...