Influence Research On Tobacco Residues Decomposition, Soil Nutrients, Enzyme Activities And Microorganism

In this research, the decomposition rate of the different tissues of tobacco residues, nutrient releasing, and the impact of soil nutrients, enzyme activities and microorganism was studied based on the method of nylon mesh bags. Its purpose is to provide a theoretical basis and technical supports for tobacco nutrient management and agricultural production management measures. The main results of this research are as follows:1.35℃and conventional water (moisture content60%～70%) was the suitable conditions of the three kinds of tobacco decay decomposition. The decomposition rate and the biomass of this three kinds of tobacco residues in this temperature and moisture conditions was higher than10℃,25℃,drought and soaking conditions.2. The decomposition rate of tobacco residues was quick in early times well slow in later time. During the whole experiment period (100days), the accumulation decomposition rates of the residues of tobacco leaves, tobacco stems and tobacco roots were53.04%,46.48%and36.66%, tobacco leaves residues>tobacco stems residues> tobacco roots residues. The three residues in the nutrient releasing were performed for K>P>C>N, but there were differences among these three residues. The rate of carbon releasing was performed for tobacco leaves residues> tobacco stems residues>tobacco roots residues; the rate of N releasing was performed for tobacco roots residues>tobacco leaves residues> tobacco stems residues; the rate of P releasing was performed for tobacco roots residues>tobacco leaves residues> tobacco stems residues; K releasing rate showed no differences between three kinds of tobacco residues.3. Tobacco decay could increase soil organic matter and available nutrient content, but the effect on the total content of nitrogen phosphorus potassium was not obvious. After100days of culture, the soil organic matter were increased3.27g/kg,3.30g/kg and3.18g/kg after tobacco leaves, stems and roots residues decay; alkali hydrolysable nitrogen contents were increased4.94mg/kg,4.06mg/kg and5.04mg/kg; available phosphorus contents were increased7.49mg/kg,6.78mg/kg and 6.65mg/kg; available potassium contents were increased22.10mg/kg,20.01mg/kg and14.86mg/kg; the available potassium content increased significantly. There are differences in the effect on the course of soil nutrient content between these three residues:alkali hydrolysable nitrogen was performed for tobacco roots residues> tobacco leaves residues>tobacco stems residues; available potassium was performed for tobacco leaves residues>tobacco stems residues>tobacco roots residues; the effect on the content of soil organic and available phosphorus showed no differences between three kinds of tobacco residues.4. Tobacco decay could affect the activities of soil catalase, urease, cellulose and phosphatase. The catalase activities showed increased first and then decreased and then increased trend, the changes had no significant differences between three residues. Tobacco residues decomposition affected soil urease activities were as follows:tobacco roots residues>tobacco leaves residues>tobacco stems residues; the activities of cellulose was similar as catalase, showed increased first and then decreased and then increased trend; tobacco residues decomposition affected soil cellulose activities were as follows tobacco stems residues> tobacco leaves residues>tobacco roots residues;tobacco decay could inhibit the activities of soil phosphatase, but the activities of soil neutral and alkaline phosphatase showed increased trend in late, three kinds of enzyme activities intensity were as follows:acid phosphatase> neutral phosphatase> alkaline phosphatase.5. Tobacco decay could promote increasing the quantity of soil microbial, and it would increase more in early times than later times, the number of these three microorganisms were as follows:bacterial>actinomyces>fungi. There were differences on the effect of soil microbial quantity between these three residues, the number of bacterial was the largest in the soil after tobacco leaves decay; the number of actinomyces was maximum in the soil after tobacco stems decay; well there was more effect on the influence of fungal after tobacco roots decay.