| Soil is the basis for the production of high-quality tobacco. Long succession cropping and application of fertilizers make soil environment seriously damaged and degradation, effective and sustainable use of the land resource are affected, led to the quality of tobacco and industry availability and the efficiency of tobacco decreased, Improve and maintain soil quality is of great significance to the promotion of tobacco production and sustainable development. Using the method of nylon net bag simulated green manure and the stalk returned to soil, to explore the decomposing rate of green manure and straw and the release characteristics of organic matter, nitrogen, phosphorus and potassium. Green manure, stalk and decomposition maturing agent to explore the effects on the physic-chemical properties of the soil, the growth and development of tobacco and the quality of flue-cured tobacco, Thus screened out the suitable program for straw and manure returned to filed. The main conclusions are as follows:(1) Dynamics of the organic matter decomposition and nutrient release for green manure in tobacco fields of Xiangxi The dynamics of nutrient release and organic matter decomposition of smooth vetch,common vetch,milk vetch, perennial ryegrass as green manure were studied in tobacco fields, which the green manure were wrapped in net nylon bag sand embedded in plow layer in tobacco fields. Results showed that ? the relationship between the organic matter decomposition and nutrient release in green manure and decomposing time might be fitted by a logarithmic equation, their decomposing rates were divided 3 stages, it was the fastest in the first two weeks, and then from 3 to 7 weeks, obviously slow after the seventh week. ?The accumulative decomposing rate of the organic matter, C, N, P, K to 49d was 60.64%?70.57%,62.17%?71.32%,75.68%?83.03%,70.61%?84.78%,73.88%?80.12%, respectively. ?The N release amount was maximum in the green manure nutrients in first 7 weeks. ?The rate of nutrient release and organic matter decomposition of perennial ryegrass was slower the other green manure, and that of common vetch was slower the other green manure from 3 to 7 week. ?C/N ratio of green manure showed increasing tendency after ploughed. The earliest time of C/N ratio of green manure reached 24:1 was seventh week after ploughed. Therefore, plowing green manure 15-20d before flue-cured tobacco transplanting, transplanting tobacco seedlings was better after the soil properties to be alleviated.(2) Dynamics of the decomposition rate and nutrient release for corn stalk with different maturing agentThe dynamics of nutrient release and organic matter decomposition of corn stalk by using different decomposition maturing agent were studied. Results showed that ? decomposition characteristics of corn stalk manifested to three stages:the period of fast decaying at the beginninglO days after returned to the field,10 to 50 days was the period of middle speed decaying,50 days to the end of sampling was slowly decaying phase. ?The nutrition releasing of organic C?N?P?K to 100d were 55.64%?61.69%.54.21%?61.54%. 85.96%?89.82%?93.02%?95.81%.?The sequence of nutrients release rates of corn stalk was K>P>C>N.?Corn stalk with different decomposition maturing agent, with an adaptation period of 5-7d, the decomposing speed of corn stalk did not accelerated at the early application; ? Decomposition maturing agent can accelerate nutrition releasing of organic C?N and P of corn stalk.? Conclusion demonstrated that zymogeneous bacteria of organic waste was more appropriate to accelerate decomposition of corn stalk.(3) Effects of returning field of stalk and green manure on soil physico-chemical properties and yield and quality of flue-cured tobacco of XiangxiThe field experiment was carried out to study the effects of green manure and stalk and decomposition maturing agent on soil properties and yield and quality of flue-cured tobacco. Results showed that ? teturning field of stalk and green manure can improve the soil physical properties to some extent.? Returning field of stalk and green manure can increase the content of Soil Organic Matter, nitrogen, available phosphorus and available potassium, the treatment of green manure+corn stalk+decomposition maturing agent was the best.? Agronomic characters, chlorophyll and leaf area index of stalk and stalk with decomposition maturing agent at rosetle stage were better than green manure and CK, after that, the treatmeats of green manure were better than stalk and stalk with decomposition maturing agent and CK.?The tobacco physical characteristic of green manure+corn stalk+decomposition maturing agent was better.?The chemical composition of stalk and green manure returned to field had the better coordination. ?The economic characters of green manure+corn stalk+decomposition maturing agent was the best. ?Green manure+ corn stalk+decomposition maturing agent can be extended to improve the soil characters and quality and benefits of tobacco. |
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