| Vicia villosa Roth var is one of the main green manures in tobacco field in Hubei Province. The effect on tobacco development and production quanlity, conducting by different manure application amounts and periods, and nutrience release tendency of green manure was investigated in this study using 2 years field positioning and buring nylon bags experiment, for the purpose of providing theory basis for effective use of green manure in the area of tobacco region, the southwest of Hubei province. The main results were showed as follows:1. With the buried nylon bags method a field experiment was carried out in tobacco fields to study dynamics of nutrient release and decomposing rates of Vicia villosa Roth var. as green manure. Results show that there was no significant influence on organic matter decomposition and nutrient release dynamics of turn Vicia villosa Roth var. in tobacco fields whether it planted flue-cured tobacco or not. The decomposition rate of organic matter in Vicia villosa Roth var. may be divided into three stages on tobacco fields. The decomposition rate of the first two weeks was the largest one, and then from 3 to 9 weeks, the rate became slower after the ninth week. The decomposition contents accounted for 27.34%～33.16%,2.52%～4.61% and 1.01%～1.74% separately in these three stages per week. The relationship between the release of C,N and K in Vicia villosa Roth var. and turning time may be fitted by exponential equation, the release rate of the first 1-2 weeks was the fastest one, and then it would rapidly decline until stable. The release of N accounted for 78.61%～92.27% of the total release in the whole growth period of the plant in the first 5 weeks, so it didn't lead to the problem that supplied excessive nitrogen might postpone the mature of tobacco. However, the release rate of P was relatively stable in Vicia villosa Roth var., and didn't have obvious stages, the relationship between the release of P and turning time may be fitted by linear equation. The release rates of C,N,K,P in Vicia villosa Roth var. were 68.76%～84.95%,69.57%～84.51%,97.09%～98.95%, 41.26%～74.10% respectively during decomposition of the whole growth period of the plant. When we turned under Vicia villosa Roth var. as green manure in tobacco fields, they should be turned under before tobacco transplanted, and reduced the amount of fertilizer properly. 2. A 2 years field experiment was conducted to study the the effect on tobacco development and production quanlity, also about nutrient absorption, researching by different manure application amounts and periods in Enshi city, Hubei province. The results showed that, the deal with different green manure application amounts, comparing with CK, the tobacco height, leaf amounts, stem width, and the biggest leaf area were higher, but there was no significant difference compared with common fertility usage. The result showed, on the foundation of turning over green manure, there was no impact by reducing fertility amount compared with common fertility usage, but slightly increasing leaf area. Tobacco production also couldn't be reduced, which was supported by the dry weight testing of tobacco roots, stems and leaves. With the method of decreasing 30% fertility usage, turning over green manure by 15000 kg/hm2～22500 kg/hm2 could increase tobacco quality. In 2009, the quality result of 15000 kg/hm2 was the best, increasing 1.96% compared with 100% fertility usage, and the proportion of middle-upper leaves was higher than several dealings of 85% fertility usage. By 2010, the result of 22500 kg/hm2 was the highest, increasing 12.53% compared with 85% fertility usage, and the proportion of middle-upper leaves was higher than several dealings of that. On the condition of decreasing fertility usage, turning over green manure can augmen amounts of nitrogen and potassium in tobacco roots, stems and leaves in early growth, and in later growth, decreasing nitrogen amounts in roots and leaves, increasing potassium amounts in leaves. The best result was by reducing 30% fertility usage and turning over green manure of 15000 kg/hm2～22500 kg/hm2. Considering overall analysis, the adoption method was by reducing 30% common fertility usage and turning over green manure of 15000 kg/hm2～22500 kg/hm2 in Enshi city, Hubei province.3. A 2 years field experiment was conducted to study the the effect on tobacco development and production quanlity, also about nutrient absorption, researching by different manure application amounts and periods in Enshi city, Hubei province. The result showed that there was no difference in tobacco rapid growth and maturity periods by turning over green manure ahead, but by 14 to 29 days ahead could increase the biggest leaf area and leaf quality, and tobacco yield by 14 to 19 days ahead, which were provided by tobacco dry weights of roots, stems, and leaves. In 2009, turning over green manure ahead of 29 days obtained the hightest output, increasing 8.91% compared with common fertility use, and the proportion of middle-upper leaves was higher than 85% fertility usage. In 2010, Ahead of 14 days had the hightest output, increasing 15.99% compared with common fertility use, and the proportion of middle-upper leaves was higher than 85% fertility usage too. Turning over green manure ahead of 14 days or 29 days could augmen amounts of nitrogen and potassium in tobacco roots, stems and leaves in early growth, and in later growth, decreasing nitrogen amounts in roots and leaves, increasing potassium amounts in leaves. Through 2 years continual experiments, it was found that the best turning over period trend ahead and 14 to 29 days ahead was the best. |
