Comprehensive Evaluation Of Tobacco-growing Soil And Research Of Reduction Efficiency Of Nitrogen Fertilizer In Typical Area Of Yunnan

In order to study the characteristics of flue-cured tobacco soil in Luoping of Yunnan. In this experiment,339 soil samples were surveyed from 10 main tobacco-growing villages and towns of Luoping County and the soil resources were analyzed. Using GIS technology, fuzzy mathematics and principal components analysis, we also assessed the nutrient contents, soil fertility suitability and the change of soil nutrient and SFI. Effect of nitrogen fertilizer reduction on flue-cured tobacco growth and tobacco quality with straw returning was research. The main findings are as follows:The resources of soil agrotype in Luoping County mainly including red soil, yellow soil, a new soil, paddy soil and purple soil. The proportion of red soil and yellow soil were 50.45% and 27.43%, respectively. The planting tobacco soil are mainly distributed in the mountain, pingba, hills and river channel. Give priority to with the mountain,, accounting for 78.18%. The planting tobacco soil are mailly distributed in the elevation between 1322--2115m, with 1800～1950m proportion is the lagest, accounting for 37.76%.The pH, rapidly available P, rapidly available K, available Zn and available B content were at an appropriate level while organic matter, hydrolytic N, available Mg and water-soluble Cl- content were high. the integrated fertility index of most tobacco-growing area in Luoping was in better and medium level, the average SFI value was 0.7629 and soil fertility was in good comdition. The SFI did not differ significantly between agrotype and terrain, but highy significantly difference between towns and altitude. The order of usability among towns was Dashuijin>Banqiao>Jiulong>Luoxiong>Agang>Majie>Zhongshan >Jiujiwu>Laochang>Fule, among altitude was the medial altitude(1500-1800m) was high, while low altitude(< 1500 m) and high altitude (> 1800m) were slightly lower; From 2008 to 2014, the organic matter content reduced, while the pH value, content of hydrolytic N, rapidly available P, rapidly available K, available Zn, available Mg, available B, water-soluble Cl- and SFI value increased.Rape straw returned to increase the yield and quality of tobacco leaves. On the basis of reducing nitrogen straw returned was not significant effects on tobacco economic characters.The chemical component Usability Index of tobacco leaves was:N4>N3>N5>N2> CK>N1>NO. Reduced by 20%-40% nitrogen fertilizer can achieve the effect of lean production based on straw returned.