The System Research Of Nutrient Status Of Tobacco-growing Soil In Sangzhi Village

This paper gradually analyses nutrient status, nutrient adsorption capacity and main limiting factors determination of seven tested tobacco-growing soil in Sangzhi County, which taking advantage of the analysis of soil nutrient status and adsorption experiment, biological pot experiment and field experiment of fertilizer, and to carry out field test to verify. So to ascertain the main limiting factors of tobacco-growing soil nutrient in Sangzhi County, and provide a scientific basis for local tobacco production and scientific fertilization that will promote the increasing both in production and quality of Flue-cured tobacco. The results are as follows:(1) With the analysis of soil nutrient status, the nutrient content of tobacco-growing soil in Sangzhi County is generally not high. N, P, S, Zn, Mg and Cu are lower than nutrient appropriate value, which may be the potential limiting factor of nutrient for growth of local Flue-cured tobacco. By the analysis of soil adsorption and biological pot experiment to identify, N is the first limiting factor and P, Mg are respectively the second and the third limiting factor of soil nutrient in tobacco-growing soil in Sangzhi County.(2) The limiting factors of nutrient and its abundance order is basically the same that be reflected by the biological pot experiment taking sorghum and Flue-cured tobacco as indicator plants. It shows that sorghum as the generic indicator plant could also be used in tobacco-growing soil. But the two indicator plants still exist certain differences due to the regulation of fertilizer of physiological requirement is different, so the selected indicator plants in the pot experiment are better to keep the same with the field planting crops.(3) In the field fertilizer efficiency test, applying4.6kg/hm2P,8.6kg/hm2Mg fertilizer based on the local custom fertilization is most conducive to the growth of Flue-cured tobacco. Under the tested field conditions, the effective nutrient of soil as N, P is high and the roots of Flue-cured tobacco are developed, its absorption on N, P is strongest, and tobacco growing is the most popular. After the harvest of Flue-cured tobacco in field, applying4.6kg/hm2P,8.6kg/hm2Mg fertilizer based on the custom fertilization, both the production and the quality of Flue-cured tobacco are the best. Comparing with the custom fertilization, the production of per mu of Flue-cured tobacco increase to44.9%, and the classy smoke proportion reached76.9%; only by the application of4.6kg/hm2P fertilizer based on the custom fertilization, the yield of tobacco increased by23.1%, the classy smoke accounted for70.5%; only by the application of8.6kg/hm2P fertilizer based on the custom fertilization, the yield of tobacco increased by13.2%.