Tobacco-planted Soil Boron Nutrient And Effect Of Boron Fertilization In Chongqing

China is one of the counties of the biggest tobacco production and consumption. Tobacco production takes up a very important status in National economic, while the lower tobacco quality is the main reason of the low rate of export and the low benefit. As one of the main tobacco-planted regions, Chongqing has an area of 47,000 hm² planting tobacco soil. Tobacco industry is not only the leading industry of breaking away from poverty but also the primary resource of finance and revenue in tobacco-planted regions in Chongqing. Recently, a lot of researches are studied about the proper from of nitrogen and potassium and the proper quantity and proportion of nitrogen, phosphorus and potassium, and a standard technique of tobacco planting and fertilization were formed. But the research on tobacco microelements nutrition was few, especially boron nutrition. In this paper, the contents of boron in tobacco-planting soils, as well as the effect of different BO₃^3- concentration and different boron application on the growth, nutrients absorbed, nutrients accumulation, economic character and quality of tobacco were studied by investigation, solution experiments, field experiments and laboratory analysis in Chongqing. The purposes of this study were to understand the status of boron content in tobacco-planting soil, in order to provide detailed information for improving the quality of flue-cured tobacco leaves in Chongqing. The main results were as follows:1.Available boron content of tobacco-planted soil in Chongqing cityThe content of available boron in various tobacco-planting soils was low, which average content was 0.37mg·kg^-1 with the range of 0.07 to 1.99 mg·kg^-1 in Chongqing. The available boron contents in 32.35% of the soil samples were lower than 0.25mg·kg^-1 which was very unfit for tobacco planting. The available boron contents in 24.26% of the soils were more than 0.5mg·kg^-1 and were fit for tobacco planting. In the tobacco planting regions in Chongqing, the average available boron content that was 0.21 mg·kg^-1 and 0.24 mg·kg^-1 in soil was lower in Wulong and Pengshui county, the boron deficiency soils were in the proportion...