Suitability Evaluation and Influencing Factors of Soil Fertility in Tobacco Growing Areas of Huayuan County, Xiangxi Prefecture

Purpose In order to know the fertility level of tobacco planting soil in Huayuan County, some suggestions were put forward for scientific fertilization in Huayuan tobacco growing area.

Method 160 soil samples were collected from Huahuan County by adopting GPS technology, the nutrients content were tested. Suitability index of soil fertility (SFI) was calculated using fuzzy mathematics method on the foundation of GIS technology and statistics. The soil fertility suitability comprehensive evaluation of tobacco growth area and its influences was analyzed.

Result 1) The soil alkali solution nitrogen, exchangeable calcium and magnesium contents of Huahuan County tobacco growth area were appropriate, effective phosphorus and sulfur contents were extremely high, rapidly-available potassium content was rich, total nitrogen and organic matter contents on the high side, and the soil pH was low, the chloride ion content was very low. 2) The SFI of Huahuan County tobacco cultivating soil reached a mean value of 0.58, normal soil fertility conditions, the soil fertility suitability among townships showed up as Yaqiao>Daoer>Malichang>Yayou> Paibi > Changle>Huahuan >Pailiao > Buchou > Dongmaku > Jiwei. 3) Few area in Huahuan County, only 0.18%, manifested excellent SFI, fairly fine occupied 14.77%, middle level accounted for 30.62%, general area accounted for 44.52%, for poor area accounted for 9.91%. 4) The SFI of those whose preceding crop were tobacco and maize crop was significantly greater than that of rice crop. There were significant differences in nutrient content of tobacco planting soils in different ways. 5) The SFI of tobacco planting area decreased with the increase of altitude.

Conclusion The tobacco planting soil is suitable for tobacco production in Huayuan tobacco growing area. According to the characteristics of tobacco planting soil nutrient status and soil fertility of different regional towns, it is suggested to control the amount of nitrogen fertilizer, increase the utilization rate of phosphate fertilizer and use the chloride potassium fertilizer. For soil acidification townships, such as Paibi, Dongmaku and Huayuan Counties, it is suggested that lime, dolomite or other alkaline fertilizers be used for directional improvement of soil.