重庆市涪陵区植烟土壤养分的适宜性评价及变异分析分的适宜性评价及变异分析

为明确土壤养分状况及变异特征，本研究以2012年和2017年涪陵区烟田土壤样品为研究对象，采模糊数学原理对土壤养分适宜性进行综合评价，运用t检验和多重比较方法分析了各肥力指标的变异情况。结果表明：研究区56.25%的土壤pH适宜，变幅在4.41～8.12之间；有机质含量变幅为7.62～39.99 g/kg，中等水平土壤占71.88%；全氮及速效氮、磷含量偏高，钾含量丰富。适宜性评价显示，2017年研究区植烟土壤适宜指数均值为0.6，变异系数为26.17%；适宜性指数分级表明，II级以上的植烟土壤占46.88%；与2012年相比，土壤pH、有机质、全氮、碱解氮、有效磷和速效钾分别增加了0.54、1.69 g/kg、0.58 g/kg、24.63 mg/kg、17.2 mg/kg和66.6 mg/kg。结果说明，研究区土壤酸化趋势有所减缓，氮、磷、钾及有机质等含量有逐渐增加趋势，因此，生产上要持续进行土壤改良，严格控制氮肥投入量，提升磷钾肥的有效性。

Assessment of Feasibility and Variation Analysis of Nutrient Contents in Tobacco-growing Soil in Fuling County, Chongqing

To analyze the status and changes of soil nutrients, 81 and 96 tobacco-growing topsoil samples in Fuing county were collected in 2012 and 2017, respectively. Soil feasibility index (SFI) and nutrients variation characteristics were evaluated and analyzed based on fuzzy mathematical theory, t-test and multiple comparison. Results showed that soil pH was ranged from 4.41 to 8.12, SOM ranged from 7.62 to 39.99 g/kg, and the middle suitability proportion was 71.88% of the total samples; soil total N and mainly available nutrients were over high; In 2017 the average of SFI of tobacco-growing soil was 0.6, the coefficient of variation was 26.17%, and the fertility was evenly distributed and the spatial variation was small, the proportion of SFI above the II grade was 46.88%; Compared to 2012, soil pH was increased by 0.54, the contents of organic matter, total N, available N, available P and available K increased by 1.69 g/kg, 0.58 g/kg, 24.63 mg/kg, 17.2 mg/kg and 66.6 mg/kg in 2017, respectively. These results suggest that soil acidification has been alleviated, the contents of nitrogen, phosphorus, potassium and organic matter have gradually increased. Therefore, soil improvement need to be continued, meanwhile nitrogen application should be strictly controlled and the effectiveness of phosphate fertilizer should be enhanced in tobacco production.