云南省典型县域烟田土壤肥力演变及综合评价

Changes of Soil Fertility and Comprehensive Evaluation for Tobacco Fields in Typical Counties of Yunnan Province

通过数据收集和野外采样,分析了宾川县1982年、2012年、2018年、2022年4个时期烟田耕层土壤pH和养分含量变化,并运用土壤综合评价法和克里格插值定量评价了土壤综合肥力指数(IFI)及其时空变异特征。结果表明:近40年(1982—2022年)来,宾川县烟田土壤pH(7.13~6.23)和有机质含量(35.30~27.71 g/kg)呈下降趋势,有效磷(12.11~50.71 mg/kg)和速效钾含量(158.66~321.03 mg/kg)呈上升趋势,碱解氮含量(119.03~117.00 mg/kg)无显著变化。IFI(0.49~0.62)呈上升趋势,均值由1982年的0.49()Ⅲ增加至2022年的0.62()Ⅱ,其中平川镇、拉乌乡、州城镇及宾居镇IFI增加幅度最大,当前高肥力区域主要分布于县东北部和南部,低肥力区域分布于西北部。此外,主成分分析表明影响烟田土壤肥力的主要内在因素由有机质变为速效钾。经过40年耕种管理,宾川县烟田肥力自西向东、自北向南逐渐增加,但养分指标非均衡性和肥力空间不均匀性增加,应稳定氮肥钾肥,减少磷肥施用。

Through data collection and field sampling,the changes of topsoil nutrient contents in 1982,2012,2018 and 2022 in tobacco fields in Binchuan County of Yunnan Province were analyzed,and soil integrated fertility index(IFI)and its spatial and temporal variation were quantitatively evaluated by using soil comprehensive evaluation method and Kriging interpolation.The results showed that in the past 40 years,soil pH(7.13–6.23)and organic matter content(35.30–27.71 g/kg)showed a decreasing trend,while the contents of Olsen-P(12.11–50.71 mg/kg)and available K(158.66–321.03 mg/kg)showed an increasing trend.No significant changes were found in alkali-hydrolyzale N content(119.03–117.00 mg/kg).Soil IFI(0.49–0.62)showed an increasing trend,with the average value increasing from 0.49(Ⅲlevel)in 1982 to 0.62(level)in 2022,with the largest increase appeared inⅡPingchuan,Lawu,Zhoucheng and Binju towns.Current high fertility areas were mainly distributed in the north-east and south,while low fertility areas in the north-west.In addition,principal component analysis showed that the main internal factors affecting soil fertility changed from organic matter to available K.After 40 years of cultivation and management,soil fertility gradually increased from west to east and from north to south,but the non-equilibrium of nutrient indicators and spatial heterogeneity of soil fertility increased,and nitrogen and potassium fertilizers should be stabilized while phosphorus fertilizers should be reduced.