曲靖植烟土壤pH和主要养分空间变异特征及其影响因素

2017—2020年用GPS定位采集云南省曲靖市9个县区核心烟田耕层（0~20 cm）土壤样品6 685个，测定pH、有机质、水解性氮、有效磷和速效钾，运用地统计学和地理信息系统（GIS）分析上述指标的空间分布特征及其变异主控因素。结果表明：土壤pH、有机质、水解性氮、有效磷和速效钾变幅分别介于4.16~8.50、2.23~99.93 g/kg、14.88~393.36 mg/kg、2.45~142.78 mg/kg和19.65~991.33 mg/kg，均值分别为6.30、32.83 g/kg、125.42 mg/kg、29.92 mg/kg和270.38 mg/kg，变异系数分别为11.59%、33.54%、29.93%、64.54%和35.18%，均为中等程度变异。pH集中在微酸至中性，较适宜烤烟种植，有机质、有效磷和速效钾含量集中在中等至极高等级，共占研究区总面积的70%以上。半方差分析表明，土壤pH空间自相关性较强，变异受自然因素（土壤类型、质地和降雨）的主导；有机质、水解性氮和速效钾空间自相关性中等，变异受自然和人为因素（施肥）共同影响；有效磷的空间自相关性很弱，人为因素是造成其空间差异的主控因素。克里格空间插值结果揭示土壤pH空间连续性好，整体呈聚集分布，强酸和极强酸土壤主要分布在马龙、宣威和会泽；有机质、水解性氮、有效磷、速效钾呈不规则的块状分布，随机性较强，其中有机质、水解性氮、速效钾的高值区主要在富源、罗平，有效磷较高的区域集中在陆良、罗平。

Spatial Regional Variability Characteristics and Influential Factors of pH and Main Nutrient Contents in Tobacco-growing Soils in Qujing

From 2017 to 2020, a total of 6 685 soil samples were collected from the plough layers (0-20 cm) of core tobacco fields in nine tobacco-growing counties in Qujing, Yunnan Province, and then pH, organic matter, hydrolytic nitrogen, available phosphorus and rapidly available potassium of the soil samples were measured. By GPS positioning, geostatistics and geographic information system (GIS) were used to investigate the status, regional variation characteristics and spatial distribution of the above soil fertility indexes. Correlation analysis and variance analysis were used to assess the effects of major factors (soil type, soil texture, climate and fertilization) on soil fertility indexes. The results showed that:soil pH ranged from 4.16 to 8.50, organic matter from 2.23 to 99.93 g/kg, hydrolytic nitrogen from 14.88 to 393.36 mg/kg, available phosphorus from 2.45 to 142.78 mg/kg, and rapidly available potassium from 19.65 to 991.33 mg/kg, with mean values of 6.30, 32.83 g/kg, 125.42 mg/kg, 29.92 mg/kg, and 270.38 mg/kg, respectively. The coefficients of variation of the above indexes were 11.59%, 33.54%, 29.93%, 64.54% and 35.18%, respectively, showing moderate spatial variation. Soil pH ranged from slightly acid to neutral, which was more suitable for growing flue-cured tobacco. The contents of organic matter, available phosphorus and rapidly available potassium concentrated in the medium to the very high levels, accounting for more than 70% of the total area of the study area. The results of semi-variance analysis showed that the spatial autocorrelation of soil pH was strong, and the variation was dominated by natural factors (soil type, texture and precipitation). The spatial autocorrelation of soil organic matter, hydrolytic nitrogen and rapidly available potassium were moderate, and their variations were affected by both natural and anthropic factors (fertilization). The spatial autocorrelation of soil available P was weak, and anthropic activities were main controlling factors that caused the spatial difference. The results of ordinary kriging interpolation revealed that spatial continuity of soil pH was good, and the overall distribution was aggregated. The strong acid and very strong acid soils were mainly distributed in Malong, Xuanwei and Huize. The distribution of organic matter, hydrolytic N, available P and rapidly available K were irregular block with strong randomness. The high value areas of organic matter, hydrolytic N and rapidly available K were mainly in Fuyuan and Luoping, while the high value areas of available P were concentrated in Luliang and Luoping.