宜宾地区土壤养分空间变异及其丰缺状况分析

为探明宜宾地区主要土壤养分含量状况，基于野外采集的676份土壤样品，运用经典统计方法、地统计学方法和GIS技术分析了该区域8种土壤养分指标的空间变异特征及其丰缺状况。结果表明，宜宾地区土壤有机质、全氮、全钾和缓效钾含量适宜，碱解氮含量丰富，而速效钾、全磷和有效磷含量缺乏。各养分指标块金效应在44.02%~81.93%；其中有效磷和速效钾的空间自相关性较弱，主要受随机因素影响。空间分布上，有机质含量总体呈现东南高、中部和北部低；全氮和碱解氮含量由西北、东南向中部区域下降；全磷呈南高北低趋势，有效磷呈斑块状分布；缓效钾由中部向西北和东南部逐渐下降；速效钾表现为西高东低，全钾与之相反。本研究结果为宜宾地区烤烟平衡施肥及种植规划提供了理论依据。

Spatial Variability and the Status of Abundance or Deficiency of Soil Nutrients in Yibin City

In order to investigate the spatial distribution of main nutrients in tobacco planting soils, 676 soil samples were collected in Yibin City. The GIS technology was used in combination with classical statistics and geostatistics to analyze the spatial variation of 8 soil nutrients. The results indicated that the contents of soil organic matter (SOM), total nitrogen (TN), total potassium (TK), and slowly available potassium were all at appropriate levels, and alkali-hydrolyzed nitrogen (AN) reached a rich level while available potassium (AK), total phosphorus(TP) and available phosphorus (AP) were insufficient. The ratio of nugget to sill was between 44.02% and 81.93% for all the indexes selected. The ratio for AP and AK was substantially higher than that of the others, indicating a weaker spatial autocorrelation and the spatial variation of the two indexes was dominated by random factors. The spatial distribution pattern of SOM showed a trend with higher values in southeast and lower in central and north. The TN and AN contents declined from the northwest and southeast to the central area in this study. The TP content decreased from the south to north while the high AP value areas were mainly scattered plaques in the studied areas. Slowly available potassium showed a decreasing trend from the central to northwest and southeast, while AK had a higher content in west but lower in east, which is in contrast with TK. The results provide a theoretical basis for balanced fertilization and planting planning of tobacco planting areas in Yibin City.