汉中盆地耕地土壤有机质的空间特征
Spatial characteristics of soil organic matter in cultivated land in Hanzhong Basin

【目的】研究汉中盆地耕地土壤有机质的空间自相关性、空间变异特征以及空间分布规律。【方法】根据地貌特征，以位于汉中盆地中部的平坝区作为研究区，于2010－2011年共采集土样3 568个，测定土样有机质含量，对获得的有机质含量原始数据进行处理后，综合运用传统统计、地统计和地理信息系统技术，研究汉中盆地耕地土壤有机质空间特征。【结果】研究区耕地土壤有机质含量为7.20～38.00 g/kg，平均值为21.53 g/kg，变异系数为24.48%，属中等强度变异；研究区耕地土壤有机质为空间聚集式分布，呈显著的正空间自相关，空间自相关尺度为 4.70 km；耕地土壤有机质含量的块金系数为0.55，表现为中等强度空间相关性；研究区61.13%的耕地土壤有机质含量较高（≥20～＜30 g/kg），整体分布格局为西高东低、南高北低，其中自东北向西南方向土壤有机质含量呈增加趋势。【结论】研究区大部分耕地土壤有机质含量较高，能够满足农作物生长的需要。
【Objective】This study analyzed the spatial autocorrelation,variability and distribution of soil organic matter (SOM) in Hanzhong Basin,Shaanxi Province.【Method】The plain area in Hanzhong Basin was chosen as the study area according to the geomorphological characteristics.Based on SOM contents of 3 568 soil samples collected in Hanzhong Basin from 2010 to 2011,traditional statistics,geostatistics and geographical information system technology were used to analyze the spatial characteristics of SOM in cultivated land.【Result】SOM contents of soil samples in the study area ranged from 7.20 g/kg to 38.00 g/kg with the average of 21.53 g/kg and the variation coefficient of 24.48%, indicating moderate variability.The spatial autocorrelation of SOM content was positive and strong with the active range of 4.70 km.The nugget coefficient of SOM content was 0.55,indicating medium spatial correlation.61.13% of the study area had high contents of SOM (≥20-<30 g/kg).Overall,SOM content was high in the west and south and low in the east and north.There was a significant variation trend from northeast to southwest.【Conclusion】SOM contents in most cultivated land were high and enough to supply the needs of crops