土壤有机质空间变异与农用地自然质量关系研究

该文以广州市花都区赤坭镇为试验区，根据典型农用地类型的土壤采样基于Cokriging方法进行土壤有机质精确插值与空间变异分析，并将结果与农用地分等成果进行相关分析。结果表明，以土壤有机质和农用地类型为协因子的球状模型Cokriging总体插值精度最高，试验区内土壤有机质分布格局是四周丘陵和水库区含量较低，巴江河两岸的平原地区、西南角的山前冲积平原含量较高，这也是灌溉水田密集的区域；试验区内土壤有机质含量菜地分布比较均匀、空间相关性很强，而水浇地分布差异较大、空间变异性较高；土壤有机质分布在南北、东北-西南两个方向相关性较强具有各向同性特征，在东南-西北、东西方向具有各向异性特征，受到随机因素的影响变异性较大。土壤有机质Cokriging插值结果与试验区内农用地自然质量等指数的相关性很显著，菜地与农用地自然质量等指数相关性最强，灌溉水田其次，旱地最差。

Spatial variability of soil organic matter and relation with natural quality of farm land

The present study researches exact interpolation and variability character of soil organic matter by Cokriging method which uses soil sample data in typical types of farm. Taking Chini town of Huadu County, Guangzhou City as an example, this study examines the quantitative relationship between soil organic matter and natural quality of farm land. The results show that the precision of Cokriging interpolation with soil organic matter and farm type variable by spherical model is the highest. In research areas, it is a distribution pattern of soil organic matter that low levels are in the surrounding hills and reservoirs, and high levels are in plains nearby the two sides of Bajiang River and Piedmont alluvial plains of south-west hills. The areas with high levels are paddy-intensive. In research areas the soil organic matter content in vegetable fields is well-distributed with strong spatial correlation and its distribution in irrigated fields is quite different with large spatial variability. Soil organic matter is isotropous in north-south and northeast-southwest direction with stronger spatial correlation, and is anisotropic in the southeast-northwest and east-west direction with larger spatial variability. There is a very significant relevance with interpolation result of soil organic matter and grade index of natural quality of farm land. Correlation of natural quality index of vegetable farm with that of farm land is most significant, then the paddy field, last the dry land.