广东耕地土壤有机质的变化趋势及其驱动力分析

Changes and Driving Forces of Farmland Organic Matter in Guangdong Province, China

利用广东省1984—2010年的土壤长期定位监测数据,对全省20多年来的耕地土壤有机质变化趋势进行了分析。结果表明:1984—2010年,全省耕层土壤有机质含量总体表现稳定,但近年来呈下降趋势,尤其是珠三角地区较为明显。全省不同区域的有机质含量差异显著,粤东地区偏低,平均含量比粤北低22%。不同土壤类型的耕地有机质变化趋势亦有差别,赤红壤和紫色土耕地的有机质含量偏低,分别只有13.0 g/kg和11.2 g/kg,占耕地面积比例最大的水稻土近5年来有机质含量下降了1.5 g/kg。对全省耕地有机质变化的驱动力分析表明,优质农田的流失、种植模式的变化是影响全省耕地有机质含量整体水平降低的原因之一。

The change of farmland organic matter was analyzed by using long-term monitoring data in Guangdong Province, South China. The results showed that farmland organic matter content in Guangdong Province did not change significantly from 1984 to 2010, but showed a decrease trend in last 5 years, especially for the farmland organic matter in the Pearl River Delta. There were significant differences in organic matter content between different regions： east Guangdong was 22% less than north Guangdong. Soil types affected the organic matter content. Organic matter content in farmland originated from Latosolic red soils and Purplish soils were lower, which were 13.0 g/kg and 11.2 g/kg respectively. The mean of organic matter content of paddy soil which was with the largest area decreased 1.5 g/kg in last 5 years. The decrease of farmland organic matter in Guangdong Province was mainly due to the loss of high-quality farmland and the change of planting model.