农田生态系统不同土地利用方式与管理措施对土壤质量的影响

于2005年在北京市延怀盆地选择农田生态系统中的玉米地、大豆地两种传统土地利用方式，以及近10～20 年由传统农业用地转化而来的蔬菜和果园用地，研究农田生态系统不同土地利用方式与管理措施对土壤质量的影响.结果表明，菜地、果园和高投入玉米地土壤总有机碳(SOC)、全氮(TN)和全磷(TP)含量明显高于中、低投入玉米地和大豆地土壤.在各种土地利用类型中，SOC、TN和TP的变化范围分别为7.67～10.00 g·kg^-1、0.75～1.12 g·kg^-1和0.63～1.00 g·kg^-1；菜地土壤有效磷(AP)含量和电导率(EC)显著高于其他土壤，不同农田生态系统土壤物理性状差异不明显.果园和菜地土壤质量指数分别为0.525和0.503，高于传统农田玉米和大豆土壤(0.417～0.494).菜地土壤的养分有效性最高，水分有效性和根系适宜性低于果园土壤，应注意菜地非点源污染的潜在风险.在传统农业用地中应采取培肥地力等方式提高土壤质量.

Effects of land use and management practice on farmland soil quality in Yanhuai basin of Beijing

In April 2005, a total of 41 soil samples were collected from the sandy loam soil (Ustochrepts) under orchard, vegetable, corn (Zea maize L. ) and soybean (Glycine max L. ) in Yanhuai basin of Beijing, and their physical, chemical, and biological properties were analyzed. The results showed that the contents of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) in vegetable field, orchard field, and high-input corn field were obviously higher than those in soybean field and mid- and low-input corn fields. In these fields, SOC content varied from 7. 67 to 10. 00 g x kg(-1), TN content varied from 0. 75 to 1. 12 g x kg(-1) , and TP content varied from 0. 63 to 1. 00 g x kg(-1). Soil available phosphorus (AP) content and electric conductance (EC) were significantly higher in vegetable field than in other fields, while no significant differences in soil physical properties were observed among the four land use types. The soil quality index of orchard and vegetable fields was 0. 525 and 0. 503, respectively, being higher than those of corn and soybean fields (0. 417-0. 494). Vegetable field had the highest efficiency of soil nutrients, but non-point source pollution risk should be minded. For soybean field and mid- and low-input corn fields, intensive management should be practiced to improve their soil quality.