长期地膜覆盖对棕壤水分含量和储量动态变化的影响

Effect of Long-term Covering with Plastic Film on Dynamic Changes of Soil Water in Brown Earth

棕壤长期定位实验结果表明，长期地膜覆盖对土壤剖面内0～60cm的土壤水分动态变化有较大影响。从播种前期（4月20日）至大喇叭口期（6月30日）以及长粒期（8月15日）至作物收获后的结冰期（11月10日），在0～20cm和20-40cm这两个层次覆膜处理的土壤含水量基本上均高于裸地，而在40—60cm这个层次整个生长季覆膜处理的土壤含水量基本上均接近甚至低于裸地，同时长期的地膜覆盖保护了60-100cm的土壤水分。从整个生长季来看，0.40cm和40～100cm这两个层次土壤水储量均是覆膜高于裸地。因此地膜覆盖是干旱地区一种重要的保水措施。

This experiment was conducted on the loamy brown earth derived from loess-like parent materials at Shenyang Agricultural University during 1987 -2003. The main results showed that the effect of longterm covering with plastic fihn on dynamic changes of soil water in 0 -60cm layer was significant from April 20 to June 30 and August 30 to November 10. The average contents of soil water in 0 - 20cm and 20 -40cm of all covered treatments were higher than those of corresponding no covered treatments. But, the average contents of soil water in 40 -60cm of all covered Ireatments were close to those of corresponding no covered treatments and even lower. In addition longterm covering with plastic fihn stored more water in 60 - 100cm. Also, in the whole crop growing seasons, the average storage of soil water at 0 -40cm and 40 - 100era in all covered treatments was higher than all that of no covered treatments.