辽西北旱地土壤水分调控

辽宁省西北部地区48 a的降雨量与蒸发量频率分析结果表明，降雨与蒸发高峰出现的时间差是产生春旱的重要原因，气候的干湿程度可用湿润系数0.33这个尺度来衡量，辽西地区48 a间冬春两季的湿润系数均低于0.33，夏季的湿润系数绝大多数高于0.33，在秋季的湿润系数接近0.33。采取秋季覆膜、顶凌覆膜和膜上留茬等保墒措施能够将秋季降水保存在土壤中，为第2年春播提供充足的土壤水分。在遭遇严重夏季干旱的情况下，玉米收获期秋季覆膜处理的小区5-15 cm的土壤含水量仍比顶凌覆膜和空白小区高出3个百分点。这说明秋季覆膜在干旱的情况下能够有效地保蓄土壤水分，且能持续较长的时间。 处理间玉米单穗籽实干重之差异达到了显著水平。

The Rain-resource Characteristics and Dryland Soil Moisture Control in Northernwest Liaoning Province

The rainfall and evaporation analysis result for 48 years in northernwest of Liaoning showed that the fastigium difference between rainfall and evaporation is one of the important reasons of drought occurring in spring. The drought degree can be scaled by means of using humidity coefficient (0.33). In this region the humidity coefficient is under 0.33 during winter and spring, But the humidity coefficient is close to 0.33 after harvest. The control measures with covering the plastic film and remaining stubble after harvest can store the rainwater in soil in autumn. The practice with covering film before spring also can be adopted. These measures can hold the rainfall in the soil and provide enough moisture for seeding in follwing spring. In the case of encountering severe drought, the soil moisture with covering the plastic film in autumn increased 3 percent compared to covering plastic film in spring and control. The dry mass of seeds different between covering practices is notable.