辽西地区春播期土壤湿度变化特征及气象影响因子分析

利用1981—2011年辽西地区土壤相对湿度、降水和气温资料，对该区土壤湿度和降水变化特征及二者关系进行分析。结果表明：土壤湿度具有明显干化趋势，同期降水不是唯一影响因子；春播期土壤湿度与前秋降水正相关，深层相关系数为0.69，与底墒显著正相关，相关系数最高可达0.84，如此显著的正相关是由于北方特有的封冻雨，秋季降水封冻在土壤里，到第二年春季，气温升高，解冻返浆，土壤变得湿润；5月土壤湿度与同期降水呈正相关，浅层相关系数为0.67，与气温呈负相关，深层相关系数为-0.58。

Analysis on soil moisture variation and its meteorological influencing factors at spring sowing period in western Liaoning Province

The variation characteristics of soil moisture and precipitation and their relationship in western Liaoning Province were discussed, using the data of soil moisture, precipitation and temperature from 1981 to 2011. The results showed that the soil moisture showed a remarkable desiccation trend and the precipitation in the same period was not the only influencing factor. There was a positive correlation between soil moisture at spring sowing period and precipitation of last autumn, and the correlation coefficient was 0.69 in deep layer; there was a significant positive correlation between soil moisture at spring sowing period and soil moisture before freezing, and the correlation coefficient was 0.84 at most. Such a positive correlation was due to the freezing rain that was special in northern China. The autumn rainwater could be frozen in soil in winter and be thawed in the following spring, making the soil to become moist. Soil moisture in May showed a positive correlation with precipitation in the same period, and the correlation coefficient was 0.67 in shallow layer; however, it showed a negative correlation with temperature, and the correlation coefficient was -0.58 in deep layer.