了解土壤湿度的时空变化特征与规律,对充分利用土壤水分资源及应对气候变化有重要意义。基于三江平原23个农业气象站1982—2017年土壤湿度、同期气温、降水等数据,采用统计分析、M-K突变检验等方法,分析了0—50 cm土壤湿度的趋势变化特征及其与气温、降水气候因子的关系。结果 表明:(1)近37年来三江平原地中0—30 cm,40—50 cm土壤相对湿度呈显著降低趋势,并呈阶段性变化,突变年在1997年; 30—40 cm土壤相对湿度无显著变化; 各层土壤相对湿度垂直方向呈现中间层(30—40 cm)土壤相对湿度最大,上下层递减的趋势。土壤相对湿度的空间分布存在差异,土壤相对湿度由北到南、由东到西递减趋势。(2)三江平原气温、降水量对各层土壤相对湿度影响程度不同。0—20 cm土壤相对湿度主要受4—9月生长季气温、降水量的协同作用影响,20—30 cm和40—50 cm土壤相对湿度分别受4—9月生长季的气温和降水作用的影响; 而30—40 cm土壤相对湿度受气温和降水作用的影响不大。总之近37年来三江平原土壤相对湿度的变化存有差异,1982—1996年、1997—2013年、2014年后各层土壤相对湿度分别处于相对较高(偏湿)、较低(正常)、较高(偏湿)阶段。4—9月生长季的气温和降水是影响三江平原土壤相对湿度变化的主要气象因子。
It is of great significance to make full use of soil moisture resources and cope with climate change to understand the spatiotemporal variation characteristics and rules of soil moisture. Based on the data of soil moisture, temperature and precipitation of 23 agricultural weather stations in Sanjiang Plain during the period from 1982 to 2017, the trend variation characteristics of soil moisture in the land(0—50 cm)and its relationship with temperature and precipitation climate factors were analyzed by using statistical analysis, M-K mutation test and other methods. The results showed that:(1)in the past 37 years, the relative humidity of 0—30 cm and 40—50 cm soil in Sanjiang Plain presented a significant trend of decrease and stage change, and the mutation occurred in the year of 1997, but there was no significant change in the layer of 30—40 cm; in the vertical direction, the soil relative humidity in the middle layer(30—40 cm)was the largest, and soil relative humidity in the upper and lower layers presented the decreasing trend; the spatial distribution of soil relative humidity was different, and the soil relative humidity decreased from north to south and from east to west;(2)the degree of influence of temperature and precipitation on soil relative humidity in Sanjiang Plain was different; the relative humidity of 0—20 cm soil in the shallow layer was mainly affected by temperature and precipitation from April to September growing season, while the relative humidity of layer(20—30 cm)and the layer(40—50 cm)were affected by temperature and precipitation, respectively, in the growing season from April to September; however, the relative humidity of the layer(30—40 cm)was not affected by air and precipitation. All in all, there are differences in soil relative humidity in Sanjiang Plain in recent 37 years. The relative humidity of each layer was in relatively high(wet), lower(normal)and higher(wet)stages after 1982—1996, 1997—2013 and 2014, respectively. The temperature and precipitation in the growing season from April to September are the main meteorological factors affecting the soil relative humidity in Sanjiang Plain.
