1983—2019年黑龙江省春季土壤湿度时空变化特征及影响因素

春季土壤湿度是影响东北粮食产量和品质的重要因素。在气候变暖的背景下,东北春季土壤湿度如何变化,鲜有研究。本文基于1983—2019年黑龙江省22个农业气象站的土壤湿度和气象观测资料,采用方差分析、突变分析及空间分析等方法,分析20世纪80年代以来黑龙江省春季土壤湿度的时空变化特征及其影响因素。结果表明：1983—2019年黑龙江省春季0~30 cm土壤湿度均值为88.22%,0~10 cm、10~20 cm、20~30 cm土层土壤湿度平均值分别为82.63%、89.66%、92.36%,土壤湿度随深度增加而增加,各层均未出现干旱状态。但各层土壤湿度均出现极显著下降趋势,21世纪最初10年较20世纪80年代各层土壤湿度下降6%~15%,在20世纪80年代末进入偏干期。黑龙江省春季土壤湿度呈现由东到西逐渐减小的趋势,32%左右的观测站点呈现显著下降趋势,主要集中在黑龙江省西部及东部地区。前秋季降水量、积雪期长度和积雪初日是影响各层及各月份土壤湿度最重要的因素,其对土壤湿度的影响能持续到5月份,并能影响到20~30 cm。积雪深度及积雪终日对4月份表层土壤湿度有重要影响。地表温度、日平均气温、日平均风速和降水量也是影响不同时期不同深度土壤湿度的关键因素。

Spatial and temporal variability of soil moisture in relation with meteorological factors in spring from 1983 to 2019 in Heilongjiang province

Soil moisture in spring is an important factor affecting grain yield and quality in Northeast China, which has been rarely studied in terms of variability of soil moisture during spring season in this region under the background of climate change. Soil and meteorological data of 22 agricultural meteorological stations from 1983 to 2019 in Heilongjiang province are used to examine the spatio-temporal variability of soil moisture in spring since the 1980s, by methods of classical statistics and geostatistics such as variance analysis, mutation analysis, and spatial analysis. The results show that the mean soil moisture (0-30 cm depth) is 88.22% in the study area in the spring of 1983-2019, and the mean values of soil moisture at depths of 10 cm, 20 cm, and 30 cm are 82.63%, 89.66%, and 92.36%, respectively, that is to say, soil moisture increases with depth. Soil moisture of each layer is not in status of drought, but shows decreasing trends. Compared with the 1980s, soil moisture of each layer decreased by 6%-15% in the 2010s, being in a dry stage since the 1980s. From east to west, soil moisture in spring presents a decreasing trend and it decreased significantly at about 32% of observation points, which are located mainly in the west and east of the province. The most important factors affecting the soil moisture in each layer and month are precipitation in the preceding autumn, snow accumulation period and beginning date of snow cover, which can affect soil moisture at 30 cm depth until May. Snow depth and ending date of snow cover have important effects on the surface soil moisture in April. Surface temperature, daily mean temperature, daily mean wind velocity and precipitation are also key factors influencing soil moisture at different depths in different periods.