季节性冻土的分布与变化特征及对多样性农区农业生产的影响

DISTRIBUTION AND CHANGE CHARACTERISTICS OF SEASONAL FROZEN SOIL AND ITS INFLUENCE ON AGRICULTURAL PRODUCTION IN DIVERSE AGRICULTURAL AREAS

关键词:  季节性冻土  变化特征  不同地形  多样性农区  农业生产影响

Key words:  seasonal frozen soil  variation characteristics  different terrain  diversity farming area  impact of agricultural production

摘要:

目的 研究季节性冻土的分布与变化对多样性农区农业生产的影响，对于合理利用气候资源，指导当地农业生产具有重要的意义。方法 文章以临汾市为例，选用1960—2019年临汾市17个观测站逐日的冻土深度、温度、地温、降水量和蒸发量等资料数据，采用克里金空间插值法分析研究区冻土的空间分布，并运用M-K检验、一元线性回归、相关分析等方法分析研究区不同海拔高度季节性冻土的变化趋势及影响因素。结果 （1）临汾市季节性冻土深度山区大于盆地，北部大于南部，冻土深度与海拔高度正相关显著，相关系数为0.712（P<0.01）具有明显的垂直分布特征。（2）近年来最大冻土深度呈明显下降趋势，变化倾向率平均为-2.304cm/10年，高海拔地区变化趋势尤为显著，1982年冻土深度发生突变，突变后从一个相对偏深期跃变为相对较浅期。（3）冻土始冻日山区早于平川，北部早于南部，解冻日刚好相反，冻土持续期平均相差1个月左右；多年来临汾市土壤表面始冻日推迟，解冻日提前，冻土期明显减少，平均变化率分别为2.088d/10年、1.762d/10年和4.069d/10年，低海拔地区变化趋势更为明显。（4）相关分析表明，冻土深度受冬季地面最低气温影响极显著，其中1月的地面最低气温升高对冻土深度变化起到主要的促进作用，这种影响在高海拔地区更为明显；春、秋两季的地面最低气温升高，使研究区始冻日推迟，解冻日提前，相关系数分别为-0.741、-0.408（P<0.01），冻土期明显缩短，蒸发量的相对减少对冻土期和冻土深度变化起到一定抑制作用，降水量对冻土期和冻土深度影响甚微。结论 临汾市冻土期缩短，冻土深度变浅，使越冬农作物干旱加剧，病虫害发生几率增加，同时增加了植物安全越冬系数，使作物生长季延长，对农业增产起到一定作用。

Abstract:

Studying the influence of seasonal frozen soil distribution and change on agricultural production in diverse agricultural areas is of great significance for rational utilization of climate resources and guiding local agricultural production. Based on the daily meteorological data of frozen soil depth, temperature, ground temperature, precipitation and evaporation from 17 observation stations in Linfen City from 1960 to 2019, the spatial distribution of frozen soil in the study area was analyzed by Kriging spatial interpolation method, and the changing trend and influencing factors of seasonal frozen soil at different altitudes were studied by M-K test, linear regression and correlation analysis. The results were listed as followed.（1）The depth of seasonal frozen soil in Linfen city is larger than that in the basin, and greater in the north than in the south. There was a significant positive correlation between the depth of frozen soil and altitude(with R 0.712), which has obvious vertical distribution characteristics. （2）In recent years, the frozen soil depth in Linfen city decreased obviously at an average rate of 2.304cm/10 year, and the change trend was more obvious in high altitude areas. In 1982, the frozen soil depth suddenly changed from a relatively deep period to a relatively shallow period. （3）The freezing day of frozen soil was earlier in mountainous area than Pingchuan, and earlier in north than in south. The thawing day was just the opposite, and the average difference of frozen soil duration was about one month. Over the years, the freezing date of soil surface in Linfen city has been delayed, the thawing date has been advanced, and the frozen soil period has been shortened, with changing rate 2.088, -1.762 and 4.069d/10 year, respectively.The freezing date has been delayed and the thawing date had been advanced in Linfen Basin and Lvliang Mountain Area, but the change trend in Anze County in the east was not obvious, and its change had obvious regional characteristics. （4）Correlation analysis showed that the frozen soil depth was significantly affected by the minimum ground temperature in winter, and the increase of the minimum ground temperature in January played a major role in promoting the change of frozen soil depth. The lowest ground temperature rose in spring and autumn, which delayed the first freezing day, advanced the thawing day and shortens the frozen soil time obviously(with R -0.741 and -0.408, respectively). The relative decrease of evaporation could restrain the change of frozen soil period and depth, but the change trend of rainfall was not obvious, and it had little effect on the change of frozen soil. To summary, the frozen soil period is shortened and the frozen soil depth is shallower in Linfen city, which increases the safe overwintering coefficient of plants, prolongs the growing season of crops and plays a certain role in increasing agricultural production and income.