气温变化对西峰黄土高原地温与梨树发育期的影响

Influence of air temperature change to ground temperature and pear tree development period at Xifeng of the Loess Plateau

用西北地区140站1961-2000年的气温资料和西峰黄土高原1971-2005年5,10,15,20cm地温和1984-2005年梨树发育期资料,分析了西北地区春季、夏季、秋季、冬季和年气温的变化事实,再用相关计算和典型年份对比,分析了地温的时间变化规律及其对梨树发育期的影响。结果表明,西北地区20世纪60年代冬季增温,其余降温,70年代均降温,80年代冬季增温,其余降温,90年代均增温,冬季的最明显。西峰10cm地温各季节呈持续升高的趋势,春季增温最明显为0.058℃/a,变幅也最大,冬季增温幅度次之为0.039℃/a,再是秋季为0.032℃/a,夏季增温幅度最小为0.029℃/a,上升趋势均通过0.05和0.01的信度检验。冬季、春季地温与梨树的各发育期均为负相关,即地温高,发育期早,地温低,发育期迟。冬季地温与梨树发育期相关最显著的是叶变始期和开花始期,相关系数为-0.41～-0.52,信度为0.05,春季地温与之相关最显著的是开花始期,相关系数为-0.68～-0.69,信度达0.001。春季地温对梨树发育期的影响具有明显的持续性和滞后性,冬季地温对梨树发育期影响有阶段性,春季地温对梨树发育期的影响比冬季的明显。

With air temperature data of 140 stations from 1961 to 2000, the 5, 10, 15, 20 cm ground temperature data from 1971 to 2005 and the development period data of pear tree from 1984 to 2005 at Xifeng of the Loess Plateau, the paper analyzed the spring, summer, autumn, winter and annual temperature change of northwest China, the temporal variation regularity of ground temperature and their influences to development periods of pear tree with the correlation computation and the typical year contrast method. The results indicated that： the air temperatures of 1960s at northwest China were warmer in winter while colder in other seasons, the temperatures of 1970s were all changing colder, and the temperatures of 1980s was warmer in winter while colder in other seasons, and the temperatures of 1990s were all warmer with more obvious warming in winter. The 10 cm ground temperatures of Xifeng shows a continual rising tendency in all seasons, the temperature increasing in the spring was most obvious with a rate of 0.058 ℃/a and with the biggest variation range, the second was in winter with a warming rate of 0.039℃/a, and the next was in autumn with warming rate of 0.032℃/a while the smallest was in summer with a rate of 0.029 ℃/a. All of these increasing trends have passed the confidence level tests of 0.05 and 0.01. The winter＇s and the spring＇ s ground temperatures all appeared inverse correlations with various development periods of pear tree, i.e. while the ground temperature was high, the development period of pear tree was earlier and while the ground temperature was low, the development period was later. The winter＇s ground temperatures to the development periods of pear tree showed the most remarkable correlations at the start periods of leave changing and blosso-ming with correlation coefficient from -0.41 to -0.52 and the confidence level of 0.05, the spring＇s ground temperatures to the development periods of pear tree showed the most remarkable correlations at the start period of blos-soming with correlation coefficient from -0.68 to -0.69 and the confidence level of 0.001. The influence of spring＇ s ground temperature to the development period of pear tree has the obvious endurance and the hysteresis effect while the influence of winter＇s ground temperature to the development period of pear tree has the obvious phase effect, so the influence of spring＇ s ground temperature to pear tree was much more obvious than that of winter＇s ground temperature.