关键词: 威百亩, 威百亩, 土壤, 微生物数量, 酶活性

Abstract: The paper aims to fully understand the climate characteristics of frost-free period in Baoding Area, and provide a reliable basis for agricultural meteorological service. The author analyzed the distribution characteristics and changing trend of frost in Baoding in recent 50 years based on the observation data from 13 weather stations in Baoding. The results indicated that in Baoding Area, the first frost, last frost and frost-free period had obvious geographical distribution characteristics. The last frost date of the northwest mountainous area was later than that of the plain area, and the first frost date was earlier in the plain area. The length of frost-free period varied greatly across Baoding. Shunping’s frost-free period, which lasted 194 days, was the longest in Baoding, while the shortest was 139 days, which was in Laiyuan that lied in the mountainous area of the northwest Baoding. There was a big difference of 55 days between the two. For most weather stations in Baoding, the frost-free period had become longer with delayed first frost and earlier last frost. This prolongation of frost-free period is more obvious in Laiyuan, whose climate tendency rate was 5.84 d/10 a. The prolongation was the coordinated effect of delayed first frost and earlier last frost. Moreover, earlier last frost contributed more to the prolongation of frost-free period than delayed first frost.