关中近40a冬小麦生育期热量资源变化及影响分析

Characteristics of heat resources in winter wheat growing seasons and its impacts in Guanzhong area over last 40 years

利用关中10个代表站点1971-2010年气象资料和1986-2010年冬小麦生育期观测资料,采用数理统计方法分析冬小麦生育期热量资源变化及其影响。结果表明：近40a关中热量资源总体呈增加趋势,但年际波动较大,90年代增温较为明显。≥0℃初日呈明显提前趋势,终日略有推后,冬小麦越冬期推后。80年代开始14℃终日推后,18℃终日提前,冬小麦适宜播种期延长。≥0℃积温及日数呈明显增加趋势,越冬期负积温及日数均呈减少趋势。1986-2010年小麦生育期≥0℃积温平均增加180（℃·d）·10a-1,生育期天数减少6d·10a-1。冬前积温≥500℃·d且≤700℃·d保证率达80%的适宜播期为9月28日-10月11日。随着热量资源的增加,冬小麦适宜播期应比传统播期延迟3-5d,利于防止小麦旺长受冻。但实际播期受多种因素影响,应依据实际气候特点播种,提高热量资源利用率。

Based on the observed data of 10 conventional meteorological stations in Guanzhong area from 1971 to2010 and investigated data of winter wheat growth periods from 1986 to 2010,heat resources changes in the winter wheat growth period and their variation effects were analyzed by using mathematical statistic method. The results show that heat resources increasing trend was evident in the recent 40 years,although the serious inter-annual fluctuation existed,warming trend increased sharply in 1990s. The beginning date of 0℃ was obviously advanced,it＇s terminal date was delayed and overwintering period was delayed correspondingly. The terminal date of 14℃ advanced and the terminal date of 18℃ postponed since 1980s,the suitable stage of winter wheat planting was extended. There was a very obvious ascending trend for the accumulated temperature above 0℃ and continuous days,the winter negative accumulated temperature and overwintering period was decreasing. The total accumulated temperature above 0℃ in growth period of winter wheat increased by 180（ ℃ ·d） ·10a-1during1986-2010. The days of the growth period of winter wheat decreased by 6d·10a-1. The suitable sowing time was Sep 28th to Oct 11th which the accumulated temperature above 0℃ before wintering of wheat from 500℃ ·d to 700℃ ·d at 80% of guarantee rate. The optimum sowing time should delayed 3 - 5 days than regular time with heat resources increasing,which help to prevent prosperous grow before winter. The sowing time was influenced by several factors,so the practical sowing time should work out according to local conditions to raise the utilization rate of heat resources.