长江中下游热量资源时空演变特征及其对双季稻种植的影响

热量资源的时空特征是影响双季稻种植布局的主要气候因素.为了分析近52年长江中下游主要双季稻区热量资源的变化特征及其对双季稻种植的影响,本研究选取湖南、江西和湖北3省作为双季稻代表性研究区域,根据3省240个气象站1961—2012年的地面气象观测资料,利用气候倾向率及突变分析等方法,分析研究区双季稻温度生长期的热量资源和双季稻的安全生长期的演变规律,在此基础上分析研究时段内不同水稻品种搭配布局及种植北界的变迁.结果表明: 近52年双季稻温度生长期及安全生长期的热量资源均呈明显增多趋势,其中,双季稻生长期及安全生长期的热量资源由寡至多的突变点均出现在2000年;双季早稻安全播种期提前3～7 d、双季晚稻安全齐穗期延后2 d,双季稻安全生长期平均延长7 d;双季稻种植北界明显北移了200 km左右,至33° N附近;同时,双季稻品种搭配由“早熟早稻+中熟晚稻”和“中熟早稻+中熟晚稻”向“中熟早稻+晚熟晚稻”转变.长江中下游双季稻区热量资源的增加为双季稻种植北界北移、中晚熟品种替代早中熟品种提供了可能.

Spatial-temporal characteristics of thermal resources and its influence on the growth of double cropping rice in the middle and lower reaches of the Yangtze River,China.

The spatial-temporal characteristics of thermal resources are the main factor controlling the spatial distribution patterns of double cropping rice. Based on daily average temperature data collected from 240 weather stations in Hunan, Jiangxi and Hubei provinces, our study analyzed the change characteristics of thermal resources during thermal growth period and safe growth period of double cropping rice in the middle and lower reaches of the Yangtze River. Furthermore, we quantified the change trends of spatial pattern for the rice cropping systems with different rice varieties and the northern limit of double cropping rice. The results indicated that the thermal resources of double cropping rice displayed a significant increasing trend during both thermal and safe growth periods, with an abrupt change in 2000 in terms of the Mann-Kendall test. The safe planting date of early rice advanced for 3-7 days and the safe heading date of late rice delayed for 2 days. Averagely, the safe growth period extended by about 7 days, and the planting northern limit of double cropping rice shifted 200 km northward, approaching to the latitude of 33° N. Meanwhile, many areas with cropping systems of ‘early maturing early rice + mid-maturing late rice’ and ‘mid-maturing early rice + mid-maturing late rice’ were replaced by ‘mid-maturing early rice + late-maturing late rice’. Our study revealed the feasibility to shift the double cropping rice system northward and replace early and mid-maturing rice variety with mid and late maturing rice variety due to the increa-sing thermal resources during growth period of double cropping rice under climate change.