气候变化背景下广东晚稻播期的适应性调整

Adaptative adjustments of the sowing date of late season rice under climate change in Guangdong Province

统计广东86个气象站1961—2009年资料,对气候变化背景下广东晚稻生长季气候资源、气象灾害的变化趋势进行了分析。结果表明,广东晚稻生长季热量资源明显增加,冷害趋于减轻,登陆广东的热带气旋个数减少且影响时间缩短;推算出广东晚稻播期有较大的调整空间,可提早或推后。综合分析认为晚稻播期提早较推后更有利于气候资源的充分利用和气象灾害的减轻。通过分期播种试验分析了当前广东晚稻主栽品种在各地区播期提早或推后对生育期和产量的影响,结合气候因子和耕作习惯等因素,认为晚稻播期提早优于推后。建议广东晚稻播期各区的调整方案为:北部可提早8—9 d,中部可提早10—12 d,南部可提早12—15 d。

Based on daily climatic data collected from 86 weather stations from 1961 to 2009 in Guangdong Province,the characteristics of climate resources and meteorological hazards during growing season of late season rice cultivars were analyzed under climate change.The main conclusions were：（1） climate resources had changed since 1997.Average air temperature increased 0.7℃ than that of the contrast（1961—1996）.Above 10℃ accumulative temperature increased 82 ℃.Climate warming effects was accelerated since 1997.The heat resource significantly improved during the growth period of late season rice in Guangdong province.Sunshine hours during the growing season slightly decreased 58 hours than that of the contrast.Total precipitation during growing season showed insignificant change but an increasing yearly variability;（2） Since 1997,the date of the first-landfall tropical cyclone（TCs） was postponed in Guangdong,but the date of last-landfall TCs launched earlier.The number of TCs landed in Guangdong province decreased mainly in autumn during September to October,but the number of Typhoon（TCs with wind power≥12 grade） increased.Since 1997,the probability of TCs which landed at the southwest coastal was 70%,showed no noticeable changes than that of the contrast（1961—1996）.Thus,TCs would none the less threat the late maturing rice in southwest coastal of Guangdong.The probability of Typhoon,which landed at the southwest coastal significantly increased from 67% to 82%,will aggravate the threat of the late maturing rice;（3） Since 1997,the beginning date of the cold dew wind weather（CDWW） and the frost′s descent wind weather（FDWW） postponed 7 d and 11 d,respectively,while the total days of CDWW and FDWW showed no significant difference.The beginning date of CDWW postponed 5—15 days in the southern region,4—5 days in middle region,and 1—4 days in the northern region.The beginning date of FDWW postponed 10—20 days in south,5—15 days in middle,and 0—5 days in north.Based on the analysis above,we concluded that the heat resource in Guangdong was increased,the events that TCS harmed the late season rice were reduced,and the beginning date of chilling damage was postponed.Therefore,The sowing date of late maturing rice can be earlier or later with higher adjustment potential;（4） Based on the field experiments including different sowing dates and three rice varieties in 2009,the adjustability of the sowing date of late season rice was analyzed by the relationship between the development stage,yield and temperature differences.The results showed that the heat resource during growing period was closely related to the growing days in temperature sensitive cultivars.High temperature shortened the growth period and differed between genetic cultivars,especially at the vegetative stages,such as returning green stage to tillering stage and tillering stage to booting stage.The yield tendency showed a increasing against the increasing daily average air temperature,and then a decreasing when the temperature was higher than 28℃. The earlier sowing date of the late maturing rice would enhance crop productivity and economic benefit in winter season,by optimistically using climate and land resources.Because the farmers like to planting later season rice as earlier as possible in order to save more time for winter crops,the extension of the early adjustment of sowing date for late maturing rice will faced less difficulties.With integrating the results of this study and climatic factors,previous experimental studies,cropping systems and farmer＇s practice etc.,we suggest that the sowing date of late season rice should be 12 to 15 days earlier in the southern region,10 to 12 days earlier in middle region and 8 to 9 days earlier in the northern region.