气象因子对江苏省水稻单产的影响

Meteorological effects on rice yields in Jiangsu Province

全球气候变暖作为一个不争的客观事实,不可避免地对农业生产产生影响。针对传统多元线性回归分析方法,不能直接分析气象因子与水稻气象单产时序关系,根据1978—2010年间江苏省水稻单产数据和同期气象时序数据,研究了水稻单产的影响因素,提取了水稻气象单产;利用连续小波变换方法研究了水稻气象单产、水稻营养生长与生殖生长期间的日照时数、降水和气温等气象因子的时序变化特征;利用交叉小波和相干小波变换方法,研究了水稻营养生长与生殖生长期间气象因子与水稻气象单产间的相互影响关系。结果显示:(1)近33 a间,江苏省水稻气象单产占实际单产的比重逐渐减小,水稻生产抵御气象灾害能力逐渐增强。(2)水稻气象单产与日照时数、降水量和气温等气象因子有几乎一致的特征周期。(3)在水稻分蘖期、孕穗期与开花结实期,气象单产与日照时数、降水量和气温间的相位差关系较为复杂。水稻分蘖期日照时数的增多有利于水稻单产的增加,降水的增多导致水稻单产的下降。水稻开花结实期日照时数的增强、昼夜温差的变大有利于水稻单产的增加,夜间最低气温的上升会导致水稻单产的下降。为了应对全球气候变暖,需要进一步改变水稻种植方式,加强土地利用监管,积极开展农村土地综合整治,加强高标准基本农田建设,加大农田水利设施建设,调整作物播种期,加强气象灾害应对防范体系建设,更好地发挥生物技术在适应气候变化中的作用。

Global warming impacts agricultural grain security production in China. We investigated the time series relationship between rice yields and meteorological factors, which are not directly analyzed using traditional multiple linear regression analysis. We obtained rice yield data from the Statistical Yearbook of Jiangsu Province and meteorological data from the China Meteorological Data Sharing Service Network for the period 1978 to 2010. We applied continuous wavelet transform, cross-wavelet and coherent-wavelet methods to analyze changes in rice yields related to meteorological factors such as sunshine hours, precipitation and temperature during rice vegetative and reproductive growth stages. Our results show that the proportion of rice yields affected by meteorological factors in Jiangsu Province decreased from 1978 to 2010 because the ability to withstand weather disasters improved. The continuous wavelet transform period characteristics of rice meteorological yields and meteorological factors such as sunshine hours, precipitation, temperature, the highest temperature, the lowest temperature,and day/night temperature difference are almost similar. Our cross-wavelet and coherent-wavelet transform analyses indicate that the phase difference relationship between rice yield and meteorological factors is complex during seedling tillering, booting development, and blossom fruiting stages. During the seedling tillering stage, an increase in sunshine hours increases rice yields, and an increase in precipitation decreases rice yields. During the blossom fruiting stage, an increasing amount of sunshine hours and large day/night temperature differences increase rice yields; small day/night temperature differences decrease rice yields. To mitigate the effects of global warming, rice cultivation procedures need to change. Land use supervision and management as well as rural land consolidation and high-standard basic farmland construction should be strengthened, farmland water conservation facilities need to be improved, and crop sowing times should be adjusted. Technological devices to predict extreme weather disasters should continue to improve and new biotechnology techniques should be implemented to ensure that rice yields are high and are not severely affected by climate change. Cross wavelet analysis methods can accurately analyze the relationship between meteorological factors and the rice yields; such analysis also helps to predict rice yield outcomes from current meteorological data. Our results enable officials in government agricultural departments to make informed decisions while implementing new agricultural policies related to the storage and harvesting of rice.