气候变化和物候变动对东北黑土区农业生产的协同作用及未来粮食生产风险

Synergic effects of climate change and phenological variation on agricultural production and its risk pattern in black soil region of Northeast China

东北黑土区是中国重要的粮食生产基地,也是中国气候变化最敏感的地区之一。然而,气候变化背景下东北黑土区气候及物候变化对农业生产力的综合影响并不清晰,未来农业生产风险评估的定量化程度不够,风险等级制定缺乏依据。本文借助遥感产品、气候资料和模拟数据等资料,综合运用多元线性回归、相关分析及干旱危险性指数等方法,探究东北黑土区作物物候动态及其气候响应特征,辨识气候与物候变化对农业生产的复合效应及未来可能风险。结果表明:(1)2000—2017年东北黑土区29.76%的区域作物生长季开始期呈显著延后趋势,16.71%的区域作物生长季结束期呈提前态势,生长季开始期受气温的影响范围广,且滞后时间长;生长季结束期与前期气候变化关系更加密切,且带状差异性响应格局尤其明显。(2)气候变化和物候期改变对作物生产的解释能力较生长季同期气候变化的解释能力增加了70.23%,解释面积扩大了85.04%。(3)RCP8.5情景下东北黑土区粮食总产量呈现上升趋势,粮食生产风险表现出“南增北减”的演变特征,风险区面积不断扩大,全球温升2.0℃时,松嫩黑土亚区南部粮食减产量可能达到10%。研究有助于深入认识气候—物候—作物生产的关联机理及未来粮食生产风险,对制定气候变化应对策略,保障国家粮食安全具有重要意义。

The black soil region of Northeast China is the major food base and one of the most sensitive regions to climate change in China. However, the characteristics of crop phenological response, the integrated impact of climatic and phenological changes on agricultural productivity in the black soil region of Northeast China under the background of climate change are not clear, the quantitative degree of future agricultural risk assessment is insufficient, and the risk level formulation lacks a basis. Therefore, based on remote sensing products, climate data and model simulations, this study integrated the logistic function fitting curvature derivation, multiple linear regression and scenario simulation to investigate the crop phenology dynamics and its climate response characteristics in this black soil region, and to identify the compound effects of climate and phenology changes on agricultural production and possible future risks. Results show that:(1) From 2000 to 2017, about 29.76% of the black soil region of Northeast China showed a significant delay in the onset of the growing season and16.71% of the total area showed an advancing trend in the end of the growing season. The time lag effects of the onset of the growing season for crop response to climatic factors depended on site and climatic parameters, with the widespread influence of temperature and its lag time longer in general.(2) Both climatic and phenological changes have a significant effect on the interannual variability of crop production, and the explanatory capacity of both increased by70.23% and the explanatory area expanded by 85.04% compared to that of climate change in the same period of the growing season.(3) Under RCP8.5 scenario, the future crop yield would show a decrease in the north and increase in the south, and when the global temperature rises by 2.0 ℃, the crop yield of southern Songnen black soil subregion would reduce by nearly10%. Spatial and temporal variation of drought would adversely affect crop production. The study will help to understand the mechanisms underlying climate change, phenological response and productivity dynamics, and also help to strengthen the risk management of agrometeorological disasters, which is important to ensure national food security and regional climate change response.