基于气温变率的东北玉米生育期和产量变化响应机制研究

Climate change has an significant impacts on crop production. It has received considerable attention for a long time. In addition to the warming trend, climate warming also has obvious interannual and interdecadal variations. However, previous studies focused mainly on the response of crop to changing mean temperature conditions. In this study, we emphasize the response of maize to temperature variability in Northeast three provinces of China, which is the major grain production region and has experienced the most prominent warming in China. Nearly 30 years of maize growth and yield observation data and daily temperatures were collected from 1981-2010. Firstly, to analyze the variability characteristics of multiple heat index in the maize growing season over the past 30 years at different time scale. Secondly, to detect the spatial and temporal variation characteristics of maize growth stage and yield. Thirdly, the statistical model will be used to extract the key thermal factors causing maize growth and yield changes. And then, crop model is applied to reveal response mechanisms of the maize changes in growth period and yield to the key thermal factors variability in the spatial and temporal scale. Results of this study could further enrich the understanding of the theoretical response mechanisms for food security research in the field of climate change impacts on crops. Meanwhile, the response mechanisms may also provide a scientific basis to develop the adaptive strategies in the context of future climate change and regional agricultural production plan.

以增温为主的气候变化对粮食作物生产有着显著影响,长期以来受到人们广泛关注。气候变暖除具有平均态的增温趋势外,还存在明显年（代）际变率特征。已有研究多为作物对气温平均态变化的响应，缺乏对气温变率的响应分析。本项目选择我国增温速率和幅度最为显著的粮食主产区-东北三省为研究区域，以主要粮食作物玉米为研究对象，利用近30年（1981-2010年）的玉米生育期和产量观测数据、逐日气温观测数据，识别不同时间尺度的玉米生长季内各热量指标变率特征，分析玉米生育期和产量时空变化规律，采用统计模型和作物模型相结合的方法，提取引起玉米生育期和产量变化的关键热量因子，分析东北三省玉米生育期和产量变化特征对关键热量因子变率的时空响应机制。研究结果在理论上丰富了粮食安全研究领域对气候变化的影响作用及农作物的响应机制的认识，在实践上为区域应对气候变化策略和制定区域农业生产规划提供科学依据。

气候变暖对作物产量形成有显著影响。本研究利用玉米历史观测数据、历史气候数据以及统计资料，分析了玉米生育期和产量的变率特征，结合统计模型和作物模型，模拟分析了玉米产量变率与气候因子变率间的相互关系，定量评估各个因子在玉米产量提高过程中的贡献率。主要的结果表明：1）中国东北南部、华北南部、西南地区是典型生育期出现日序波动幅度较大的地区。东北地区，黑龙江和辽宁多呈现出成熟期变化幅度较大，分别占58%和56%的站点比例，吉林省玉米播种时间变化幅度较大；玉米营养生长期和生殖生长期的生育期日数变率值高于全生育期的持续日数。2）东北玉米生育期内日最低温增温趋势显著且更为普遍；所有站点均存在日最高温增加趋势，但仅有半数站点增加显著。气温变率对产量的影响均为负效应，且呈现出单一受最低气温波动或最高气温波动的产量损失比率高于共同受二者波动影响下的产量损失。3）自1980s以来玉米单产呈增加趋势，单产变率呈现显著下降趋势。东北地区的玉米产量变率对开花期的温度亏缺值、生殖生长期的积温和总降水值变率的敏感性显著。当此三个因子变率增加10%时，产量变率相应增加2.39%、5.44%和4.04%。4）生长季积温每增加1%，玉米产量增加0.87%。过去30年间，温度升高促使玉米产量增加5.2%。玉米产量增加的原因也主要源于农业生产资料投入的增加（88.6%）。温度和日照对玉米产量重心迁移影响显著，仅受温度或日照影响下的玉米产量重心空间变化与实际玉米产量重心空间变化相一致。玉米生长季内降水对产量重心也呈显著性影响，但受降水单一因子影响下的产量重心空间变化与实际水稻产量重心空间变化不太一致。本研究对玉米产量变化与气候波动之间关系的解析可为玉米生产应对未来气候变化提供理论依据。