华北冬小麦拔节孕穗期干旱灾变过程解析与识别

Understanding the mechanism of agricultural drought disaster, and accurately identifying the evolution process including latency, onset, and hazard or recovery, is with high priority for carrying out the pre-disaster prevention, disaster and post-disaster remedy. Currently, little research has focus on the whole evolution process of agricultural drought , with its characteristics and key nodes still lacking. In this research project, agricultural drought of winter wheat in jointing-booting stage in North China will be targeted to highly precision and recognition of its evolution process, integrating field experiment of water control and regional disaster inversion method. The field experiments of controlling water in different intensity will be applied firstly to observe the responses of physiological ecology and yield of winter wheat under drought conditions. Afterwards, disaster evolution samples in North China will be constructed with the aid of the ground observation and remote sensing data, and evolution regularity and identification technology in regional scale will be proposed based on such evolution samples and field experiments results. The purposes of this project are (1) to investigate the impact mechanism of drought in winter wheat in jointing-booting stage; (2) to identify its drought evolution regularity in North China; (3) to develop recognition technologies of drought evolution process in regional scale.

明确农业干旱灾变机制，准确识别灾害潜伏、发生、成灾或消亡的过程，对及时了解农业干旱发生、发展、消退情况，合理开展灾前预防、灾中减损和灾后补救措施有重要意义。而目前，鲜有研究将整个农业干旱灾变过程（包括灾害潜伏、发生、成灾/消亡）作为研究主体，干旱潜伏、发生、成灾/消亡的灾变特征及关键节点尚不明晰。鉴于此，本研究选择华北平原冬小麦拔节孕穗期干旱灾变过程为研究对象，利用田间控水试验，研究干旱条件下冬小麦生理生态响应机制；借助地面观测和遥感手段，实现华北平原冬小麦拔节孕穗期干旱灾变规律高精度反演；以对比试验观测数据为校验，率定干旱发生、成灾关键节点，研发区域尺度冬小麦干旱过程（潜伏、发生、成灾/消亡）分阶段识别技术。

农业干旱是指在农作物生长发育过程中，因降水不足、作物得不到适时适量的灌溉，致使供水不能满足农作物的正常需水而造成农作物损伤。作物干旱的发生发展过程可概括为：（1）潜伏期：降水减少，但未影响作物生理生态；（2）发生期：由于降水或灌溉亏缺，作物遭受水分胁迫，生理生态受到影响；（3）成灾/消亡期：成灾表现为随着降水或灌溉亏缺持续，作物植株生理机能受损。本研究选择华北平原冬小麦拔节孕穗期干旱灾变过程为研究对象，借助地面观测和遥感手段，实现华北平原冬小麦拔节孕穗期干旱灾变规律高精度反演；通过灾变过程样本再分析，率定干旱发生、成灾关键节点，研发区域尺度冬小麦干旱过程分阶段识别技术。结果表明：采用相对湿度RH和作物耗水盈亏指数CWDI能较好的反映冬小麦拔节孕穗期干旱灾变过程；当相对湿度下降至46.78时达到作物干旱响应的临界值，冬小麦蒸散能力下降；华北平原冬性和弱冬性冬小麦拔节孕穗期干旱成灾临界阈值分别为耗水盈亏指数CWDI 0.86和0.84。研究结果对及时了解农业干旱发生、发展、消退情况，合理开展灾前预防、灾中减损和灾后补救措施有重要意义。