广西甘蔗干旱灾变机理与遥感监测预警方法研究

Sugarcane is a pillar of economic crops in Guangxi Province. Both sugarcane’s planting area and yield in Guangxi Province assume absolute superiority in China. Farming of sugarcane in Guangxi is mainly concentrated in dry-lands, where has poor irrigation and the frequency of seasonal drought. Seasonal drought has long been an obstacle to harvest of sugarcane farming and sugar output in Guangxi. Sugarcane cropping has its unique features in comparison to other crops. Very few studies have been done to the mechanism of drought as well as its monitoring in sugarcane cropping under various levels of dryness stress. Objective of this study is to examine the drought mechanism and its monitoring methods. Typical patterns of sugarcane farming will be selected to carry on drought experiments under various levels of dryness stress over sugarcane. The following parameters will be measured from the experiments: sugarcane growing parameters, meteorological parameters, soil water content and temperature at various layers, spectrum of sugarcane leave and canopy, surface temperature of sugarcane leave and canopy, and the harvested yield, biomass and sugar contents. On the basis of these experiments, we intend to examine the impact of seasonal drought on sugarcane growing and its yield and sugar content in the main sugarcane farming regions of Guangxi so that the mechanism of drought hazard to sugarcane cropping under dryness stress and the process of drought occurring in Guangxi can be revealed and understood. In the same time, the temporal and spatial changes and drought disaster risk of sugarcane in Guangxi would be understood. At last, proposed drought remote sensing monitoring and early warning method of sugarcane which would suitable for sugarcane planting in Guangxi. This study would lead to the development of innovative new sugarcane drought theory and monitoring and early-warning method, and improvement of agricultural disaster research level in China.

甘蔗是广西支柱性经济作物，广西的甘蔗种植面积及甘蔗产量在全国均占绝对优势。广西甘蔗主要种植在旱坡地上，灌溉条件差，经常面临季节性干旱，季节性干旱是直接制约广西甘蔗生产和蔗糖产量的最大障碍因素。甘蔗栽培有其特殊性。目前对甘蔗干旱灾变过程、成灾机理和遥感监测预警的研究还极少。项目通过甘蔗种植干旱试验，同步观测甘蔗生长参数、气象参数、土壤各层水热参数、甘蔗光谱和叶冠温度，以及最终甘蔗产量、生物量与含糖率，研究广西甘蔗集中产区降雨季节性不均匀导致的气象干旱对甘蔗生长发育的影响，揭示区域性气象干旱胁迫作用下甘蔗受损成灾过程与致灾机理，认识甘蔗不同生长阶段发生不同程度的干旱胁迫对甘蔗生长发育和最终产量与含糖率的影响，掌握甘蔗集中产区干旱时空变化规律与干旱灾害风险，提出适合于广西甘蔗种植的旱情遥感监测预警方法。项目研究将创新发展我国甘蔗旱灾理论与监测预警方法，提升我国农业灾害研究水平。

甘蔗是广西支柱性经济作物，该省甘蔗的面积及产量在全国占绝对优势。但广西甘蔗主要种植在旱坡地上，灌溉条件差，经常面临季节性干旱，导致甘蔗的产量波动大及含糖率降低，进而影响我国食糖供给稳定。甘蔗栽培有其特殊性，但目前对甘蔗干旱灾变过程、成灾机理和遥感监测预警研究还极少。项目开展了甘蔗种植干旱试验，同步观测甘蔗生长参数、气象参数、土壤各层水热参数、甘蔗光谱和叶冠温度，揭示蔗田土壤水分与温度之间的互相关系，明确叶冠温度、冠层气温与蔗田不同层土壤水分之间的互动关系，初步了解不同生长阶段的甘蔗需水量与根系土层的有效供水量之间的动态变化规律，据此研究提出了多源遥感耦合DSSAT模型的甘蔗旱情预警模型，提出适用于甘蔗苗期表层土壤水分微波遥感反演方法,探索了广西蔗区全生育期干旱长时序时空变化特征，评价CWSI/CWDI/TVDI指数在广西甘蔗干旱旬尺度监测中的适用性。研究新发现蔗田土壤水分与温度之间的互动关系及蔗田不同深度层的土壤温度存在延迟效应，研究可为甘蔗干旱指数设计、植被全覆盖条件下的甘蔗根系土壤水分遥感反演方法研究提供理论参考，为甘蔗旱情监测预警提供技术支持。