小麦干旱监测技术研究进展与展望

Research progress and prospects of wheat drought monitoring technology

发展小麦干旱监测技术是客观监测小麦干旱程度、准确反映干旱波及范围和持续时间的基础,从而能够对小麦干旱灾害做出预警并有效地评估其影响。本文系统梳理了国内外小麦干旱监测方法,包括基于地面常规观测、基于水分控制试验、基于作物模型模拟和基于遥感手段的4个方面的研究进展。分析表明,基于地面常规观测资料构建的小麦干旱监测指数,更多地考虑到业务和服务的应用需求,具有计算过程简单、资料获取方便、物理意义明确的特点;但其以气象观测要素为主,监测结果与农业旱情存在一定的偏差。基于人工水分控制试验的监测手段,直接与小麦生长状态联系,能反映实际的旱情;但仅靠部分站点的试验监测结果难以反映大范围的小麦干旱状况。作物模型可细致描述作物生长发育的全过程以及作物生长同降水量和土壤水分之间的动态关系;但其监测所需参数较多,模型本地化释用程度不高。遥感技术能够及时、客观地获取大范围地表综合信息,但受到天气状况、地表粗糙度、地形和植被等因素的影响,反演结果具有一定的偏差。因此,对于小麦干旱监测应该针对特定地区和特定生长阶段赋予不同干旱监测指数影响权重,应用综合监测指数以更准确地反映作物干旱状况。

Providing wheat drought monitoring and early warning is of great significance for preventing and mitigating the economic losses caused by drought disasters.The development of wheat drought monitoring technology is the basis for objectively monitoring the degree of wheat drought and accurately reflecting the scope and duration of drought,thereby providing early warning of wheat drought disasters and effectively assessing its impact.This article systematically reviews the research progress of four wheat drought monitoring technologies at home and abroad,including wheat drought monitoring methods based on conventional ground observations,wheat drought monitoring methods based on moisture control experiments,and crop model simulation and remote sensing methods.The analysis shows that the wheat drought monitoring index constructed based on conventional ground observation data takes more into account the application needs of business and services,and has the characteristics of simple calculation process,convenient data acquisition,and clear physical meaning.However,it is mainly based on meteorological observation elements,and there is a certain deviation between the monitoring results and agricultural drought conditions.The technical means of artificial water control experiments are used to monitor wheat drought,which is directly related to the growth status of wheat and can reflect the actual drought situation.However,relying only on the experimental monitoring results from every site is difficult to reflect the large-scale wheat drought.Crop models can provide detailed descriptions of the entire process of crop growth and development,as well as the dynamic relationship between crop growth,precipitation,and soil moisture.However,crop model monitoring requires multiple parameters,and the degree of localization and application of the model is not high.Remote sensing technology can timely and objectively obtain comprehensive surface information on a large scale,but inversion has certain deviations due to the influence of weather conditions,surface roughness,terrain,and vegetation.Therefore,for wheat drought monitoring,different drought monitoring indices should be assigned influence weights for specific regions and growth stages,and comprehensive monitoring indices should be applied to characterize crop drought conditions more accurately.