The warming trend of the global climate system continues, and the impact on natural ecosystems and water resources continues to rise, aggravating the already fragile global water resources. At this background, as a potential water resource, non-precipitation water (NPW) in arid area plays an important role in the maintenance of ecosystem and land surface water balance in arid area. Therefore, based on the present results of international research on NPW, the development process of NPW is summarized. The observation methods, variation characteristics, formation mechanism and the contribution of NPW to land surface water balance and its effects on crops in arid areas of Northwest China were reviewed. Finally, on the basis of combining the international frontiers, hot issues and development trends of NPW research, the shortcomings and problems of current NPW research are analyzed scientifically. It is pointed out that the study of NPW should focus on further revealing the complex formation mechanism of NPW on land surface, and strengthen the cognition of NPW in different climatic regions and different underlying surfaces. Breakthroughs have been made in key scientific issues such as the establishment of a specially targeted land surface NPW observation system, the development of the parameterization of land surface NPW in the numerical model, and the research and development of technical standards for the development and utilization of land surface NPW.
Drought is a major meteorological disaster with the highest frequency, the longest duration and the widest scope of harm in the world today, which has a huge and extensive impact on agriculture, ecology, social development and national economy all over the world. The drought is an important factor affecting agricultural production which determines the stability of crop production, further relates to the national food security. China is a large agricultural country, and also is a country with frequent drought disaster. Therefore, to improve the monitoring, forecasting and warning level of agricultural drought disaster, it is necessary to deeply understand its formation, influence characteristics, drought intensity, severity and physiological process and mechanism of crop victimization. It is also an important scientific problem to reduce and prevent drought disaster losses and improve national food security production. This paper comprehensively reviews the recent internal and overseas research progress of agricultural drought with different degrees and its impact on crop production, and explores the influence characteristics and mechanism of drought from the aspects of crop morphology, physiology, cellular and molecular levels, etc. The main indicators, indexes, methods and early warning systems in current agricultural drought monitoring are reviewed around food production to cope effectively agriculture drought. According to the new characteristics of agricultural sustainable development and drought, the current situation of drought disaster prevention and mitigation and agricultural drought coping are discussed. A series of drought coping measures both adaptation and mitigation are emphasized. On this basis, combining with the needs of national, regional and industrial development, the paper puts forward the important scientific problems, research countermeasures and the prospect of discipline development which should be emphasized in the future.
