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ABSTRACT Potential evapotranspiration represents the maximum evaporative capacity for a region, which underscores the importance of analysing its changes and attribution to provide information for water resource management. This study focused on the northern Loess Plateau of China, investigated the changes in potential evapotranspiration ( ET0) using data from 34 stations during 1960-2013 and conducted its temporal and spatial attribution through the differentiation equation method. The results show that the annual mean ET0 is 1004.9 mm with a decreasing trend at the rate of 0.33 mm year−1. The lowest values were found in the northeast and southwest regions, while the greatest ET0 was in the northwest region. An 'evaporation paradox' existed as a whole, but not obviously. The ET0 was most sensitive to actual vapour pressure ( ea), followed by solar radiation ( Rs), mean temperature ( Tmean) and wind speed ( U2). The inter-annual variation in the sensitivity of ET0 in relation to climatic factors showed that ET0 became more sensitive to U2 and Tmean but less sensitive to Rs and ea from 1960 to 2013. Temporally, the increasing Tmean resulted in the increase of ET0; while its effect was weakened by the other three factors, especially by decreasing U2. The contributions of climatic factors to the ET0 spatial variation trends were also analysed along two transects, but the dominant factors were different for each transect. Furthermore, the possible impacts of human activities on ET0 changes were also discussed. [ABSTRACT FROM AUTHOR]

The use of adapted crop cultivars is an effective approach to cope with climate change. The objective of this study was to evaluate the impacts of climate change and the use of later-maturing cultivars on winter wheat yields and soil water deficit in dryland farming on the Loess Plateau of China. The later-maturing cultivars of winter wheat ( Triticum aestivum L.) were generated by increasing the growing degree day requirement according to Root Zone Water Quality Model 2. The results showed that the wheat yields and water use efficiency were significantly improved by the later-maturing cultivars and fluctuated along with precipitation trends. The downward trend of wheat growth duration due to climate warming conditions was effectively counteracted and even reversed by introduction of the later-maturing cultivars. Increased precipitation during the longer growth period of the later-maturing cultivars partly compensated for the wheat evapotranspiration, so that the soil water deficit level was maintained or even reduced. The results of this study contribute to gaining improved understanding of the effective phenotypic characteristics of dryland winter wheat to cope with climate change using model-based assessments. [ABSTRACT FROM AUTHOR]