| Recently, climate warming has aggravated not only spatial and temporal distribution of the precipitation unevenly, the crop water requirement has also stood a tremendous influence, affects allocation of agricultural water consumption thereby. Moreover, Planning and design of irrigation projects and water diversion project need estimating the crop water requirement in the irrigation district accurately. Therefore, study on the impact of climate change over crop water requirement, temporal distribution and building spatial distribution model of crop water requirement are very important for replying climate change, adjusting agriculture structure, guiding irrigation project plan and making use of water resource rationally.This paper took Baojixia irrigation district as the research region. On the basis of the influence of climate on crop water requirement, temporal and spatial distrbution of water requirement was researched in Baojixia irrigation district. The main conclusions were as follows:(1) Crop water requirement of four kinds of plants on each station in the irrigation district has been calculated. The results show that water requirement of plants all showed a trend of undulatory increase in the recent thirty years. The intraannual variation of crop water requirement for each plant has great differences, as winter wheat water requirement of April is maxima, maize water requirement of July and August is more, cotton water requirement of July is maxima, and rape water requirement from March to June is more than other month.(2) The impact of climate change over crop water requirement in the irrigation district was reseached using Kendall method and grey relational analysis mothod. It was shown that temperature rises, the increase of potential evaporation and the increase of sunshine duration are the main influence factors, leading to the increase trend of crop water requirement, in which the temperature is the most significant factor.(3) The multi-timescale analysis of water requirement of each plant in the irrigation district was studied from 1981~2008, according to Morlet wavelet theory. The result indicate winter wheat water requirement sequence shows fifteen times alternation of bigness priod and smallness on 3~5 years scale. Maize water requirement sequence shows fifteen times alternation of bigness priod and smallness on 3 years scale and six times alternation on 6 years scale. Cotton water requirement sequence shows ten times alternation of bigness priod and smallness on 4 years scale. Rape water requirement sequence shows sixteen times alternation of bigness priod and smallness on 3 years scale and eight times alternation on 5 years scale.The trend of the water requirement of each plant was reseached using spearman trend analysis. It was shown that the water requirement of every plant has increase trend. Basis on this trend, GM (1,1) model of crop water requirement was obtained, and the precision of this fitting is high.(4) Spatial variation of crop water requirement was studied basis on the geo-statistics. The result shows that cotton water requirement was the most in the four kinds of plants, as 636.8~683.4mm, maize water requirement was the minimum, as 636.8~683.4mm, the water requirement of winter wheat and rape were 490.1~538.1mm. Although the spatial variation rule of water requirement of four kinds of plants was different, all of crop water requirement show the obvious trend from southwest to northeast. From west to east, the crop water requirement nearby Baoji station in the western region was larger, the water requirement on Meixian station was smallest, to east, the crop water requirement enhanced gradually, reaching maximum nearby Xianyang station. From south to north, It is showed incease tendency.
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