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Titre : Effect of Climate Change on Crop Water Requirement and Water Saving Potential of Baojixia Irrigation District in Northwestern China

Auteur : 丁浩；

Grade : Doctoral Dissertation 2017

Université : Northwest A&F University

Résumé partiel
Affected by global climate change,the frequency of extreme weather events becoming more and more,resulting in the safe of water resources suffered a great challenge in China,especially irrigation water,immediately threaten to the country’s food security.Baojixia Irrigation district is the largest irrigation districts in Shaanxi province.Agricultural production of Baojixia Irrigation district and the whole national economy and social development has played an extremely important role in Shaanxi Province.In this study,the Baojixia Irrigation district as the main object,considered the climate data,main crops,irrigation district agriculture development and other factors were affected on crop water requirenment.The impact factors of irrigated agriculture and the temporal and spatial variation of water requirement,as development of agricultural irrigation development planning under climate change conditions,determine a reasonable crop irrigation quota and cropping systems,and provide a reference for addressing climate change response measures.Through this study,the main results are as follows :⑴ Due to climatic variation is random,and the volatility fluctuations,so this paper calculates the average value of each meteorological factors based on time series data,to eliminate the effects of fluctuations in the random factors,and to show and forecast trends meteorological factors.According to geographical location and meteorological data of 12 meteorological stations in Baojixia Irrigation district,and calculated data of the main crop growing period between 1961 and 2010,including the average temperature,the maximum temperature,minimum temperature,temperature and wind speed level,the average relative humidity,sunshine and precipitation.It was used time series analysis method to explore the evolution of various meteorological factors in Baojixia Irrigation district.The results shown : the average temperature,the maximum temperature and minimum temperature of Baojixia irrigated area in 50 years overall showed volatility on the rise,and the maximum and minimum temperaturefrom 1985 showed significant warming effect stately.Although showing frequent volatility in Baojixia Irrigation district of the average precipitation irrigation and standardized precipitation index(SPI)in time series,but time series of rainfall with SPI on the overall downward trend,and the extents of the past 20 years more and more irrigation meteorological drought seriously.The frequencies of drought were occurrence more and more,which resulting in the trend of warm and dry in Baojixia Irrigation district.In addition,the cyclical changes of relative humidity,wind speed and sunshine on a long time scale is not obvious differences.In addition,hurst exponent analysis method and wavelet analysis method also showed that : the average temperature,maximum temperature,minimum temperature and relative humidity of irrigation district were shown increased trends,while wind,sunshine hours,precipitation and SPI were shown decline trends.After a comprehensive analysis of the results of different research methods,the future of meteorological factors of Baojixia irrigation district in the future for a long time,the direction of change will be warmer and drier.⑵Calculated within each meteorological site of Baojixia all major crops for many years and the average annual water demand change from year trend analysis on the time scale.The results shown : Cotton is the main crop in the four largest crop water demand,from 1961 to2010 annual average water demand of cotton reached 626.34 mm/a,the average daily water demand in the years between 1.53 4.70 mm/d ;followed by canola,water demand is 574.38mm/a,for many years the average daily water demand between 0.84 3.00 mm/d ;water demand of summer corn is smaller,for 468.61 mm/a,for many years the average daily water demand between 3.20 5.03 mm/d ;

Mots clés : Baojixia irrigation district； crop water requirement； irrigation requirement； climate change；

Présentation (CNKI)