冀京津冬小麦灌溉需水量时空变化特征

利用冀京津地区20个气象站点1961-2010年气象资料和1980-2009年冬小麦生育期资料,采用美国农业部土壤保持局推荐方法计算有效降水量,同时利用FAO推荐的Penman-Monteith方法计算冬小麦全生育期和4个主要生育阶段的需水量,并对冬小麦生育阶段灌溉需水量进行探讨。结果表明,过去50a来,冀京津冬小麦生育期内有效降水量呈增加趋势,空间上呈经向分布特点,表现为从西向东梯状增加的趋势。而冬小麦的需水量呈减少趋势,其中抽穗-乳熟期减少幅度最大,全生育期需水量的空间分布呈带状特征,全区差异较大。抽穗-乳熟期分布由东南向北递减。为满足冬小麦需水要求,全生育期灌溉需水量为291~381mm,灌溉需水量较多的地区为沧州市和衡水市一带。其中需水较多的生育阶段为拔节-抽穗期和抽穗-乳熟期。在空间上,拔节-抽穗期灌溉需水量以沧州市为中心,向南北两侧递减;抽穗-乳熟期灌溉需水量南高北低,有明显的带状分布特征。研究结果可为冀京津冬小麦适时定量灌溉和提高水分利用效率提供基础数据支撑。

Spatial and Temporal Variation of Irrigation Water Requirement for Winter Wheat in Jijingjin Region

Temporal and spatial distribution characteristics of crop water requirement and irrigation water requirement are the bases for determining the irrigation quota in different regions. The objective of this study is to analyze irrigation water requirement of winter wheat in growth stages to improve the efficiency and productivity of irrigation water in Jijingjin region, and to ensure the food security. Based on data from 20 meteorological stations during 1961 to 2010 and phonological data of winter wheat during 1980 to 2009, using the Penman-Monteith method recommended by FAO, the spatial pattern of the reference crop evapotranspiration was calculated and water requirement in different growth stages for winter wheat were analyzed. And the irrigation water requirement distribution of winter wheat during different growth stages in Jijingjin region during the recent 50 years were analyzed using the crop water surplus deficit index. The results showed that the effective rainfall of winter wheat during the different growth stages and the whole growing period was increasing, while the water demand of winter wheat during the different growth stages and the whole growing period showed a decreasing trend. There was a significant shrinking tendency during heading to milk-ripe stage. The change of the effective rainfall and water demand would promote the evolution on agricultural irrigation. To meet the need for the growth of winter wheat, the total supplementary irrigation amount was around 291 to 381mm. More irrigation water requirement of region was in the city of Cangzhou and Hengshui. Some specific differences also existed in supplementa irrigation water condition and short tern） change. Respectively, the period of the more supplementary irrigation was jointing to heading stage which declined from the center of Cangzhou city and heading-milk stage which increased from the north to the south. The conclusions were important to be applied to the monitoring of water change and provide theoretical basis for strategies of guiding the irrigation timing and amount.