黄淮海农作区冬小麦需水量时空变化特征及气候影响因素分析

鉴于作物需水量变化趋势对制定灌溉策略与区域水资源配置的重要作用,本文依据黄淮海农作区50个气象台站近50年(1960—2009年)的逐日气象数据,利用SIMETAW模型计算了研究区域7个亚区冬小麦生育期需水量、适宜灌溉量的时空变化趋势,各主要气象因子时空变化趋势以及需水量与气象因子的相关性。结果表明:近50年来,冬小麦生育期需水量呈下降趋势,其中在1970—1999年间显著下降9.21~18.90mm.10a 1;冬小麦需水量多年平均值为452.4 mm;灌溉需要量在不同亚区间变化不同,其中在汾渭谷地水浇地二熟旱地一熟兼二熟区和豫西丘陵山地旱坡地一熟水浇地二熟区呈上升趋势,每10年上升10.02~13.48 mm;生育期降水耦合度仅为0.40。生育期需水量、灌溉需要量在空间上呈现两边多、中间少的分布,在豫西丘陵山地旱坡地一熟水浇地二熟区最高,分别为457.32 mm、335.33 mm;在海河低平原缺水水浇地二熟兼旱地一熟区最低,分别为363.24 mm和247.51 mm。50年来,黄淮海农作区气温显著上升,降水量不显著下降,风速、相对湿度、太阳辐射显著下降;冬小麦需水量下降主要受太阳辐射、温度、平均风速、平均相对湿度、降水的综合影响,其中最主要的气象原因为太阳辐射量下降,温度、日照时数、平均风速与冬小麦需水量呈显著正相关,相对平均湿度与其呈显著负相关。

Spatio-temporal variations of winter wheat water requirement and climatic causes in Huang-Huai-Hai Farming Region

Information on crop water requirement and the changes in this factor in time and space are critical for irrigation schemes,water resources planning and decision-making.Based on observed daily meteorological data in 50 weather stations in 7 sub-zones of Huang-Huai-Hai Farming Region(HFR) in 1960-2009,winter wheat water requirement and irrigation amount were simulated using the modified SIMETAW model.Results showed that winter wheat water requirement decreased from 1960 to 2009,with a significant decrease of 9.21~18.90 mm from 1970 to 1999.Winter wheat perennial average water requirement was 452.4 mm,coupled rainfall degree for winter wheat growing season was only 0.40.Winter wheat irrigation amount varied among different sub-zones,it increased at the rate of 10.02~13.48 mm per decade in western Henan Province and central Shanxi and Shaanxi Provinces.With re-gard to spatial distribution,water requirement and irrigation amount during winter wheat growing season were higher in the periph-eral than in the central regions.Both water requirement and irrigation amount were highest in the west Henan Province with values of 457.32 mm and 335.33 mm.However,winter wheat water requirement and irrigation amount were lowest in the lower Haihe Plain with values of 363.24 and 247.51 mm.While temperature significantly increased,wind speed,humidity and solar radiation significantly decreased and also with an insignificant decrease in precipitation from 1960 to 2009.The negative trend in winter wheat water re-quirement in HFR was mainly attributed to declining solar radiation,which was in turn driven by some other climatic factors.Correlation analysis showed that temperature,sunshine hour and wind speed were positively correlated with winter wheat water re-quirement,while relative humidity was negatively correlated with it.