河北平原冬小麦播种面积收缩及由此节省的水资源量估算

以河北平原1998-2010 年11 地市的农业统计数据和22 个气象站点的逐日气温、降水量、水汽压、风速、日照时数和相对湿度等资料为基础,对该地区冬小麦播种面积的收缩情况及由此引发的耕作制度变化进行了分析;同时,结合作物系数法和逐旬有效降水量法,计算了不同耕作制度下的水分亏缺量,进而估算了该地区因耕作制度变化节省的水资源量。结果表明:① 该时段河北平原11 地市冬小麦的播种面积均呈收缩趋势,总面积下降了16.07%,约49.62×10⁴ hm²。京津唐城市群表现最为明显,下降了47.23%;② 冬小麦的降水满足率仅为20%~30%,而春玉米和夏玉米均为50%以上;冬小麦-夏玉米一年两熟制所需的灌溉水资源量为400~530 mm,而春玉米一年一熟制仅为160~210 mm;③ 该时段河北平原因冬小麦播种面积收缩而节省的灌溉水资源量约为15.96×10⁸ m³/a,相当于南水北调中线一期工程为京津冀三省市供水量的27.85%。

Impact of the shrinking winter wheat sowing area on agricultural water consumption in the Hebei Plain

This study firstly analyzed the shrinkage of winter wheat and the changes of cropping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, including daily temperature, precipitation, water vapor, wind speed and minimum relative humidity data from 22 meteorological stations, and then calculated the water deficit and irrigation water resources required by different cropping systems, as well as the irrigation water resources conserved as a result of cropping system changes, using crop coefficient method and every ten-day effective precipitation estimation method. The results are shown as follows. 1) The sowing areas of winter wheat in all the 11 cities in the Hebei Plain shrunk during the study period. The shrinkage rate was 16.07% and the total shrinkage area amounted to 49.62×10⁴ ha. The shrinkage was most serious in the Beijing-Tianjin-Tangshan Metropolitan Region, with a rate of 47.23%. 2) The precipitation fill rate of winter wheat was only 20%-30%, while that of both spring maize and summer maize exceeded 50%. The irrigation water resources demanded by the winter wheat-summer maize double cropping system ranged from 400 mm to 530 mm, while those demanded by the spring maize single cropping system ranged from 160 mm to 210 mm. 3) The water resources conserved as a result of the winter wheat sowing area shrinkage during the study period were about 15.96×10⁸ m³/a, accounting for 27.85% of those provided for Beijing, Tianjin and Hebei by the first phase of the Middle Route of the South-to-North Water Diversion Project.