河北省近35年农作物需水量变化趋势分析

Trend of crop water requirement in recent 35 years in Hebei Province

根据联合国粮农组织（FAO）推荐的参考作物蒸散计算方法和相关作物系数,利用河北省84个地面气象站的资料,计算了河北省主要作物冬小麦和玉米近35年（1965～1999年）的需水量和缺水量,并分析了其变化趋势。结果表明：河北省主要作物冬小麦和玉米的需水量在近35年呈减少趋势,每10年下降量冬小麦全省平均26mm,其中中南部地区28mm,东部地区15mm;夏玉米全省平均9.7mm,其中南部地区9.4mm,中部地区10.2mm;春玉米全省平均9.9mm,其中东部地区8.8mm,北部地区10.5mm。全省和各区域作物需水量变化均通过0.05信度的显著性检验。不同作物缺水量不同,其中冬小麦最多,全省平均345mm,夏玉米20mm,春玉米29mm;虽然不同作物均表现出缺水增加的趋势,但不显著。

Long term changes of crop water requirement （CWR） and reference evapotranspiration have a significant effect on agri- cultural production and water resources management. Based on historical meteorological data, reference evapotranspiration （ETo）, crop water requirement （derived by multiplying ETo by crop coefficient） and crop water deficit （the difference between crop water requirement and rainfall） were calculated using modified FAO Penman-Monteith equation. The change trend was then analyzed for winter wheat and maize in Hebei Province for the period 1965 1999. Results show a significant decrease in reference evapotranspi- ration and crop water requirement. Decrease in CWR is 26 mm per decade for winter wheat and 9.7 mm and 9.9 mm for summer and spring corn respectively. There are differences in water deficit among different crops but the average increase in water deficit is in- significant, which is respectively 345 mm, 20 mm and 29 mm per year for winter wheat, summer corn and spring corn.