泾惠渠灌区作物需水量特征及影响因素

Crop water requirement and influence factors in Jinghui Canal irrigation district

通过CROPWAT模型分析泾惠渠灌区冬小麦和玉米蒸发蒸腾量及灌溉需水量的变化,同时运用SPSS软件,计算灌区作物需水量与气象因子的相关系数,分析结果表明:冬小麦整个生育期蒸发蒸腾量平均值为634.04 mm,蒸发蒸腾量最高峰出现在4月中旬—5月中旬,灌区各分区蒸发蒸腾量趋势基本一致;玉米蒸发蒸腾量平均值为525.22 mm,蒸发蒸腾量高峰期出现在7月中旬—8月下旬,其中三原最大为535.97 mm,富平最小为514.68 mm;灌区冬小麦在播种—越冬期灌溉需水量最低,返青—拔节期需水量增加;灌区玉米在拔节—抽雄期需水量增加,灌溉平均需水量为133.04 mm;7月—8月为籽粒形成乳熟期,需水量为359.15 mm,至9月下旬,玉米灌溉需水量下降;灌区作物需水量与气温呈正相关,与降水呈负相关,与风速和相对湿度相关性较小,气温、日照时数和相对湿度是影响作物需水量的主要因素.

The transpiration and evaporation,and irrigation water requirement change of winter wheat and maize were analyzed by using CROPWAT model. The correlation coefficient of crop water requirement with meteorological factors were calculated by using SPSS software. The results show that the average transpiration and evaporation of winter wheat was 634. 04 mm in the whole growth period,and the peak appeared in the middle of April to mid-May,the whole irrigation area had the same trend of transpiration and evaporation of winter wheat; the average transpiration and evaporation of maize was525. 22 mm,and the peak appeared in the middle of July to late August,the maximum was 535. 97 mm in Sanyuan and the minimum was 514. 68 mm in Fuping. Irrigation water requirement of winter wheat in the sowing-over wintering stage was minimum,and that in the turning green-jointing stage increased. Irrigation water requirement of corn in the tasseling-flowering stage was 133. 04 mm. July-August was for the grain formation-milk stage,water requirement was 359. 15 mm,until late September,corn irrigation water requirement dropped off. Crop water requirement was positively correlated with temperature,while it was negatively correlated with precipitation and it was less correlated with wind speed and relative humidity. Temperature,sunshine time and relative humidity are the main factors influencing the crop water requirement.