喷灌冬小麦耗水与棵间蒸发试验

 【目的】研究喷灌条件下冬小麦的耗水规律,指导田间灌溉实践。【方法】在北京地区2005－2008年3个冬小麦生长季节,开展不同喷灌水量条件下土壤水分分布、冬小麦耗水和棵间蒸发特性的试验研究,并分析影响棵间蒸发的主要因素。【结果】喷灌条件下,0～40 cm土层土壤的含水量受灌溉水量影响较明显,耗水量随着灌水量增加而增加。返青至收获期,冬小麦棵间蒸发为耗水量的25%左右,棵间蒸发随着灌水量的增大而增大,但棵间累积蒸发与作物耗水量之比随之而下降。【结论】适当加大灌水定额,减少灌溉次数,可在一定程度上抑制土壤的无效蒸发,提高灌溉水的利用率。

Field Experiments on Evaporation and Evapotranspiration of Winter Wheat Under Sprinkler Irrigation

【Objective】 The objective of the experiment was to evaluate the evapotranspiration (ET) of winter wheat under sprinkler irrigation in Beijing area, which is useful to the field sprinkler irrigation management practices of winter wheat. 【Method】Field experiments were conducted in 2005-2008 growing seasons in an experimental station with different irrigation depths. 【Result】 Results indicated that variation of soil water content occurred within 0-40 cm soil layer. The seasonal ET of winter wheat generally increased with the increasing of irrigation amount, while the seasonal usage of soil water had a negative relationship with irrigation amount. Soil evaporation was about 25% of winter wheat ET during the period from reviving to maturity. Soil evaporation increased while the proportion of soil evaporation to ET decreased as the increase of irrigation amount. 【Conclusion】 Sprinkler irrigation scheduling with a relatively large irrigation quota and low irrigation frequency can reduce soil evaporation and promote irrigation water use efficiency.