塔里木灌区棉田蒸散与棵间蒸发变化规律

为了给塔里木灌区棉花合理灌溉提供科学理论依据,根据新疆阿克苏农田生态系统国家野外科学观测研究站监测的地面沟灌棉田土壤水分、降水量、灌水量等资料,采用水量平衡原理计算了棉田蒸散量,采用自制的Micro-Lysimeters测定了棉田棵间蒸发,分析了棉田蒸散和棵间蒸发的变化规律及其影响因子,结果表明,棉田蒸散强度与棵间蒸发强度从苗期、蕾期、花铃期逐渐增大,到花铃期达到最大,吐絮期、收获期逐渐减小;棵间蒸发占棉田蒸散量的比例从苗期、蕾期、花铃期逐渐减小,到花铃期达到最小,吐絮期、收获期又逐渐增大,棉花生育期内棵间蒸发占蒸散量的比例为16.49％.棉花相对棵间蒸发强度与表层土壤含水量关系密切,随着表层土壤含水量的增大相对棵间蒸发强度增强.

The changing law of the diurnal evapotranspiration and soil evaporation in cotton field of Tarim irrigation area

In order to provide a scientific theoretical basis for reasonable irrigation of cotton in Tarim irrigation area, and based on soil moisture, precipitation, irrigation and other data observed at Aksu National Field Research Station of Agro-ecosystem in Xinjiang, evapotranspiration is calculated by using water balance method, evaporation is monitored by using self-made Micro-lysimeters, and the changing law and affecting factors are analyzed. The results show that the in-tensity of cotton evapotranspiration and evaporation increases gradually in seedling, squaring, flowering and bolling stages, reaching its maximum in flowering and bolling stages, and then decreases gradually in boling opening and har-vesting stages. The ratio of evaporation to evapotranspiration of cotton decreases gradually in seeding, squaring and flow-ering and bolling stages, reaching its minimum in flowering and bolling stages,then increasesgradually in boll opening and harvesting stages. All through these stages, the ratio of evaporation to evapotranspiration is about 16.49%. The relative evaporation intensity of cotton shows close relation to surface soil moisture, and it increases with the surface soil moisture.