西藏河谷农区灌水和中后期降雨对高产青稞耗水量与产量的影响

利用盆栽试验研究人工灌水及雨水对西藏河谷农区高产青稞耗水特性及产量的影响。试验材料为西藏青稞品种 ‘藏青 25’ ， 水分处理 8个： 全生育期正常水分、 轻度水分胁迫、 中度水分胁迫和重度水分胁迫理， 以及灌浆前正常水分、 轻度水分胁迫、 中度水分胁迫和重度水分胁迫处理后灌浆期以后雨水灌溉。试验结果表明， 土壤含水量越大， 青稞耗水量越大， 拔节期及灌浆期是青稞耗水量最大的时期。全生育期土壤水分胁迫会降低青稞的生物量及产量， 轻度水分胁迫、 中度水分胁迫、 重度水分胁迫与正常水分处理相比生物量下降了 29.9%、 41.7%、 47.6%， 单株产量下降了 15.8%、 43.7%、 57.2%。但前期水分胁迫灌浆期后雨水灌溉对青稞的生长受到促进， 生物量和产量增大， 与长期水分胁迫相比生物量增长了 13%、 75.8%、 128.1%、 157.8%， 产量增长了 42.8%、 84%、 201.6%和 269.5%。雨水灌溉在后期对青稞进行了补偿生长， 水分利用率也相应提高。因此， 在适当的水分胁迫 （50%~65%土壤田间持水量） 下， 利用雨水补充灌溉， 可以提高西藏高产青稞 ‘藏青25’ 的水分利用率， 增加产量。

Effect of Irrigation and Rainfall on Water Consumption Characteristics and Yield of High Yield Highland Barley in Tibet River Valley

This paper was to study the effect of irrigation and rainfall on water consumption characteristics and yield of high yield highland barley in Tibet river valley. In pots, highland barley-25 of Tibet was used as the test material to provide eight water stress treatments: normal water, slight water stress, middle water stress, and severe water stress in two environmental conditions (the whole growth period water stress and the rainwater irrigation after filling stage). Test results indicated that water consumption increased with soil water rise. The maximum consumption of water was at the joining stage and filling stage. And then, the results showed that under rainwater irrigation treatment, the more the soil moisture was, the more the water consumption was. The water stress in whole highland barely growth period reduced biomass and yield. Compared with that of normal water treatment, biomass of slight water stress, middle water stress and severe water stress treatment was decreased by 29.9% , 41.7% and 47.6% , respectively, and yield of the three treatments was decreased by 15.8%, 43.7% and 57.2%, respectively. But rainfall after filling stage was beneficial to biomass and yield of highland barely. Compared with water stress on whole growth period, the biomass and yield of rainfall treatments after the filling stage were increased by 13%, 75.8%, 128.1%, 157.8% and 42.8%, 84%, 201.6%, 269.5% . The results indicated that biomass and yield of rainwater irrigation after the filling stage had compensatory effect for highland barley growth under water stress, and could improve the water use efficiency. Therefore, properly rainwater usage is beneficial to the increase of yield and water use efficiency of Tibet highland barley-25 under water stress.