膜下滴灌水量对谷子光合作用及水分利用效率影响

以"张杂谷5号"为试验材料,采用对比设计,在内蒙古阿拉善左旗巴彦浩特镇进行了田间试验,研究了北方干旱沙漠绿洲农区谷子全生育期光合作用的变化过程以及水分利用效率。结果表明:在试验条件下,膜下滴灌谷子不同生育期的日平均净光合速率、日平均蒸腾速率和日平均气孔导度呈"单峰"变化,在抽穗期达到峰值;日平均胞间CO_2浓度呈"V"形变化,在抽穗期达到谷值。不同生育阶段日平均叶片水分利用效率亦呈现"单峰"变化,抽穗期达到最大值。抽穗期净光合速率、蒸腾速率、气孔导度随日时间变化均呈现出"单峰"变化规律,随着灌溉定额的增加而增大;而胞间CO_2浓度则呈现出相反的变化规律,随着灌溉定额的增加而减少。通过综合分析得出,当地水资源缺乏情况下井灌区膜下滴灌较适宜的灌溉定额为3 750m~3/hm~2。

Effect of Drip Irrigation on Photosynthesis and Water Use Efficiency of Millet

Taking “Zhang zagu No.5”as the test material and using contrast design,the field experiment was carried out in Bayanha-ote town,Alashan Zuoqi,Inner Mongolia,to study the change process of photosynthesis and water use efficiency during the whole growth period of millet in north arid desert oasis area.The results showed that under the experimental conditions,the daily average net photosynthetic rate,daily average transpiration rate and stomatal conductance of millet under different growth stages were “sin-gle peak”,and reached the peak at heading stage;the CO2 concentration changed with “V”shape and reached the valley at heading stage;the average leaf water use efficiency of different growth stages also showed a “single peak”change and reached the maximum at heading stage;net photosynthetic rate,transpiration rate and stomatal conductance of the heading stage showed a “single peak”change law,which increased with the increase of irrigation quota,while the CO2 concentration showed the opposite change law. Through the comprehensive analysis,it is proposed that under the condition of lack of water resources in local Well irrigation area, the Suitable irrigation quota is 3 750 m3/hm2 .The study result has a reference value for water saving irrigation.