金丝小枣蒸散和作物系数变化规律研究

Daily Transpiration,Evaporation and Crop coefficient of Ziziphus Jujube

采用Probe12植物茎液流计和小型蒸发器分别测定了金丝小枣生长期间的日蒸腾和棵间蒸发。蒸腾存在日变化和季节性变化,果实膨大期蒸腾的日变化呈双峰曲线,萌芽展叶期、开花坐果期、果实成熟期和落叶期的日变化呈单峰曲线;萌芽展叶期、开花坐果期、果实膨大期、果实成熟期和落叶期的蒸腾量分别占生长季总耗水量的12.2%、16.5%、48.1%、13.2%、10.1%,金丝小枣生育期总蒸腾量346.8 mm,棵间蒸发231.7 mm,总蒸散578.5mm;棵间蒸发占总蒸散量的40.1%。枣树的作物系数随生育期变化从前期的0.27,到中期0.92,后期0.71,作物系数与冠层覆盖度呈显著正相关关系,决定系数为R2=0.758 6(P<0.01)。

Thermal Dissipation Sap Wood Flow Velocity Probe （Probe 12） and micro-lysimeter were used to measure daily transpiration （T） and soil evaporation（E） of Ziziphus Jujuba trees. Results showed that T had daily change and seasonal change patterns： during fruit enlargement period, T showed a bimodal curve change~ while during budding, leaf-expansion, flowering, fruit bearing and defoliation periods, T dis- played an unimodal curve change. Total transpiration was 346.8 mm during the whole growing period of Jujube, in which budding to leaf- expansion took up 12. 2%, 16.5% from leaf-expansion to flowering, 48.1G during fruit enlargement period, 13.2G during fruit mature period and 10.1% during defoliation period. Total soil evaporation was 231.7 ram. Total water consumption （transpiration and evaporation） during the whole growth period of Jujube was 578.5 mm, in which soil evaporation took up 40.1~ and crop transpiration took up 59.9%. Crop coefficient varied from 0. 27（initial growth stage）, 0.92（mid-sea- son growth stage） to 0.71（late season growth stage） and it was positively correlated with the canopy cov- erage （R2=0. 758 6） （P〈0. 01）.