摘要
研究不同土壤水分阈值灌溉下毛白杨(Populustomentosa)生长季蒸腾与环境因子的关系,对于科学制定毛白杨高效水分管理策略至关重要。该研究以毛白杨人工林为研究对象,设置不同灌溉处理:充分灌溉(DF,当滴头正下方20cm处的土壤水势达到–18 kPa时灌溉)、控水灌溉(DC,当滴头正下方20 cm处的土壤水势达到–45 kPa时灌溉)和无灌溉(CK,空白对照)。采用热扩散技术,对毛白杨生长季树干液流通量进行连续观测,并同步监测太阳辐射(SR)、空气温度(Ta)、空气湿度(RH)、土壤体积含水率(SWC)和风速(WS)等环境因子。结果显示:1)不同灌溉处理下毛白杨树干液流通量日变化趋势相似,呈现单峰型,并存在显著的夜间液流活动。灌溉处理不会影响树干液流的启动时间,但会造成树干液流峰值时间出现差异,充分灌溉会使液流峰值到达时间提前。灌溉会增大毛白杨蒸腾量,毛白杨的蒸腾量随着土壤水分灌溉阈值的减小而增大。2)毛白杨树干液流密度与SR和空气水汽压亏缺(VPD)存在明显的时滞现象,树干液流通量变化提前于VPD,而滞后于SR。不同灌溉处理对时滞现象无显著影响。3) 3个处理下,蒸腾与VPD、SR及SWC具有显著正相关关系,与风速具有显著负相关关系,且对气象因子的响应程度不同。综上所述,灌溉能够有效调节人工林水分生理对环境因子的适应过程,但增加灌溉未必会造成蒸腾相应增加。根据林分蒸腾需水和自然降雨的关系,生长季前期(该研究为4–7月)进行灌溉有利于毛白杨人工林水分生理活动的进行。
Aims Understanding the relationship between transpiration and environmental factors is critical to the establishment of efficient irrigation strategies for Populus tomentosa.Therefore,we studied transpiration and environmental responses of P.tomentosa under varied irrigation treatments.Methods This study was carried out at the triploid P.tomentosa plantation in Gaotang County,Shandong Province.The irrigation treatments were set as full irrigation(DF,irrigated when the soil water potential at 20 cm directly below the dripper reached–18 kPa),water-controlled irrigation(DC,irrigated when the soil water potential at 20 cm directly below the dripper reached–45 kPa)and no irrigation(CK,blank control).Thermal dissipation probes(TDP)were used to observe the continuous sap flow of P.tomentosa during the growing season of 2019.The environmental factors were simultaneously monitored,including solar radiation(SR),air temperature(Ta),soil moisture content(SWC)and wind speed(WS).Important findings 1)The trend of the diurnal sap flow variation of P.tomentosa was similar among the contrasting treatments,showing a single-peak curve,and there was significant sap flow at night.Irrigation treatments did not influence the start of stem sap flow but caused differences in the timing of the stem peak flow.The peak flow arrived earlier in the DF treatment than in other treatments.Irrigation increased the transpiration of P.tomentosa.However,the transpiration would increase with the decrease of soil moisture deficit threshold of irrigation,namely transpiration of DC followed by DF and CK in sequence.2)There was significant time-lag between the sap flow and SR and VPD.The sap flow was ahead of the VPD and lagged behind the SR.Irrigation treatments have no significant effect on the time-lag effect between the sap flow and environmental factors.3)Under the three treatments,transpiration has a significantly positive correlation with VPD,SR and SWC,and negatively correlated with wind speed.The transpiration responses to the environmental factors varied among irrigation treatments.In summary,irrigation could effectively mediate the hydraulic adaptation of plantation trees to the environment factors.However,increased irrigation does not necessarily lead to transpiration enhancement.Based on the differences of stand transpiration and natural rainfall,irrigation during the beginning of the growing season(April to July in this study)would benefit the hydraulic physiological activity of the P.tomentosa plantation.
作者
赵文芹
席本野
刘金强
刘洋
邹松言
宋午椰
陈立欣
ZHAO Wen-Qin;XI Ben-Ye;LIU Jin-Qiang;LIU Yang;ZOU Song-Yan;SONG Wu-Ye;CHEN Li-Xin(College of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Ministry of Education Key Laboratory of Silviculture and Conservation,Beijing Forestry University,Beijing 100083,China)
出处
《植物生态学报》
CAS
CSCD
北大核心
2021年第4期370-382,共13页
Chinese Journal of Plant Ecology
基金
国家科技重大专项(2018zx07101005-03-020)
国家自然科学基金(32001304、31872702和4197070351)。
关键词
环境因子
灌溉
树干液流通量
林分蒸腾
environmental factor
irrigation
sap flow density
stand transpiration