Hydrologic balance, net primary productivity and water use efficiency of the introduced exotic Eucalyptus grandis x Eucalyptus urophylla plantation in south-western China
Hydrologic balance, net primary productivity and water use efficiency of the introduced exotic Eucalyptus grandis x Eucalyptus urophylla plantation in south-western China
复制标题
西南地区外来巨桉×尾叶桉人工林的水文平衡、净初级生产力及水分利用效率
DOI：
10.1093/jpe/rtz033
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发表时间：
2019
影响因子：
2.7
通讯作者：
Huang ZH
中科院分区：
文献类型：
--
作者：
Hu YT;Zhao P;Huang YQ;Zhu LW;Ni GY;Zhao XH;Huang ZH
目的：土地覆盖变化会破坏水分平衡，改变降水在地表径流、蒸散发和地下水补给中的分配。中国西南地区广泛种植的桉树具有潜在的水文影响。本研究旨在阐明引进的外来桉树grandis×Eucalyptus尾叶人工林的水文平衡特征，并评估其高生产力是由于高水分利用效率（WUE）还是大耗水量。方法建立400-m2的试验田。grandis×E。中国西南部的尾叶人工林。水分平衡组分包括林分蒸腾（Tr）、蒸散发（Et）和径流(R)，其计算方法如下：trt是基于树液流量测量估算的，ett是基于绿色植被覆盖度加权的地表蒸腾和蒸发的平均值，etr是通过安装的金属框架收集的。净初级生产力（NPP）由异速生长方程和胸径（DBH）增量测定得到。重要发现：年平均值为430±31 mm，年平均值为239±17 mm。年平均蒸散量占总蒸散量的56±8%。WUE （NPP/Tr）grandis×E。尾叶碱含量为3.3 ~ 3.9 mmol·mol−1。基于对两种城市用水效率的对比分析，grandis×E。尾叶树由于其高用水效率而具有高生产力，而不表现出浪费水的现象。水汽压亏缺和太阳总辐射（Rs）等气象因子是影响本站气温变化的关键因子。年地表径流、林冠截留分别占总降水量的7%、27-30%和16%，其余46-50%用于维持地下水补给和改变土壤储水量。径流系数越高（7.1%），表明e的能力越弱。grandis×E。尾叶林比天然林和受干扰较少的人工林蓄水量大。林下植被的种植和保护可以减少地表径流，对桉树人工林的保水能力产生有益的影响。
AimsLand cover changes can disrupt water balance and alter the partitioning of precipitation into surface runoff, evapotranspiration and groundwater recharge. The widely plantedEucalyptustrees in south-western China have the potential to bring about hydrologic impacts. Our research aims to elucidate the hydrologic balance characteristics of the introduced exoticEucalyptus grandis×Eucalyptus urophyllaplantation and to assess whether its high productivity results from high water use efficiency (WUE) or large water consumption.MethodsA 400-m2experimental plot was established in anE. grandis×E. urophyllaplantation in south-western China. Water balance components, including stand transpiration (Tr), evapotranspiration (Et) and runoff (R) were obtained as follows:Trwas estimated based on sap flow measurements,Etwas estimated as the average of surface transpiration and evaporation weighted by the fractional green vegetation cover using a modeling approach, andRwas collected using the installed metal frame. Net primary productivity (NPP) was obtained from allometric equation and annual diameter at breast height (DBH) increment determination.Important FindingsAnnualEtandTrwere 430 ± 31 and 239 ± 17 mm, respectively. AnnualTraccounts for 56 ± 8% of total evapotranspiration on average. WUE (NPP/Tr) of theE. grandis×E. urophyllawas estimated to be 3.3–3.9 mmol·mol−1. Based on the comparative analysis ofTrand WUE,E. grandis×E. urophyllahad a high productivity due to its high WUE without exhibiting prodigal water use. Meteorological factors including vapor pressure deficit and global solar radiation (Rs) were key factors regulatingEtandTrin our research site. Annual surface runoff,Etand canopy interception occupied 7%, 27–30% and 16% of total precipitation, while the remaining 46–50% of precipitation was used for sustaining groundwater recharge and altering soil water storage. The higher runoff coefficient (7.1%) indicated the weaker capability ofE. grandis×E. urophyllato reserve water resource than natural forests and less disturbed plantations. The planting and protection of understory vegetation may decrease the surface runoff and exert beneficial effects on water conservation capacity ofEucalyptusplantation.