摘要
为揭示不同退耕林植被水分利用效率差异及其关键影响因素,以黄土丘陵区恢复20年的山杏、沙棘、刺槐、油松、杨树、刺槐山桃混交林为研究对象,采用气体交换法测定了不同退耕林植被瞬时水分利用效率,并测定了其相关影响因素指标。结果表明:不同退耕林之间水分利用效率均存在显著差异,最高为油松,达到了6.39μmolCO_(2)/mmolH_(2)O,其次为混交林的刺槐为5.89μmolCO_(2)/mmolH_(2)O,最低为山杏,两者分别比山杏高出1.83倍和1.61倍;并且刺槐混交林与刺槐纯林的水分利用效率相比提高了38.0%。相关分析结果表明,水分利用效率与植被因子的气孔导度、蒸腾速率、胞间CO_(2)浓度、叶片含水率呈显著负相关;与土壤因子中的有机碳、全氮、可溶性有机碳、饱和导水率极显著正相关,与土壤pH显著正相关。逐步回归分析可以得出,植物因素对水分利用效率的影响强于土壤因素,其中植物叶片气孔导度、叶绿素SPAD值和土壤全氮含量、饱和导水率是对水分利用效率影响较强的植被与土壤因素。综上所述,本研究中油松林地的水分利用效率最高,山杏最低,并且气孔导度、叶绿素含量、土壤全氮含量和饱和导水率是影响水分利用效率的主要因素,这为认知退耕还林植被水资源利用能力以及其影响机制提供了科学依据。
In order to reveal the difference and key influencing factors of water use efficiency of different returning farmland to forest vegetation,in this study,the forests of Armeniaca sibiricat,Hippophae rhamnoides,Pinus tabulaeformis,Populus simonii,Robinia pseudoacacia and Robinia pseudoacacia Amygdalus davidiana mixed forest that had been restored for 20 years in loess hilly region were taken as research objects,the gas exchange method was used to determine the instantaneous water use efficiency of different forest vegetation,and the related influencing factors were measured.The results showed that there were extremely significant differences in water use efficiency between different forest tree species.The highest was Pinus tabulaeformis(6.39μmolCO_(2)/mmolH_(2) O),followed by Robinia pseudoacacia mixed forest(5.89μmolCO_(2)/mmolH_(2) O),and the lowest was Armeniaca sibiricat.The first two were 1.83 and 1.61 times higher than the Armeniaca sibiricat respectively.Compared with the Robinia pseudoacacia forest,the water use efficiency of Robinia pseudoacacia mixed forest was increased by 38.0%.Correlation analysis showed that WUE had a significant negative correlation with Gs,Tr,Ci,RWC values of vegetation factors.It had a very significant positive correlation with soil factors SOC,TN,DOC,Ks,and had a significant positive correlation with pH.Stepwise regression analysis showed that plant factors had a stronger influence on WUE than soil factors,among which stomatal conductance,chlorophyll SPAD value,total nitrogen content and saturated water conductance of plant and soil had stronger influence on WUE.In summary,the water use efficiency of Pinus tabulaeformis forest land was the highest,while that of Prunus arundinacea was the weakest.Stomatal conductance,chlorophyll content,total soil nitrogen content and saturated hydraulic conductivity were the main factors affecting water use efficiency in this study.This study provided a scientific basis for the cognition of water resources utilization capacity and its influenci
作者
吴冠宇
WU Guan-yu(Water Conservancy and Hydropower Engineering Consulting Center of Shaanxi Province,Xi’an 710000,China)
出处
《节水灌溉》
北大核心
2021年第10期78-83,88,共7页
Water Saving Irrigation
基金
陕西省水利科技计划项目(2018slkj-7)。
关键词
水分利用效率
光合特性
土壤理化性质
退耕还林
黄土丘陵区
water use efficiency
photosynthetic characteristics
soil physical and chemical properties
returning farmland to forest
Loess hilly region
