青藏高原金露梅灌丛草甸水分利用效率长期变化特征  

Spatiotemporal variations in the water use characteristics and efficiency of Potentilla fruticosa shrubs found in the Qinghai Tibet Plateau

作　　者：王云英 裴薇薇 辛莹 郭小伟[1] 杜岩功[1] WANG Yunying;PEI Weiwei;XIN Ying;GUO Xiaowei;DU Yangong(Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,Qinghai,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院西北高原生物研究所,青海西宁810001 [2]中国科学院大学,北京100049

出　　处：《草业科学》2021年第9期1671-1682,共12页Pratacultural Science

基　　金：科技部基础调查专项(2017FY100202);国家自然科学基金面上项目(31770532)。

摘　　要：解析高寒草甸水分利用效率连续变化特征及其影响因素,对于提升高寒草甸水分利用效率具有重要作用。本研究基于2003–2010年青海海北金露梅(Potentilla fruticosa)灌丛草甸连续8年间总初级生产力(gross primary productivity,GPP)和借助于潜热通量(latent heat flux,LE)和蒸发潜热(λ)计算实际蒸散量,进而计算出8年间水分利用效率值,并探讨了其对气象因子的响应特征,结果表明:1)年际尺度上,8年间总初级生产力、蒸散量和水分利用效率分别以每年98.55 g·m^(−2)、40.15 mm和138.70 g·(m^(2)·mm)^(−1)的趋势上升;季节尺度上,总初级生产力、蒸散量和水分利用效率均在7月份达到最大值,1月份呈现最小值。2)年均温度、相对湿度和净辐射对全年水分利用效率相对贡献率均最高,三者能解释73.50%的全年水分利用效率变异。光合有效辐射、空气温度和相对湿度3个环境因子在生长季尺度上相对贡献率总值为74.14%。在全年和生长季尺度上,年均气温和光合有效辐射贡献率较高,分别为43.09%和30.79%。相关性分析结果显示,相对湿度是影响水分利用效率的主要因子,全年尺度上还有年均气温和饱和水汽压差,生长季尺度上主要影响因素还包括光合有效辐射和净辐射。研究结果对于明晰金露梅灌丛草甸水分利用效率调控机制具有重要意义。Analysis of the characteristic changes in water use efficiency in alpine meadows and its influencing factors plays an important role in improving the water use efficiency of these alpine meadows.Our study used gross primary productivity(GPP)and evapotranspiration as calculated by the latent heat flux(LE)and the latent heat of evaporation(latent heat of evaporation,λ)to evaluate the water dynamics of Potentilla fruticosa shrub meadows in Haibei,Qinghai Province between 2003 and 2010.The water use efficiency(WUE)of these shrub meadows was evaluated across eight consecutive years,allowing for a robust evaluation of their response to meteorological factors.Our results showed the following:1)On an interannual scale,the gross primary productivity,evapotranspiration,and water use efficiency increased at an annual rate of 98.55 g·m^(−2),40.15 mm,and 138.70 g·(m^(2)·mm)^(−1),respectively.While gross primary productivity,evapotranspiration,and water use efficiency all reached their maximum in July and their minimum in January when evaluated on a seasonal scale.2)The annual average temperature,relative humidity,and net radiation have the highest relative contribution to the annual water use efficiency,and these factors can explain up to 73.50%of the variation in the annual water use efficiency values.The following three environmental factors:photosynthetically active radiation,air temperature,and relative humidity contribute as much as 74.14%to the values on the growth season scale.The annual average temperature and photosynthetically active radiation rates are both relatively important contributing factors to both the annual and growing season scales,with these values accounting for up to 43.09%and 30.79%of the total,respectively.Correlation analysis revealed that relative humidity was the main factor affecting water use efficiency.Annual average temperature and vapor pressure deficit also exerted some effect on the annual scale values under these conditions.The main influencing factors for the growing season scale

关 键 词：金露梅灌丛 青藏高原 水分利用效率 饱和水气压差 净辐射 光合有效辐射 年均气温 

分 类 号：S812[农业科学—草业科学]