Linking diffuse radiation and ecosystem productivity of a desert steppe ecosystem

PeerJ

article

Cheng Li¹  Xin Jia¹  Jingyong Ma¹  Peng Liu¹  Ruizhi Yang¹  Yujie Bai¹  Muhammad Hayat¹  Jinglan Liu³  Tianshan Zha¹ 

[1] Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University;Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University;School of Ecology and Nature Conservation, Beijing Forestry University

关键词: Diffuse radiation;    Clearness index;    Gross ecosystem production;    Desert steppe ecosystem;   

DOI  :  10.7717/peerj.9043

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Radiation components have distinct effects on photosynthesis. In the desert steppe ecosystem, the influence of diffuse radiation on carbon fixation has not been thoroughly explored. We examined this diffusion and its effect on ecosystem productivity was examined during the growing season from 2014 to 2015 on the basis of eddy covariance measurements of CO2 exchange in a desert steppe ecosystem in northwest China. Our results indicated that the gross ecosystem production (GEP) and diffuse photosynthetically active radiation (PARdif) peaked when the clearness index (CI) was around 0.5. The maximum canopy photosynthesis (Pmax) under cloudy skies (CI < 0.7) was 23.7% greater than under clear skies (CI ≥ 0.7). When the skies became cloudy in the desert steppe ecosystem, PARdif had a greater effect on GEP. Additionally, lower vapor pressure deficits (VPD ≤ 1 kPa), lower air temperatures (Ta ≤ 20 °C), and non-stressed water conditions (REW ≥ 0.4) were more conducive for enhanced ecosystem photosynthesis under cloudy skies than under clear skies. This may be due to the comprehensive effects of VPD and Ta on stomatal conductance. We concluded that cloudiness can influence diffuse radiation components and that diffuse radiation can increase the ecosystem production of desert steppe ecosystems in northwest China.

【 授权许可】

CC BY