A comprehensive meta-analysis of the impacts of intensified drought and elevated CO2 on forage growth

Wanlu Liu; Lulu Liu; Rui Yan; Jiangbo Gao; Shaohong Wu; Yanhua Liu

doi:10.1016/j.jenvman.2022.116885

A comprehensive meta-analysis of the impacts of intensified drought and elevated CO₂ on forage growth

J Environ Manage. 2023 Feb 1:327:116885. doi: 10.1016/j.jenvman.2022.116885. Epub 2022 Nov 28.

Authors

Wanlu Liu¹, Lulu Liu², Rui Yan³, Jiangbo Gao⁴, Shaohong Wu⁵, Yanhua Liu⁶

Affiliations

¹ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: liuwl.18b@igsnrr.ac.cn.
² Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, 100101, China. Electronic address: liull.16b@igsnrr.ac.cn.
³ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: yanr.20b@igsnrr.ac.cn.
⁴ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, 100101, China. Electronic address: gaojiangbo@igsnrr.ac.cn.
⁵ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: wush@igsnrr.ac.cn.
⁶ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: liuyh@most.gov.cn.

PMID: 36455442
DOI: 10.1016/j.jenvman.2022.116885

Abstract

Forage crops are used worldwide as key feed sources for dairy systems. However, their productivity and quality are limited due to intensified drought events, elevated carbon dioxide (CO₂), and their interaction with climate change, with consequences for the security of animal husbandry and the agricultural economy. Although studies have quantified the impacts of such stresses on forage growth, these impacts have been less systematically investigated in a global context due to differences among various forage groups, regional microclimates, and environmental factors. Herein we employed nine forage growth-related variables involving three perspectives, i.e., photosynthetic parameters, production, and quality, from research articles published between 1990 and 2021 via a meta-analysis. A linear mixed-effect model was then used to explore the quantitative relationship between these factors in a restricted dataset. Decreasing trends in all four photosynthetic parameters were detected across different eco-geographical regions with increasing drought stress. The maximum decrease in DMY occurred in the Mediterranean, with 52.8% under drought conditions. Globally, eCO₂ significantly increased photosynthetic rate (P_n) and instantaneous water use efficiency (WUE_i) by 40.8% and 62.1%, respectively, which also had positive effects on forage dry matter yield (DMY) (+25.1%), especially for forage in Northern Europe. However, this stress would significantly decrease forage quality by decreasing crude protein (CP) (-19.7%) and nitrogen content (N content) (-13.5%). These negative impacts would be aggravated under the co-occurrence of drought and eCO₂, including a significant increase in WUE_i (+111.1%) and a decrease in DMY (-12.3%). Gramineae showed a more sensitive response to drought stress in photosynthetic parameters and DMY than Leguminosae, but the latter exhibited a better response in photosynthetic parameters and production under eCO₂. Our analysis provides a consensus concerning how the growth parameters of forage have changed under environmental stresses.

Keywords: Drought stress; Elevated CO(2) concentration; Forage growth-related variables; Linear mixed-effects model; Meta-analysis.

Publication types

Meta-Analysis

MeSH terms

Animals
Carbon Dioxide* / metabolism
Droughts*
Photosynthesis / physiology
Poaceae / metabolism
Water

Substances

Carbon Dioxide
Water