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Pedosphere 27(5): 846--855, 2017
ISSN 1002-0160/CN 32-1315/P
©2017 Soil Science Society of China
Published by Elsevier B.V. and Science Press

Effects of elevated co₂ and drought on plant physiology, soil carbon and soil enzyme activities

WANG Yuhui¹, YAN Denghua², WANG Junfeng¹, DING Yi¹, SONG Xinshan¹

¹College of Environmental Science and Engineering, Donghua University, Shanghai 201620 (China)
2China Institute of Water Resources and Hydropower Research, Beijing 100038 (China)

ABSTRACT

Global climate models have indicated high probability of drought occurrences in the coming future decades due to the impacts of climate change caused by a mass release of CO₂. Thus, climate change regarding elevated ambient CO₂ and drought may consequently affect the growth of crops. In this study, plant physiology, soil carbon, and soil enzyme activities were measured to investigate the impacts of elevated CO₂ and drought stress on a Stagnic Anthrosol planted with soybean (Glycine max). Treatments of two CO₂ levels, three soil moisture levels, and two soil cover types were established. The results indicated that elevated CO₂ and drought stress significantly affected plant physiology. The inhibition of plant physiology by drought stress was mediated via prompted photosynthesis and water use efficiency under elevated CO₂ conditions. Elevated CO₂ resulted in a longer retention time of dissolved organic carbon (DOC) in soil, probably by improving the soil water effectiveness for organic decomposition and mineralization. Drought stress significantly decreased C:N ratio and microbial biomass carbon (MBC), but the interactive effects of drought stress and CO₂ on them were not significant. Elevated CO₂ induced an increase in invertase and catalase activities through stimulated plant root exudation. These results suggested that drought stress had significant negative impacts on plant physiology, soil carbon, and soil enzyme activities, whereas elevated CO₂ and plant physiological feedbacks indirectly ameliorated these impacts.

Key Words: catalase, drought stress, invertase, plant growth, plant-soil-microbe system, soil C:N ratio, water use efficiency

Citation: Wang, Y., Yan, D., Wang, J., Ding, Y. and Song, X. 2017. Effects of elevated co₂ and drought on plant physiology, soil carbon and soil enzyme activities. Pedosphere. 27(5): 846-855.

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