Contrasting responses of soil respiration and temperature sensitivity to land use types: Cropland vs. apple orchard on the Chinese Loess Plateau

Rui Wang; Qiqi Sun; Ying Wang; Wei Zheng; Lunguang Yao; Yaxian Hu; Shengli Guo

doi:10.1016/j.scitotenv.2017.11.290

Contrasting responses of soil respiration and temperature sensitivity to land use types: Cropland vs. apple orchard on the Chinese Loess Plateau

Sci Total Environ. 2018 Apr 15:621:425-433. doi: 10.1016/j.scitotenv.2017.11.290. Epub 2017 Nov 28.

Authors

Rui Wang¹, Qiqi Sun¹, Ying Wang², Wei Zheng², Lunguang Yao³, Yaxian Hu¹, Shengli Guo⁴

Affiliations

¹ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China.
² State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China.
³ Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China.
⁴ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China. Electronic address: slguo@ms.iswc.ac.cn.

PMID: 29190565
DOI: 10.1016/j.scitotenv.2017.11.290

Abstract

Land use plays an essential role in regional carbon cycling, potentially influencing the exchange rates of CO₂ flux between soil and the atmosphere in terrestrial ecosystems. Temperature sensitivity of soil respiration (Q₁₀), as an efficient parameter to reflect the possible feedback between the global carbon cycle and climate change, has been extensively studied. However, very few reports have assessed the difference in temperature sensitivity of soil respiration under different land use types. In this study, a three-year field experiment was conducted in cropland (winter wheat, Triticum aestivum L.) and apple orchard (Malus domestica Borkh) on the semi-arid Loess Plateau from 2011 to 2013. Soil respiration (measured using Li-Cor 8100), bacterial community structure (represented by 16S rRNA), soil enzyme activities, and soil physicochemical properties of surface soil were monitored. The average annual soil respiration rate in the apple orchard was 12% greater than that in the cropland (2.01 vs. 1.80μmolm^-2s^-1), despite that the average Q₁₀ values in the apple orchard was 15% lower than that in the cropland (ranging from 1.63 to 1.41). As to the differences among predominant phyla, Proteobacteria was 26% higher in the apple orchard than that in the cropland, whereas Actinobacteria and Acidobacteria were 18% and 36% lower in the apple orchard. The β-glucosidase and cellobiohydrolase activity were 15% (44.92 vs. 39.09nmolh^-1g^-1) and 22% greater (21.39 vs. 17.50nmolh^-1g^-1) in the apple orchard than that in the cropland. Compared to the cropland, the lower Q₁₀ values in the apple orchard resulted from the variations of bacterial community structure and β-glucosidase and cellobiohydrolase activity. In addition, the lower C: N ratios in the apple orchard (6.50 vs. 8.40) possibly also contributed to its lower Q₁₀ values. Our findings call for further studies to include the varying effects of land use types into consideration when applying Q₁₀ values to predict the potential CO₂ efflux feedbacks between terrestrial ecosystems and future climate scenarios.

Keywords: Bacterial communities; Land use type; Q(10) values; Soil enzyme activities.