Purpose Soil respiration (Rs) constitutes the second greatest carbon transfer from land-based ecosystems to the atmosphere, and its behavior has become more complex under climate change and anthropogenic disturbance, however, the regulatory mechanisms are still uncertain. Methods In this study, a 6-year field experiment was used to monitor Rs dynamics and its variation under grazing (GT), precipitation reduction (RT), and fenced (FT) treatments. Relationships with environmental factors were also studied in a sandy Pinus sylvestris var. mongolica plantation of the Three-North Shelterbelt Project in China. Results Rs changed differently at the daily, monthly and interannual timescales. The daily Rs varied insignificantly from day to night among the three treatments, but the average daily Rs of the GT plot was significantly greater than that of the FT plot. In all three plot types, monthly Rs presented an inverse ‘U’ shape from January to December, and the highest values ranged from 6.99 µmol·m− 2·s− 1 to 10.22 µmol·m− 2·s− 1 in July, while the lowest values were only 0.13 µmol·m− 2·s− 1 to 0.20 µmol·m− 2·s− 1 in January and December. Compared to the FT plot, both the GT and RT plots presented lower Rs during the nongrowing season but higher Rs during the growing season. The annual Rs also exhibited similar trends from 2016 to 2021 among the GT, RT and FT plots, and its average values decreased in the sequence of RT, GT and FT. Soil temperature was positively and significantly correlated with Rs at the daily, monthly, and annual time scales, whereas soil moisture was positively correlated with Rs only at the daily timescale under these three treatments. In addition, the temperature sensitivity of soil organic carbon decomposition (Q10) in both the RT and GT plots increased, especially Q10 of the RT plot, which was significantly greater than that of the FT plot. Conclusion Compared with the fenced treatment, the grazing treatment increased Rs and its variability on the daily, monthly and annual timescales, whereas the reduction in precipitation increased Rs and its variability only on the monthly and annual timescales. However, both treatments increased the temperature sensitivity of soil organic carbon decomposition, which implies that forest soil may release more CO2 under human disturbance and climate change scenarios (increased temperature and decreased precipitation) in the future in this sandy region.

Scale-dependent divergent response of soil respiration and its variation under grazing and reduced precipitation in a sandy Pinus sylvestris var. mongolica plantation

期刊论文
发表日期：

2026年5月28日

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Zi Li,
Xu Han,
Hengming Zhang,
Jiang Zhao,
Xiang Li,
Guochuang Zhang,
Yawei Wei,
Shengjin Qin

摘要

Purpose

Soil respiration (Rs) constitutes the second greatest carbon transfer from land-based ecosystems to the atmosphere, and its behavior has become more complex under climate change and anthropogenic disturbance, however, the regulatory mechanisms are still uncertain.

Methods

In this study, a 6-year field experiment was used to monitor Rs dynamics and its variation under grazing (GT), precipitation reduction (RT), and fenced (FT) treatments. Relationships with environmental factors were also studied in a sandy Pinus sylvestris var. mongolica plantation of the Three-North Shelterbelt Project in China.

Results

Rs changed differently at the daily, monthly and interannual timescales. The daily Rs varied insignificantly from day to night among the three treatments, but the average daily Rs of the GT plot was significantly greater than that of the FT plot. In all three plot types, monthly Rs presented an inverse ‘U’ shape from January to December, and the highest values ranged from 6.99 µmol·m^− 2·s^− 1 to 10.22 µmol·m^− 2·s^− 1 in July, while the lowest values were only 0.13 µmol·m^− 2·s^− 1 to 0.20 µmol·m^− 2·s^− 1 in January and December. Compared to the FT plot, both the GT and RT plots presented lower Rs during the nongrowing season but higher Rs during the growing season. The annual Rs also exhibited similar trends from 2016 to 2021 among the GT, RT and FT plots, and its average values decreased in the sequence of RT, GT and FT. Soil temperature was positively and significantly correlated with Rs at the daily, monthly, and annual time scales, whereas soil moisture was positively correlated with Rs only at the daily timescale under these three treatments. In addition, the temperature sensitivity of soil organic carbon decomposition (Q₁₀) in both the RT and GT plots increased, especially Q₁₀ of the RT plot, which was significantly greater than that of the FT plot.

Conclusion

Compared with the fenced treatment, the grazing treatment increased Rs and its variability on the daily, monthly and annual timescales, whereas the reduction in precipitation increased Rs and its variability only on the monthly and annual timescales. However, both treatments increased the temperature sensitivity of soil organic carbon decomposition, which implies that forest soil may release more CO₂ under human disturbance and climate change scenarios (increased temperature and decreased precipitation) in the future in this sandy region.