College of Horticulture, Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China.
College of Natural Resources and Environment, Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, 712100, Shaanxi, China.
Environ Sci Pollut Res Int. 2020 Dec;27(35):43452-43465. doi: 10.1007/s11356-020-08526-5. Epub 2020 Apr 11.
The Loess Plateau is the largest apple cultivation region in the world. However, the role of rain-fed apple orchards as carbon sinks or sources, including the dynamic variation and influencing factors, are still unclear. In this study, the net ecosystem CO exchange (NEE) was monitored by an eddy covariance (EC) system in Loess Plateau apple orchards during 2016-2017. The results demonstrated that the annual NEE was higher in 2016 (- 698.0 g C m year) than in 2017 (- 554.0 g C m year). Particularly, the amount of orchard CO uptake was significantly greater in 2016 (- 772.0 g C m) than in 2017 (- 642.1 g C m) during the carbon sink period. This difference may be attributed to the higher NEE in 2016 compared to 2017 during the fast and slow growth periods. In addition, a higher daily NEE occurred to the higher air temperature (T), which promoted early sprouting in 2016 (- 3.91 g C m day) compared to 2017 (- 2.86 g C m day) during the fast growth period. The daily NEE in 2016 (- 2.59 g C m day) was remarkably higher than that in 2017 (- 1.41 g C m day) during the slow growth period, owing to the greater number of cloudy and rainy days and lower temperatures in 2017. Overall, the present study demonstrated the key role played by the amount of precipitation and temperature in regulating the NEE during the growth season and provided accurate quantitative information on the carbon budget in apple orchards. Graphical abstract.
黄土高原是世界上最大的苹果种植区。然而，雨养苹果园作为碳汇或碳源的作用，包括动态变化及其影响因素，仍不清楚。本研究通过涡度相关（EC）系统监测了黄土高原苹果园中 2016-2017 年的净生态系统 CO 交换（NEE）。结果表明，2016 年（-698.0 g C m year）的年 NEE 高于 2017 年（-554.0 g C m year）。特别是，在碳汇期，2016 年（-772.0 g C m）的果园 CO 吸收量明显大于 2017 年（-642.1 g C m）。这种差异可能是由于 2016 年快速生长期和缓慢生长期的 NEE 高于 2017 年。此外，较高的空气温度（T）导致较高的日 NEE，促进了 2016 年（-3.91 g C m day）的早期发芽，而 2017 年（-2.86 g C m day）的早期发芽则较低。2016 年（-2.59 g C m day）的日 NEE 明显高于 2017 年（-1.41 g C m day）的日 NEE，这主要是由于 2017 年多云和多雨日数较多，温度较低。总的来说，本研究表明，降水和温度在调节生长季节 NEE 方面起着关键作用，并为苹果园碳预算提供了准确的定量信息。
