| 黄土高原成龄苹果园生态系统CO2通量特征 |
| 摘要点击 2050 全文点击 684 投稿时间：2017-09-25 修订日期：2017-11-17 |
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| 中文关键词 黄土高原 苹果园 涡度相关 CO2通量 碳汇 |
| 英文关键词 Loess Plateau apple orchard eddy covariance CO2 flux carbon sink |
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| 中文摘要 |
| 黄土高原地区是中国和世界苹果（Malus demestica）集中连片栽培面积最大的区域，在生态环境改善中发挥了重要作用，然而关于黄土高原地区苹果园生态系统尺度上的碳通量研究很少.在本研究中，利用涡度相关技术对我国陕西黄土高原地区成龄苹果园生态系统的CO2通量和气象因素进行了观测.基于2016年1月到2016年12月的观测数据，定量分析了此苹果园净生态系统碳交换（NEE）、生态系统呼吸（Reco）和生态系统总初级生产力（GPP）不同时间尺度及主要气象因素的变化，探究了光合有效辐射（PAR）和不同层次土壤温度（Ts）、空气温度（Ta）对NEE的影响.结果表明，苹果园生态系统NEE月总量在非果树生长季12、1、2和3月为正值（表现为碳源），生长季（4~11月）均为负值（表现为碳汇），整体表现为强烈的碳汇.生长季NEE月平均日变化在8月出现最大吸收峰[-17.08 μmol·（m2·s）-1]，11月吸收峰最小[-4.47 μmol·（m2·s）-1]；在非生长季NEE的月平均日变化非常微弱，昼夜变化不明显.GPP、Reco和NEE日总量的最大值分别为11.12、5.04和-7.34 g·（m2·d）-1.GPP、Reco和NEE月总量的最大值分别为238.97、105.38和-144.44 g·（m2·月）-1，月GPP和NEE总量在5~8月保持相对稳定的高值.全年GPP、Reco和NEE分别为1223.2、525.2和-698.0 g·（m2·a）-1，表明我国黄土高原地区的成龄苹果园生态系统具有相对较高的固碳能力.夜间生态系统呼吸Reco.n与不同层次土壤温度、空气温度之间呈正相关关系，相关系数表现为Ts-5 cm > Ts-10 cm > Ta-4 m > Ta-8 m；光合有效辐射PAR可以解释白天NEE变化的80%以上. |
| 英文摘要 |
| Apples (Malus demestica) in the Loess Plateau region are grown in the largest apple orchards in the world and China, playing an important role in the improvement of the ecological environment. However, there is little research on the scale of the ecological system of the apple orchard in the Loess Plateau region. In this study, the CO2 flux of a mature apple orchard in the Loess Plateau region was observed using an eddy covariance technique in the Shannxi Province. Based on the observation data sets observed from January 2016 to December 2016, a quantitative analysis of the apple orchard net ecosystem exchange (NEE), ecosystem respiration (Reco), total ecosystem primary productivity (GPP) changes at different time scales, changes in main meteorological factors, the effects of soil temperature (Ts) and air temperature (Ta) at different levels, and PAR on NEE were discussed. The results showed that during the study period, the apple orchard ecosystem NEE monthly totals were positive (as a carbon source) in the non-growing season in December, January, February and March, were negative (a carbon sink) in the growing season from April to November, and functioned as a strong carbon sink year round. The maximum peak NEE (absolute value) monthly average daily change appeared in August[-17.08 μmol ·(m2 ·s)-1], and the smallest peak appeared in November[-4.47 μmol ·(m2 ·s)-1] during the growing season. The NEE monthly average daily change value during the non-growing season is very weak, though the change is not obvious. GPP, Reco, and NEE maximum daily total values were 11.12, 5.04, and -7.34 g ·(m2 ·d)-1, respectively. GPP, Reco, and NEE maximum monthly total values were 238.97, 105.38, and -144.44 g ·(m2 ·month)-1, respectively, as GPP and NEE maintained high cumulative values that were relatively stable from May through August. The annual GPP, Reco, and NEE were 1223.2, 525.2, and -698.0 g ·(m2 ·a)-1. The observations show that the mature apple orchard ecosystem in the Chinese Loess Plateau has a relatively high carbon sequestration capacity. Nighttime ecosystem respiration Reco.n was positively correlated with the soil temperature and air temperature at different levels, and the correlation coefficients were Ts-5 cm > Ts-10 cm > Ta-4 m > Ta-8 m, The photosynthetic active radiation (PAR) can explain more than 80% of the daytime NEE changes. |
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