摘要
本研究以位于山西省右玉县农牧交错带的半干旱草地生态系统为研究对象,探究短期内不同水平的氮添加对半干旱草地生态系统CO_2交换的影响。试验设置8个梯度0、1、2、4、8、16、24和32 g N·m^(-2)(分别表示为N_0、N_1、N_2、N_4、N_8、N_(16)、N_(24)和N_(32))。采用静态箱法对草地净生态系统CO_2交换量(NEE)、生态系统呼吸(ER)进行测定,同时监测10 cm表层土壤温度和含水量。试验结果表明:短期氮添加(N_(32)除外)显著增加农牧交错带半干旱草地生态系统净碳交换,NEE、ER和生态系统总初级生产力(GEP)在整个生长季均随氮素添加水平的上升呈单峰型变化趋势,在N_(16)和N_(24)处理下的生态系统CO_2交换达到最高,而N_(32)显著降低了NEE;不同氮添加水平下,ER和GEP相对NEE更为敏感;表层(0～10 cm)土壤温度与含水量影响生态系统CO_2交换,表现为:土壤温度(10 cm)与ER呈显著正相关(R^2>0.1,P<0.05),表层(0～10 cm)土壤含水量与NEE和GEP分别呈显著正相关和显著负相关(R^2>0.1,P<0.05)。因此,短期不同水平氮添加增加了农牧交错带半干旱草地生态系统净碳吸收,对该地区草地生态系统碳的源/汇功能具有一定的参考意义。
This study investigated the short-term effects of different nitrogen (N) application rates in a semi-arid grassland ecosystem in an agro-pastoral ecotone in Youyu County, Shanxi Province, China. A randomized complete block experiment was set up with 8 nitrogen levels (0, 1, 2, 4, 8, 16, 24, and 32 g N·m^-2 , denoted N 0, N 1, N 2, N 4, N 8, N 16 , N 24 , N 32 , respectively), and 6 replicates (48 plots in total). Ecosystem net CO2 exchange (NEE) and ecosystem respiration (ER) under the different treatments were monitored using the static chamber method, with a fixed base for the portable chamber located in each plot before the start of the growing season, and chamber dimensions 50 cm×50 cm×50 cm. Gross ecosystem CO 2 capture was calculated from those primary data by difference, and was taken as gross ecosystem productivity (GEP). Nine measurements were undertaken at approximately two weekly intervals between June and September. Over this period, short-term N addition (except N 32 , which had a detrimental effect) significantly increased the net carbon uptake, with peak response seen in N 16 and N 24 treatments. The responses of ER and GEP to different N addition were more sensitive than NEE. There was a significant positive correlation between 10 cm soil temperature and ER ( R^2=0.319,P<0.0001), while the soil moisture for the upper 10 cm was significantly positively correlated with NEE ( R 2=0.420,P<0.0001) and was significantly negatively correlated with GEP ( R^2=0.202, P=0.0004). Therefore, short-term nitrogen addition increased the net carbon uptake of this semi-arid in the agro-pastoral ecotone, grassland ecosystem. Our study provides some reference data for grassland ecosystem carbon source/sink relationships in this region.
作者
董斅晓
薄元超
孙建平
张晓琳
王常慧
董宽虎
DONG Xiao-xiao;BO Yuan-chao;SUN Jian-ping;ZHANG Xiao-lin;WANG Chang-hui;DONG Kuan-hu(College of Animal Science and Technology,Shanxi Agricultural University,Taigu 030801,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China)
出处
《草业学报》
CSCD
北大核心
2019年第5期163-170,共8页
Acta Prataculturae Sinica
基金
国家重点研发计划子课题(2016YFC0500703)
国家自然科学基金面上项目(31572452
41573063)
植被与环境变化国家重点实验室研究群项目资助
关键词
氮梯度
农牧交错带
半干旱草地
生态系统CO2交换
nitrogen addition levels
agro-pastoral ecotone
semi-arid grassland
ecosystem CO 2 exchange
