黄土高原刺槐人工林地表凋落物对土壤呼吸的贡献  

Aboveground litter contribution to soil respiration in a black locust plantation in the Loess Plateau

作　　者：周小刚[1,2] 郭胜利[1,3] 车升国[4] 张芳[3] 邹俊亮[3] 张彦军[3] 南雅芳[3] 李泽[3] 蒲辉 

机构地区：[1]中国科学院水利部水土保持研究所 黄土高原土壤侵蚀与旱地农业国家重点实验室,杨凌712100 [2]中国科学院研究生院,北京100049 [3]西北农林科技大学,陕西杨凌712100 [4]中国农业科学院农业资源与农业区划研究所,北京100081 [5]昆明龙慧工程设计咨询有限公水保二部,昆明650000

出　　处：《生态学报》2012年第7期2150-2157,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金资助(41071338)

摘　　要：于黄土高原沟壑区王东沟小流域26年刺槐人工林(Robinia pseudoacacia)中,设置对照(CK)、去除凋落物(no litter,NL)和倍增凋落物(double litter,DL)3个处理,利用Li-8100系统测定各处理的土壤呼吸速率。结果表明,添加或去除凋落物显著影响土壤呼吸(P=0.091-0.099),与对照(CK)的土壤呼吸速率(3.23μmol m-2s-1)相比,添加凋落物(DL)使土壤呼吸速率增加26%,去除凋落物(NL)使土壤呼吸速率减少22%。NL、CK和DL的累积土壤呼吸分别为631、787和973 g C m-2a-1。各处理土壤呼吸速率与土壤温度呈显著的指数关系(R2=0.81-0.90,P<0.0001),但与土壤水分的关系不明显。NL、CK和DL的Q10依次为1.92、2.29和2.31。地表凋落物对土壤呼吸年平均贡献量为20%。相关性分析表明,各测定日地表凋落物贡献与土壤温度(r=0.54,P<0.05)或土壤水分关系显著(r=0.68,P<0.05)。刺槐人工林地表凋落物的输入量为213 g C m-2a-1,大于凋落物引起的呼吸量156 g C m-2a-1。在黄土区通过植被恢复治理水土流失过程中,随着地表凋落物的积累,林地生态系统的碳汇功能将逐步得到加强。Aboveground litter is a key factor for carbon sequestration in territorial ecosystems as well as soil conservation in erosion-derived,degraded areas.On the Loess Plateau,understanding aboveground litter contribution to soil respiration（LC） enhances the investigation of soil C dynamics as a consequence of litter accumulation accompanying vegetation restoration.Aboveground litter manipulation was carried out in a 26-year-old black locust plantation（Robinia pseudoacacia） in the Wangdong catchment in the gully region of the Loess Plateau.Litter treatments consisted of no litter（NL,aboveground litter excluded from plots）,control（CK,normal litter inputs allowed）,and double litter（DL,aboveground litter doubled by adding litter removed from NL plots）.There were three plots in each treatment,and the plot size was 1.5 m×1.5 m.Three polyvinyl chloride（PVC） collars were installed along the diagonal in each plot.Soil respiration rates（Rs） were measured approximately once every two weeks in 2009 decreasing to once every four weeks in 2010 during the period of April to October in both years using a Li-8100 closed chamber system（Li-COR,Lincoln,NE,USA）.In total,Rs was measured on 19 occasions during the two-year period.Concurrent with each respiration measurement,soil temperature at the 5-cm depth was measured using a Li-Cor thermocouple while soil moisture content at the 5-cm depth was also measured using a hand-held frequency-domain reflectometer（ML2x,Delta-T Devices Ltd,UK） at five locations close to the outer edge of each PVC collar.During the experimental period,the mean Rs in CK was 3.23 μmol m-2 s-1.DL significantly increased Rs in CK by 26%（P = 0.091） while NL significantly decreased Rs in CK by 22%（P=0.099）.The maximum difference between the Rs of DL（or NL） and the Rs of CK occurred from July to September when air temperatures were high and rainfall was sufficient.Soil temperatures showed no treatment differences（P=0.48） but the difference of soil moisture contents wi

关 键 词：刺槐人工林 土壤呼吸 凋落物 黄土高原 

分 类 号：S714[农业科学—林学]