摘要
为探讨不同封育年限荒漠草原土壤有机碳矿化对枯落物添加的响应特征,选取未封育(GG)、封育5年(FG_5)、9年(FG_9)和12年(FG_(12))的荒漠草原为研究对象,通过室内培养研究了添加牛枝子枯落物(N+S)、蒙古冰草枯落物(M+S)、短花针茅枯落物(D+S)和混合枯落物(H+S)对不同封育年限荒漠草原土壤有机碳矿化的影响。结果表明,1)枯落物添加显著提高了各封育年限草地土壤有机碳矿化速率和累积矿化量,未封育和封育9年的草地以添加混合枯落物的累积矿化量最高,分别为13.81和15.80 mg·kg^(-1);封育5年和12年的草地则以添加蒙古冰草枯落物的累积矿化量最高,分别达到15.04和13.47 mg·kg^(-1)。添加枯落物后各封育年限草地土壤有机碳的矿化大致可划分为3个阶段:0～6 d为迅速释放阶段(活性碳库),7～62 d为缓慢释放阶段(慢性碳库),63～76 d为稳定释放阶段(惰性碳库)。2)一级动力学方程能够较好地拟合土壤有机碳矿化动态(R^2=0.815～0.932),封育5年的草地土壤矿化潜势最高,为(8.834±0.382) mg·kg^(-1)。3)枯落物添加对各封育年限草地土壤有机碳矿化产生了正激发效应,以封育9年草地的激发效应最强。冗余分析(redundancy analysis,RDA)排序结果表明枯落物有机碳和全氮对土壤有机碳矿化有显著影响(F=15.314,P=0.002;F=8.669,P=0.008),累积解释量为70.87%。
This experiment aimed to explore the soil organic carbon mineralization response to litter addition in desert steppe grassland sites with differences in number of years grazing exclusion by fencing. The sites studied were grazed and never fenced(GG), fenced 5 years(FG5), fenced 9 years(FG9) and fenced 12 years(FG12). The effects on soil organic carbon mineralization, of adding litter samples including material from Lespedeza potaninii(N+S), Agropyron mongolicum(M+S), Stipa breviflora(D+S) and mixed plants(H+S) to soil samples from the desert steppe grassland sites with different fencing durations were determined after a laboratory incubation period of 76 days. It was found that: 1) Litter addition significantly increased the soil organic carbon mineralization rate and the cumulative mineralization of the soil samples, irrespective of the fencing duration. For the GG and FG9 samples, the cumulative mineralization was highest with H+S litter addition(13.81 and 15.80 mg·kg-1, respectively). For the FG5 and FG12 sites, the greatest mineralization occurred with the addition M+S litter(15.04 and 13.47 mg·kg-1, respectively). The mineralization process could be roughly divided into three stages: 0-6 d for rapid release(activate carbon pool), 7-62 d for slow release(long-term carbon pool) and 63-76 d for stable C release(inert carbon pool). 2) The first-order kinetic equation was well matched to the mineralization dynamics of soil organic carbon(R2=0.815-0.932), and the potential mineralization of soil was highest in FG5 grassland(8.834±0.382 mg·kg-1). 3) Litter addition had a positive priming effect on soil organic carbon mineralization in grasslands of different fencing durations, with the priming effect being strongest in soil from the FG9 site. Representational difference analysis(RDA) sequencing showed that the organic carbon and total nitrogen of litter had significant effects on soil organic carbon mineralization(F=15.314, P=0.002;F=8.669, P=0.008, respectively, with cumulative R2 of 70.87%).
作者
刘金龙
王国会
许冬梅
许爱云
于双
LIU Jin-long;WANG Guo-hui;XU Dong-mei;XU Ai-yun;YU Shuang(College of Agriculture, Ningxia University, Yinchuan 750021, China;State Key Laboratory Breeding Base of Land Degradation and Ecological Restoration of Northwest China, Ningxia University, Yinchuan 750021, China)
出处
《草业学报》
CSCD
北大核心
2019年第4期47-57,共11页
Acta Prataculturae Sinica
基金
国家自然科学基金(31460624)
宁夏高等学校一流学科建设(草学学科)项目(NXYLXK2017A01)资助
关键词
荒漠草原
封育
枯落物
有机碳矿化
激发效应
desert steppe
fenced
litter
organic carbon mineralization
priming effect
