摘要
通过研究土壤活性碳、氮的季节变化及其影响因素,为揭示人工林生态系统土壤碳、氮周转机理提供理论依据。以华北石质山区侧柏、刺槐和栓皮栎3种典型人工林为对象,设置有枯落物归还和无枯落物处理,在3、6、9和12月份采集表层0～10 cm土样,动态监测不同人工林下土壤溶解性有机碳、溶解性有机氮、无机氮、硝态氮和铵态氮的季节性变化规律。研究结果表明:1) 3种人工林下土壤溶解性有机碳、溶解性有机氮、无机氮、硝态氮和铵态氮质量分数呈显著的季节变化(P <0. 05),且有相似的趋势,均在6月达到峰值。2)土壤无机氮主要以NO_3^--N形式存在,侧柏林、刺槐林和栓皮栎林下土壤NO_3^--N质量分数分别为70. 2%、72. 8%和53. 4%。3)人工林类型显著影响林下土壤溶解性有机碳和NO_3^--N质量分数(P <0. 05),有枯落物处理时年均土壤溶解性有机碳和溶解性有机氮质量分数均呈侧柏>栓皮栎>刺槐的趋势,4)而NO_3^--N和NH_4^+-N和无机氮质量分数呈侧柏>刺槐>栓皮栎的趋势。枯落物处理显著影响土壤溶解性有机碳和溶解性有机氮质量分数(P <0. 05),对土壤NO_3^--N和NH_4^+-N质量分数无显著影响,土壤溶解性有机碳和溶解性有机氮质量分数大多呈有枯落物处理高于无枯落物处理的规律。5)逐步回归分析结果表明,土壤溶解性有机碳质量分数主要受土壤总氮质量分数的影响,其可解释74. 6%的变化;土壤溶解性有机氮主要受土壤总氮、NO_3^--N、气温和NH_4^+-N质量分数的影响,它们可共同解释86. 6%的变化。不同人工林类型显著影响了土壤活性碳、氮的季节变化;枯落物的归还提高并促进了人工林下土壤碳、氮含量和周转速率。
[Background]Soil active carbon and nitrogen are the most important and active components during soil carbon and nitrogen cycling,and their seasonal changes are of great significance to carbon and nitrogen cycling and redistribution within and between different ecosystems,as well as soil formation.To reveal soil carbon and nitrogen turnover mechanism in artificial forest ecosystem,seasonal dynamics of soil active carbon and nitrogen contents and other factors were determined.[Methods]Three typical artificial forests(Platycladus orientalis,Robinia pseudoacacia and Quercus variabilis)in the rocky mountainous area of northern China were selected as the research objects.Two treatments were set up,i.e.,Y(with litter return)and W(without litter return).The characteristics and variation trends of dissolved organic carbon(DOC)and dissolved organic nitrogen(DON)and inorganic nitrogen(SIN,including NO3--N and NH4+-N)contents at the depth of 0-10 cm soils were investigated during March,June,September and December.[Results]The DOC,DON,NO3--N and NH4+-N contents in the 3 artificial forests soils all showed general significant seasonal dynamics(P<0.05),with peak values in June.NO3--N was the main form of inorganic nitrogen in soils,and its ratio to SIN in P.orientalis,R.pseudoacacia and Q.variabilis artificial forests were 70.2%,72.8%and 53.4%,respectively.Artificial forest types had a significant impact on soil DOC and NO3--N contents(P<0.05).The annual average of soil DOC and DON contents with litter return presented as P.orientalis>Q.variabilis>R.pseudoacacia,while soil NO3--N,NH4+-N and SIN contents tended to be as P.orientalis>R.pseudoacacia>Q.variabilis.Litter treatments had a significant impact on soil DOC and DON contents(P<0.05),while no significant impact on soil NO3--N and NH4+-N contents.Further,most of forests soil without litter return showed higher DOC and DON concentrations than those of with litter return.A stepwise regression analysis showed that the main influencing factor of soil DOC in all treatments was soil total nitrogen(TN),which explained 76.4%of its variation.The main influencing factors for soil DON were soil TN,NO3--N,air temperature and NH4+-N,which together explained 86.6%of its variation.[Conclusions]Different artificial forest types significantly affected the seasonal variation of soil active carbon and nitrogen.Litter returns increased soil carbon and nitrogen content and turnover rate.Further,temperature was the main driving factor for soil active carbon and nitrogen turnover in the rocky mountainous areas of North China.Besides,soil DOC and DON turnover were mainly affected by soil TN content in the present artificial forest ecosystem.
作者
孔玉华
韩梦娟
张志华
徐星凯
赖勇
杨喜田
KONG Yuhua;HAN Mengjuan;ZHANG Zhihua;XU Xingkai;LAI Yong(College of Forestry,Henan Agricultural University,450002,Zhengzhou,China;State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,810016,Xining,China;State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,100029,Beijing,China;College of Earth Science,University of Chinese Academy of Sciences,100049,Beijing,China)
出处
《中国水土保持科学》
CSCD
北大核心
2019年第2期44-52,共9页
Science of Soil and Water Conservation
基金
国家自然科学基金"太行山区侧柏人工林土壤有机碳固存与周转机理研究"(41501331)
国家自然科学基金"林木幼苗对切根的生理生态响应及根-冠互作机制"(31570613)
关键词
人工林类型
土壤溶解性有机碳
土壤溶解性有机氮
土壤无机氮
华北石质山区
artificial forest types
soil dissolved organic carbon
soil dissolved organic nitrogen
soil inorganic nitrogen
rocky mountainous area of northern China
