摘要
为了解采伐林窗对马尾松人工林土壤有效氮的影响,在长江上游低山丘陵地区,选取人为采伐形成的马尾松(Pinus massoniana)人工林7种不同大小林窗(G1-G7,面积分别为100 m2、225 m2、400 m2、625 m2、900 m2、1 225 m2、1 600 m2)以及林下对照为研究对象,研究林窗中央和边缘铵态氮(NH4+-N)和硝态氮(NO3--N)的生长季变化.结果显示:林窗形成初期,其大小仅对土壤NH4+-N有显著影响,季节变化仅对NO3--N有显著影响,但两者对土壤NH4+-N、NO3--N均有显著的交互作用,林窗中央和边缘间土壤NH4+-N、NO3--N差异均不显著.具体为:(1)林窗土壤NH4+-N含量为4.30-11.99 mg kg-1,NO3--N含量为2.57-10.81 mg kg-1;不同大小林窗间NH4+-N、NO3--N仅在生长季中期总体随林窗增大先升后降;总的来看,面积为100-400 m2的林窗土壤NH4+-N、NO3--N较高.(2)在季节动态上,NH4+-N在生长季中期较低;NO3--N为中高末低.同时,生长季初期和末期NH4+-N高于NO3--N,而中期却相反.(3)较之林下,生长初期及末期部分林窗土壤NH4+-N、NO3--N降低.(4)相关分析表明,NH4+-N与微生物生物量氮(MBN)极显著正相关,NO3--N与土壤温度、MBN和有机质均极显著正相关,但土壤含水量对NH4+-N、NO3--N均无显著影响.因此,林窗对土壤温度及微生物活性的改变可能是影响土壤有效氮含量的主要因素.
To understand the short-term effects of forest gap by human harvesting on soil available nutrient in Pinus massoniana plantations,the variations of soil ammonium nitrogen（NH4^＋-N） and nitrate nitrogen（NO3^--N） concentrations in the gap center and gap edge during growing season were observed in seven gaps of different size（Gl：100 m^2;G2：225 m^2;G3：400 m^2;G4：625 m^2;G5：900 m^2;G6：1225 m^2;G7：1600 m^2） and pure understory of a 39-year-old masson pine plantation in a hilly area of the upper reaches of Yangtze River.The results showed that in the early stage of gap formation,the gap size had significant effect on NH4^＋-N,the season changes on NO3^--N,and the interaction effect of gap size and seasonal variation on NH4^＋-N and NO3^--N.The difference of NH4^＋-N and NO3^--N between the gap center and gap edge was not significant.（1）The NH4^＋-N content was 4.30- 11.99 mg kg^-1,and NO3^--N content was 2.57- 10.81 mg kg^-1.There was no obvious difference in NH4^＋-N and NO3^--N among gaps of different size in early or late growing seasons,when both increased first and decreased afterwards in the middle of growing season.The gaps of 100-400 m^2 area had a higher content of available nitrogen.（2）The seasonal dynamic differed between NH4^＋-N and NO3^--N,with the former lower in middle growing season whereas the latter higher in the middle growing season but lower in the end of growing season.The soil NH4^＋-N was higher than NO3^--N in the early and late periods,but lower in the middle period.（3） The soil NH4^＋-N and NO3^--N in parts of gaps were lower than understory in the early and late growing season.（4） Correlation analyses showed that NH4^＋-N had significant positive correlation with microbial biomass nitrogen（MBN）,and NO3^--N with soil temperature,MBN and organic matter.But the impact of soil water content on available nitrogen was not significant.These results suggested that soil temperature and microbial activity variation caused by gap harvesting are th
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2015年第1期147-154,共8页
Chinese Journal of Applied and Environmental Biology
基金
国家科技支撑计划项目(2011BAC09B05)
国家自然科学基金项目(31370628)
四川省科技支撑计划项目(12ZC0017)
四川省科技厅应用基础项目(2012JY0047)
四川省教育厅科技创新团队计划项目(11TD006)资助~~
关键词
林窗大小
低效人工林
生长季
铵态氮
硝态氮
土壤微生物
单因素试验
gap size
low-efficient plantation
growing season
ammonium nitrogen
nitrate nitrogen
soil microbe identification
single factor tests
