湖南省4种森林群落土壤氮的矿化作用  

Net nitrogen mineralization in soils under four forest communities in Hunan Province

作　　者：王光军[1] 田大伦[1] 朱凡[1] 闫文德[1] 李树战[1] 

机构地区：[1]中南林业科技大学生命科学与技术学院,长沙410004

出　　处：《生态学报》2009年第3期1607-1615,共9页Acta Ecologica Sinica

基　　金：湖南省杰出青年基金资助项目(07JJ1004);国家林业局"948"资助项目(2007-4-19);国家自然科学基金资助项目(30571487);湖南省科技厅重点资助项目(06FJ3083;05NK3026);中南林业科技大学青年科学研究基金资助项目(07024B)

摘　　要：2007年7月,用树脂芯原位测定土壤无机氮含量的方法,对湖南杉木、马尾松、樟树和枫香4种森林群落的土壤氮矿化进行了研究。研究结果表明,经过28d培养,4种森林群落土壤中NH4+-N含量分别下降了31.4%～50.5%,NO3--N含量增加了8.2～17.3倍,氮矿化主要表现为硝化作用;氮矿化速率由大到小依次为樟树(0.05mg·kg-.1d-1)>马尾松(0.04mg·kg-.1d-1)>枫香(-0.12mg·kg-.1d-1)>杉木(-0.15mg·kg-.1d-1)。在4个森林群落的土壤中,NH4+-N是无机氮的主要存在形式,表现为在杉木群落中占78.42%、在马尾松中占79.17%、在樟树中占71.14%和枫香中占79.22%,而且NH4+-N的变化可以解释氮矿化量变化的96.1%～98.8%。土壤氮矿化速率与0～15cm土壤的C/N、pH值呈显著性正相关,但与凋落物量和0～30cm土壤中细根生物量相关性不显著。Nitrogen mineralization was evaluated in four forest communities in Hunan, which were Camphor community, Masson Pine community, Sweetgnm community, and Chinese Fir community. The resin-core technique was employed to determining net mineralization rates under field conditions. The N mineralization was analyzed before and after 28d. The results indicated that the ammonia nitrogen and nitrate nitrogen were 8.63 - 20.5 mg·kg^-1 and 0.27 - 0.64 mg·kg^-1 before the experiment, respectively. After 28d incubation, ammonia nitrogen decreased 31.4%- 50.5% and nitrate nitrogen increased 8.2 - 17.3 times among four forest communities. Net N mineralization rates was significantly different among those communities, the highest rate was measured in camphor communities （0.05mg·kg^-1·d^-1） and the lowest rate in Chinese Fir communities（ -0.15 mg·kg^-1·d^-1）. The ammonia nitrogen accounted for 78.42% , 79.17% , 71.14% and 79.22% of the inorganic nitrogen in Chinese Fir, Masson Pine, Camphor and Sweetgum communities, respectively. Ammonia nitrogen contributed 96.1%- 98.8% N mineralization. The net nitrogen mineralization rate was significantly correlated with soil C/N ratio and pH value in 0 - 15cm soil layer and no significant correlations was found with litter and fine root in 0 -30cm soil layer of all forest communities.

关 键 词：森林群落 树脂芯法 净氮矿化速率 湖南 

分 类 号：S714[农业科学—林学]