模拟氮沉降对森林土壤有机物淋溶的影响  

Effects of Simulated Nitrogen Deposition on Organic Matter Leaching in Forest Soil

作　　者：段雷[1] 马萧萧[1] 余德祥 谭炳全 

机构地区：[1]清华大学环境学院,环境模拟与污染控制国家重点联合实验室,北京100084 [2]重庆市沙坪坝气象局,重庆400030

出　　处：《环境科学》2013年第6期2422-2427,共6页Environmental Science

基　　金：国家自然科学基金项目(20877047);环境保护公益性行业科研专项(200909003)

摘　　要：在重庆铁山坪马尾松林内施加与大气氮沉降量相当的硝酸铵(NH4NO3)和硝酸钠(NaNO3),研究氮沉降加倍对土壤溶液可溶性有机物浓度的影响,分析氮沉降对森林土壤碳库的潜在作用.2005年起为期5a的现场观测表明,施氮后凋落物层土壤溶液的可溶性有机碳(DOC)浓度和通量在起初2a内与对照样区相比有明显升高,但之后反而降低.施氮还会降低凋落物层土壤溶液的DOC与DON(可溶性有机氮)比值,以及矿质土壤上层的DOC浓度,但对矿质土壤下层的DOC淋溶通量几乎没有影响.总体来看,在试验期内氮沉降对土壤碳库无显著影响,但土壤有机物可能有从富碳有机物向富氮有机物转化的趋势,氮沉降的成分(NH4+和NO3-)对土壤有机物的影响则没有明显差异.The impact of nitrogen deposition on the dynamics of carbon pool in forest soil was studied through a field experiment at Tieshanping,Chongqing in Southwest China.The changes of dissolved organic matter（DOM） concentration in soil water in different soil layers were monitored for five years after addition of ammonium nitrate（NH4NO3） or sodium nitrate（NaNO3） at the same dose as the current nitrogen deposition to the forest floor.The results indicated that the concentration and flux of dissolved organic carbon（DOC） were increased in the first two years and then decreased by fertilizing.Fertilizing also reduced the DOC/DON（dissolved organic nitrogen） ratio of soil water in the litter layer and the DOC concentration of soil water in the upper mineral layer,but had no significant effect on DOC flux in the lower soil layer.Although there was generally no effect of increasing nitrogen deposition on the forest carbon pool during the experimental period,the shift from C-rich to N-rich DOM might occur.In addition,the species of nitrogen deposition,i.e.,NH4＋ and NO3-,did not show difference in their effect on soil DOM with the same equivalence.

关 键 词：可溶性有机物 可溶性有机碳(DOC) 土壤碳库 氮沉降 氮饱和 马尾松林 

分 类 号：X53[环境科学与工程—环境工程]