林地大气氮沉降通量观测对比研究

Comparative study on the observation of atmospheric nitrogen deposition in a forestland

以中国科学院红壤生态实验站森林微气象分站阔叶林为研究对象,采用穿透雨量法和微气象学推论法对该阔叶林地大气氮沉降通量进行了对比研究.结果表明,穿透雨量法观测2006年10月-2007年9月林地NH4+-N干沉降通量为37.66kg N/(hm2·a),NO3--N干沉降通量为18.53kgN/(hm2·a),其中NH4+-N是氮化物干沉降的主要贡献者,占总干沉降的67.0%.该研究方法所得结果与微气象学方法观测结果具有较好的一致性,表明穿透雨量法估算林地氮干沉降通量具有一定的可靠性.微气象学法与穿透雨量法观测结果共同说明研究地大气氮沉降量较高,过量的氮输入对研究地生态系统的影响值得关注.

Comparative study on atmospheric nitrogen deposition was conducted using throughfall method and micrometeorological inferential method with study object of broadleaf forest （Quercus chenii） at Forest Micrometeorological Experiment Sub-Station, Experiment Station of Red Soil Ecology, Chinese Academy of Sciences. The results observed by throughfall method from Oct. 2006 to Sep. 2007 showed that NH4^＋-N and NO3 -N dry deposition were 37.7 and 18.5kgN/（hm2.a）, respectively, in which NH4^＋-N were the predominant contributors, accounting for 67.0% of total dry deposition. These results were in agreement with those obtained by micrometeorological inferential method, indicating that throughfall method was reliable in the estimation of nitrogen dry deposition under forestland. Results obtained from these two methods confirmed that excessive N deposition fluxes occurred in the study area, and that their effects on various ecosystems should be paid more attention.