酸沉降下韶山森林氮的输入、输出通量变化特征

以韶山蔡家塘森林小流域2001年实地监测的大气降水、穿透水和地表水数据为基础,对酸沉降作用下韶山森林N的输入、输出的月均通量及变化特征进行了研究.结果表明:2001年N输入通量为53.81 kg/hm2,主要以NH₄+ 形式(占总输入的64%)输入该森林生态系统;2001年N输出通量为3.57 kg/hm2,主要以NO₃-形式(占总输出的64%)输出该森林生态系统.韶山森林2001年N净滞留量达到50.24 kg/hm2.月均输出通量极大值出现在降雨量较多的5-7月,其N输出通量占全年N总输出通量的59%.从N的总输入通量、总输出通量的变化来看,N输出并不随输入的增加而增加,N的输出主要受到降水量的影响. 

Input-Output Flux of Nitrogen under Acid Deposition in the Forest in Shaoshan City

The monthly input-output flux of nitrogen as well as its variation characteristics under acid deposition at Caijiatang small forested catchment in Shaoshan City,Hunan Province was examined,based on the monitoring data of bulk precipitation,throughfall and runoff during 2001.Results showed that the N-input flux in 2001 was 53.81 kg/hm~2,in which the flux of NH_4~ accounted for 64%.The N-output flux in 2001 was 3.57 kg/hm~2,in which the flux of NO_3~-accounted for 64%,which indicated a net retention of 50.24 kg/hm~2 in CJT catchment.The maximum monthly flux occurs in May,June and July,with the total N-output in these three months accounting for 59% of the total N-output in the whole year.In general,the output of N does not increase along with the increasing input of N,but is mostly influenced by the rainfall quantity.