北京西山不同人工林枯落物层的水化学性质

通过采集降雨经枯落物后的水样,初步研究了北京西山地区油松林和栓皮栎林林下枯落物层的水化学性质.结果表明:大气降水经过林冠进入枯落物层后,油松林和栓皮栎林林下不同元素的浓度发生明显变化.枯落物水中K 、Na 、Ca2 、Mg2 、NH4 -N和NO3--N的浓度随时间的变化趋势基本一致.穿透雨经过枯落物层后,水中K 、Na 、Ca2 和Mg2 的平均浓度增加,而NH4 -N、NO3--N的平均浓度减小.其中,栓皮栎林和油松林中Ca2 浓度分别增加了7.54和5.27mg.L-1.栓皮栎林下枯落物层中K 、Na 、Ca2 、Mg2 的平均浓度高于油松林,而NH4 -N、NO3--N的平均浓度则低于油松林;经降水淋溶作用后,栓皮栎林和油松林林下枯落物归还林地的养分分别为41.59和58.12kg.hm-2,其中归还林地较多的是Ca2 ,其次是K .

Hydro-chemical properties of litter layer in two kinds of plantations in Beijing Xishan Mountain

The study on the hydro-chemical properties of litter layer in Pinus tabulaeformis and Querous variabilis plantations in Beijing Xishan Mountain showed that after the precipitation passed through the plantations and penetrated into litter layer, the element concentrations in precipitation changed greatly. The concentrations of K+, Na+, Ca2+, Mg2+, NH4+ -N and NO3- -N in litter water had similar changing trends as those in throughfall. The average concentrations of K+, Na+, Ca2+ and Mg2+ in litter water were higher than those in throughfall, but NH4+ -N and NO3- -N were in adverse. Ca2+ increased most, with the increment of 7.54 mg x L(-1) in Q. variabilis plantation and 5.27 mg x L(-1) in P. tabulaeformis plantation. The concentrations of K+, Na+, Ca+, Mg2+ in litter water were higher in Q. variabilis than in P. tabulaeformis plantation, but NH4+ -N and NO3- -N concentrations were lower in Q. variabilis than in P. tabulaeformis. After leaching by precipitation, the nutrients return into woodland was 41.59 kg x hm(-2) in Q. variabilis and 58.12 kg x hm(-2) in P. tabulaeformis, among which, Ca2+ returned more, followed by K+.