CATION DISTRIBUTION, CYCLING, AND REMOVAL FROM MINERAL SOIL IN DOUGLAS-FIR AND RED ALDER FORESTS
CATION DISTRIBUTION, CYCLING, AND REMOVAL FROM MINERAL SOIL IN DOUGLAS-FIR AND RED ALDER FORESTS
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DOI：
10.1007/bf00002828
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发表时间：
1992-01-01
期刊：
影响因子：
4
通讯作者：
WOLFE, GV
中科院分区：
文献类型：
--
作者：
HOMANN, PS;VANMIEGROET, H;WOLFE, GV
林下物种影响着森林生态系统中养分的分布和动态。生态系统水平的估计钙，镁，钾库和循环在50岁的花旗松和红桤木林被用来确定净阳离子去除的矿质土壤，即阳离子出口从土壤中超过添加物的上层组成的影响。从花旗松土壤净阳离子去除8公斤钙公顷-1年-1，1公斤镁公顷-1年-1，和0.3公斤钾公顷-1年-1。每年阳离子出口从土壤中的吸收和积累活的木质组织和O层是类似的幅度在土壤溶液中的淋溶。大气沉降通过增加相当于阳离子输出的28-88%的阳离子部分抵消输出。从红桤木土壤净阳离子去除量为58公斤钙公顷-1年-1，9公斤镁公顷-1年-1，和11公斤钾公顷-1年-1。年阳离子积累活木质组织和O层是3倍以上的花旗松，而土壤溶液中的阳离子淋溶是5至8倍。红桤木土中交换性阳离子没有过度耗竭，表明矿物风化作用，而不是交换性阳离子。是大多数被去除的阳离子的来源。硝化过程中产生的硝酸在红桤木土导致高速率的风化和NO3驱动的阳离子淋溶。
Overstory species influence the distribution and dynamics of nutrients in forest ecosystems. Ecosystem-level estimates of Ca, Mg, and K pools and cycles in 50-year old Douglas-fir and red alder stands were used to determine the effect of overstory composition on net cation removal from the mineral soil, i.e. cation export from the soil in excess of additions. Net cation removal from Douglas-fir soil was 8 kg Ca ha-1 yr-1, 1 kg Mg ha-1 yr-1, and 0.3 kg K ha-1 yr-1. Annual cation export from soil by uptake and accumulation in live woody tissue and O horizon was of similar magnitude to leaching in soil solution. Atmospheric deposition partially off-set export by adding cations equivalent to 28-88% of cation export. Net cation removal from red alder soil was 58 kg Ca ha-1 yr-1, 9 kg Mg ha-1 yr-1, and 11 kg K ha-1 yr-1. Annual cation accumulation in live woody tissue and O horizon was three times greater than in Douglas-fir, while cation leaching in soil solution was five to eight times greater. The lack of excessive depletion of exchangeable cations in the red alder soil suggests that mineral weathering, rather than exchangeable cations. was the source of most of the removed cations. Nitric acid generated during nitrification in red alder soil led to high rates of weathering and NO3-driven cation leaching.