摘要
在六盘山香水河小流域的华北落叶松人工林样地,测定了2011年生长季降水转化过程中的大气降水、穿透水、干流、枯落物渗透水和主根系层(30 cm土层)土壤渗透水的pH值与多种阳离子的浓度及通量变化。结果表明:林外降水的pH值平均为7.13,转化为穿透雨和干流后降为6.73和6.00,转化为枯落物渗透水和土壤渗透水后回升为6.87和7.28。在降水转为由穿透雨和干流组成的林下降水后,绝大多数阳离子的浓度都不同程度地增大,但Zn2+浓度下降;虽然林冠截持使林下降水的数量减小,但由于雨水对林冠的离子交换及淋洗,林下降水的多数阳离子通量都比林外降水明显增大,K+、Mg2+、H+、Mn2+、Cu2+、Fe3+由林外的17.23、12.51、0.06、0.09、0.13、0.19 mmol.m-2分别上升到林下的141.87、32.93、0.10、0.68、0.24、0.56 mmol.m-2,但Na+、Ca2+、Zn2+的通量分别由林外的33.73、112.91、2.05 mmol.m-2减小为林内的30.70、75.75、1.10 mmol.m-2。在枯落物层渗透水中,绝大多数阳离子的浓度都不同程度地下降,仅Mg2+浓度微弱上升;受枯落物截持部分降水及雨水中阳离子与枯落物交换的影响,枯落物渗透水中所有阳离子的通量都比林下降水明显减小,K+、Na+、Mg2+、Ca2+、H+、Mn2+、Cu2+、Zn2+、Fe3+分别降至83.06、12.30、23.96、65.73、0.04、0.12、0.09、0.13、0.32 mmol.m-2。在主根系层土壤渗透水中,一些阳离子(K+、Mn2+、Cu2+、Fe3+)的浓度下降,另一些阳离子(Na+、Mg2+、Ca2+、Zn2+)的浓度则上升,尤其Ca2+浓度显著上升;Na+、Mg2+、Ca2+、Mn2+、Zn2+的通量比枯落物渗透水增大,其值分别为37.49、62.83、202.41、0.22、1.05 mmol.m-2,但K+、Cu2+、Fe3+的通量比枯落物渗透水减小,其值分别为27.14、0.07、0.09 mmol.m-2。相对于林外降水的阳离子输入通量,林冠层对多数阳离子(除Na+、Ca2+、Zn2+)的通量为净淋出(增加)作用,枯落物层对多数阳离子(除K+、Mg2+、Mn2+、Fe3+)的通量为净固定(减少)作用,主根系层土壤对盐基离子(Na+、K+、Mg2+、Ca2+)和Mn2+的通量为净淋失(增大)作用,但对其他阳离子(H+、Cu2+、Zn2+、Fe3+)的通量为净固定(减少)作用。
At a selected stand of Larix principis-rupprechtii plantation growing in the small watershed of Xiangshuihe of Liupan Mountains, NW China, the variation of pH-value, cation concentration and cation flux were measured in the rain water from open field precipitation, throughfall, stem flow, leakage under humus layer ana unuer me miner-al soil layer （30 cm） in the growing season of 2011. The results showed that the mean pH-value of open field rain water was 7.13, while it was 6. 73 in throughfall, 6. 00 in stem flow, 6. 87 in the leakage under humus layer and 7.28 in the leakage under the soil depth of 30 cm. In the rain water under canopy, which is composed of throughfall and stem flow, the concentration of nearly all cations increased more or less, but the concentration of Zn^2＋ de-creased. Although the depth of rain water under canopy decreased as a result of canopy interception, the cation ex- change or wash out from canopy led to an obvious increase of flux of most cations. The cation flux （ mmol · m^-2 ） for K^＋ , Mg^2＋ , H^＋ , Mn^2＋ , Cu^2＋, and Fe^3＋ increased from 17.23, 12. 51, 0. 06, 0.09, 0. 13, and 0. 19 of open field precipitation to 141.87,32. 93, 0. 10, 0. 68, 0.24, and 0. 56 of rain water under canopy. However, the flu-xes of Na^＋ , Ca^2＋ , Zn^2＋ decreased by the canopy, from 33.73 to 30. 70, 112. 91 to 75.75, and 2.05 to 1.10 re-spectively. In the leakage under humus layer, the concentration of most cations decreased more or less, only the concentration of Mg^2＋ increased slightly. Affected by the humus layer interception and the cation exchange with hu-mus layer materials, the flux of all cations in the leakage under humus layer obviously reduced compared with the flux carried by the rain water under canopy, with a flux （mmol · m^-2 ） of 83.06 for K^＋ , 12. 30 for Na ^＋ , 23.96 for Mg^2＋ , 65.73 for Ca^2＋ , 0.04 for H^＋ , 0. 12 for Mn^2＋ , 0. 09 for Cu^2＋, 0. 13 for Zn^2＋, and 0. 32 for Fe^3＋ In the leakage under the soil layer of main root system, the concentration of some cations （K^＋ , Mn^2＋, Cu^2＋ , Fe^2＋ ）re-duced, while the other cations （ Na^＋ , Mg^2＋ , Ca^2＋ , Zn^2＋ ） increased, especially the remarkable increase of Ca^2＋ concentration. Affected by the volume decrease of soil leakage and the cation exchange with soil, the flux of Na^＋ , Mg^2＋, Ca^2＋, Mn^2＋, and Zn^2＋ in soil leakage increased （ mmol · m^-2） of 37.49, 62. 83, 202. 41, 0. 22, and 1 compared with that of humus layer leakage, with the flux 05 respectively; but the cations of K ^＋ , Cu^2＋, Fe^3＋de-creased, with the flux （ mmol · m^-2 ） of 27.14, 0. 07, and 0. 09 respectively. Compared with the cation input flux carried by the open field precipitation, the canopy played a role of net leakage （increase） for most cations （ except Na^＋, Ca^2＋, Zn^2＋） , while the humus layer played a role of net adsorption （decrease） for most cations （except K ^＋ , Mg^2＋ , Mn^2＋, Fe^3＋ ）, and the soil of main root layer played a role of net leakage （increase） for the base cat-ions （ Na ^＋ , K^＋ , Mg^2＋ , Ca^2＋ ） and Mn^2＋ , and a role of net adsorption （decrease） for other cations （ H ^＋ , Cu^2＋ , Zn^2＋ , Fe^3＋ ）.
出处
《林业科学研究》
CSCD
北大核心
2013年第2期133-139,共7页
Forest Research
基金
林业公益性行业科研专项(201104005-02
200904056)
中挪合作项目"Forest in south China:An important sink for reactive ni-trogen and a regional hotspot for N_2O"
"十二五"科技支撑课题(2011BAD38B0503
2012BAD22B0301-1)
国家自然科学基金项目(41230852
41071023)
国家林业局森林生态环境与保护重点实验室和宁夏六盘山森林生态站资助
关键词
华北落叶松林
水文过程
阳离子
通量
变化
Plantation of Larix principis-rupprechtii
hydrological processes
cation
flux
variation
