亚热带常绿阔叶林和杉木人工林茎流与穿透雨的养分特征

亚热带常绿阔叶林和杉木人工林树干茎流和穿透雨养分含量均表现季节动态变化。养分含量中,K^ 、Ca^2 、NO3%-浓度高,Na^ 、Mg^2 居中,HPO4^2-含量低,相对于林外雨,养分均出现富集化,但树干茎流养分富集化高于穿透雨。树干茎流出现强烈的酸化,而穿透雨酸化现象不明显。树种之间的茎流养分特征表现不一样,樟树和枫香总的养分浓度较高,其次为刨花楠,最后为青冈和红栲。     

川西亚高山白桦林穿透雨和茎流特征观测研究

观测了川西亚高山白桦次生林一个生长季节内的穿透雨和茎流的特征。结果表明 ,幂函数方程能较好地拟合林冠截留量、茎流量与总降雨量之间的关系 ,而线性方程能较好地拟合穿透雨量和总降雨量之间的关系 ;平均林冠截留量占总降雨量的 1 8 9% ,穿透雨量占总降雨量的 80 9% ,茎流量占总降雨量的 0 3%。     

鼎湖山季风常绿阔叶林大气降雨、穿透雨和树干流的养分特征研究

对鼎湖山季风常绿阔叶林大气降雨、穿透雨和树干茎流中的5种养分元素K、Ca、Mg、N、P进行了测定,结合水量分配规律,研究了森林降雨过程中养分在水相中的含量变化特征和输入规律。结果表明：(1)所有离子浓度均为大气降水<穿透雨<树干流,且增幅较大,而平均浓度以K+和总氮(TN)含量最高;总磷(TP)、磷酸盐(HPO42-)、总有机磷(TOP)含量均最低。(2) 大气降雨中的离子平均浓度中以总有机氮(TON)的变异系数最大,为1.282;最小的是NO3-(0.502);穿透雨中变异系数最大的是TOP(2.357);最小的是TN(0.621)。树干流中各养分元素浓度与树种的相关性不显著(P>0.05)。(3) 季风常绿阔叶林树干流和穿透雨各养分对森林土壤的年输入量为TN>K+>Ca2+>Mg2+>TP,树干流和穿透雨对森林土壤层Ca2+的输入大于凋落物分解输入。因此,大气降雨是养分从林冠层转移到土壤层的重要因素。     

华北暖温带山地落叶阔叶混交林的茎流研究

测定华北暖温带山地落叶阔叶混交林的树干茎流量及其元素含量,并比较了不同树种是的差异。通过８２次孤立降雨的测量,得到了辽东栋、棘皮桦、五角枫、大叶白腊和蒙椴５种主要树种及整个林分茎流量Ｓ与降雨Ｐ的关系,经多种方程拟合,仍以直线方程为最佳。降雨水质分析的结果给出了Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ、Ａｌ、Ｓ元素各次测量的美元浓度及其变异系数,以及年输入量的估测值,茎流元素含量的分析结果表明,５种乔木中,以棘皮桦的     

三种阔叶次生林的茎流研究

本文测定了白桦林、水曲柳林、蒙古栎林的树干茎流量及其养分元素含量,结果表明:三个林分的茎流差异十分明显(白桦:水曲柳:蒙古栎≈1:2:3),这种差异与树叶形态、枝条分枝角度及林分的叶面积指数有关。茎流中绝大多数元素的含量显著地高于降雨中的含量。蒙古栎林借助于它的形态结构使其根系区域获得的水分、养分最多,从而有助于它适应干旱、瘠薄的立地环境。     

贡嘎山暗针叶林生态系统基于KDW运动-弥散波模型的优先流研究

利用自制的土柱装置,开展室内土柱实验,并与野外实地示踪影像分析相结合,针对研究区域土壤包气带根系层中水分快速运动的优先流展开研究,其目的在于系统分析优先流对径流过程的影响,为长江上游暗针叶林生态系统土壤水分运动规律研究及有效流域管理提供理论支持。研究采用雷诺数计算及野外示踪映像分析方法,判定证明在所研究地区,有优先流现象发生,优先流是处于层流及紊流之间的过渡流。同时针对成熟林坡积物土壤的水分运移状况分析表明研究区域的壤中流过程主要表现为优先流,而土壤中的基质部分,则表现为不动区域。研究在以往优先流模型构建的基础上,综合考虑了研究区域的实地情况,应用融入弥散波的运动波模型(KDW优先流模型),利用交叉模拟方法和统计分析方法将此模型与实地实验检验分析,认定KDW优先流模型实用性强、可靠程度较高,可较好地模拟贡嘎山暗针叶林生态系统实地。     

鼎湖山区域大气降水特征和物质元素输入对森林生态系统存在和发育的影响

通过对鼎湖山区域大气降水特征及降水的物质元素输入的观测分析,得到如下一些主要结果①本区域年内降水分配不均,而热量输入却相对均匀,使整个区域湿季水土流失和干季水分亏匮的可能性加大.区域内的对比研究发现,无论从降水的季节差异,全年的暴雨降水量,多年的降水变率等方面,鼎湖山都比鹤山偏小,这对鼎湖山森林景观的形成起到了重要的作用.②该区的年降水量主要是湿季降水量存在着显著的7a周期性振荡现象.③大气降水中氮的含量偏高,浓度为1.92mg·L-1,总含N量为38.4 kg·hm-2·a-1;而钠、镁的含量偏低,浓度分别为0.105 mg·L-1和0.061mg·L,总含量分别为2.10 kg·hm-2·a-1和1.22 kg·hm-2·a-1.年内降水的集中使得生态系统的养分输入主要在湿季,与高温多雨处于同一时期,有利于森林植被的形成和森林生态系统生产力的提高.从水热角度出发,鼎湖山地带性森林的存在不仅是季风气候的结果,和同区域的其它地方相比,也是这里的降水季节性差异,降水变率和暴雨降水量较小的结果;根据区域性水热特性的分析,认为,鼎湖山地带性森林是一个非常脆弱的生态系统.     

鼎湖山季风常绿阔叶林大气降雨、穿透雨和树干流的养分特征

对鼎湖山季风常绿阔叶林大气降雨、穿透雨和树干茎流中的5种养分元素K、Ca、Mg、N、P进行了测定,结合水量分配规律,研究了森林降雨过程中养分在水相中的含量变化特征和输入规律。结果表明:(1)所有离子浓度均为大气降水穿透雨树干流,且增幅较大,而平均浓度以K+和总氮(TN)含量最高;总磷(TP)、磷酸盐(HPO42-)、总有机磷(TOP)含量均最低。(2)大气降雨中的离子平均浓度中以总有机氮(TON)的变异系数最大,为1.282;最小的是NO3-(0.502);穿透雨中变异系数最大的是TOP(2.357);最小的是TN(0.621)。树干流中各养分元素浓度与树种的相关性不显著(P0.05)。(3)季风常绿阔叶林树干流和穿透雨各养分对森林土壤的年输入量为TNK+Ca2+Mg2+TP,树干流和穿透雨对森林土壤层Ca2+的输入大于凋落物分解输入。因此,大气降雨是养分从林冠层转移到土壤层的重要因素。     

两种落叶分解过程中养分和碳素的行为

利用分解袋法对日本亚高山针叶林的针叶(Abies veitchii Lindl,and A.mariesi Mast.)和阔叶(Betula ermanii Cham.and B.corylifolia Regal.et Maxim．)凋落物进行了分解实验研究。结果表明尽管分解初期的两种凋落物的养分以及分解后期凋落物剩余重量差异很大,但两种凋落物养分浓度在分解后期(30个月以后)趋于一致。这种趋同现象在不同养分中有不同的趋同机制。氮元素浓度升高到分解后期浓度差变小,这种现象是由于分解菌的固持作用及受木质素的束缚所致;钾和镁在分解初期浓度急剧下降,进而浓度差变小,是由于淋溶作用所致。在分解过程中这些元素非常容易被淋溶掉,直到和土壤中的浓度达到一致为止。钙是结构元素,它的行踪和有机物组分有密切关系。由于分解后期有机组分木质化和腐殖质化进而浓度趋同,所以钙的浓度也相应趋同。     

两种落叶分解过程中养分和碳素的行为

利用分解袋法对日本亚高山针叶林的针叶(Abies veitchii Lindl.and A.mariesiMast.)和阔叶(Betulaermanii Cham.and B.corylifolia Regal.et Maxim.)凋落物进行了分解实验研究.结果表明尽管分解初期的两种凋落物的养分以及分解后期凋落物剩余重量差异很大,但两种凋落物养分浓度在分解后期(30个月以后)趋于一致.这种趋同现象在不同养分中有不同的趋同机制.氮元素浓度升高到分解后期浓度差变小,这种现象是由于分解菌的固持作用及受木质素的束缚所致;钾和镁在分解初期浓度急剧下降,进而浓度差变小,是由于淋溶作用所致.在分解过程中这些元素非常容易被淋溶掉,直到和土壤中的浓度达到一致为止.钙是结构元素,它的行踪和有机物组分有密切关系.由于分解后期有机组分木质化和腐殖质化进而浓度趋同,所以钙的浓度也相应趋同.     

长白山红松云冷杉林林内降水的养分输入

1 引言 在林地里,树木的叶子、枝条、树皮、果实,有时甚至整株树木都周期性地归还土壤,这种凋落物养分归还是森林生态系统的一个重要特点。但林木吸收的大部分养分,除由凋落物归还土壤外,还能由树冠淋洗归还土壤,在我国东北地区森林生态系统研究工作中,红     

Solute fluxes in throughfall and stemflow in four forest ecosystems in northwest Amazonia

The contribution of throughfall and stemflow as pathways for solute inputs into the forest floor in four mature forests in northwest Amazonia was investigated. Total solute inputs, resulting from the changes of atmospheric deposition after rainfall passes through the forest canopy, are presented in the form of throughfall and stemflow nutrient inputs and their possible sources are discussed. Throughfall is by far the most important solute input into the forest floor of the forests studied. On average, it represents about 98% of the total solute inputs. Although trends in solute enrichment varied among the forests, there is a general tendency in all ecosystems towards a distinct enrichment of SO₄, K, Cl, NO₃ and NH₄ in throughfall and stemflow and a small increase of protons, Mn, orthoP and Fe. When comparing the net enrichment between the forests, the relative increase of solutes in throughfall and stemflow was higher in the flood plain and low terrace than in the high terrace and sedimentary plain forests. While highest values for total cation inputs were observed in the flood plain, the low terrace showed the highest value for total inorganic anions. The length of the antecedent dry period was the main factor affecting throughfall and stemflow composition, concentrations increasing with increasing length. A second, less important factor was the amount of throughfall and stemflow, which showed a poor and negative correlation with solute concentrations. The increased activity of frugivores in the canopy during fruiting periods seemed to lead to temporary increased solute concentrations in throughfall and stemflow as a result of the wash off of deposited faecal materials and detritus in the canopy. Leaching from leaves and wash off of exudes, of solutes deposited on the foliage after evaporation of intercepted rainfall and of dry deposited materials were all found to contribute to the concentration of solutes in the throughfall and stemflow. Gross rainfall enrichment after passing the forest canopy, mainly by nutrient leaching, is considerably lower than the amounts of nutrients released in litterfall implying a tight nutrient cycling and nutrient conserving mechanisms by forests studied.     

林冠分配降雨过程的模拟实验分析

实验发现,降雨通过林冠的穿透过程线、树干径流过程线与电感电容电阻串联电路暂态过程线极为相似。由此启发,用此电路暂态方程拟合穿透降雨与树干径流过程并求出了解析解。进而,根据余项法求出截留强度表达式。此举拓宽了森林水文学理论研究思路。     

Throughfall,stemflow and interception of rainwater in an evergreen broadleaved forest

In order to analyze the dyanmics of heavy metals in a forest ecosystem, throughfall and stemflow were collected for individual rain showers in an evergreen broad-leaved forest dominated byCastanopsis cuspidata. The relation between throughfall (or stemflow) (Px) and gross rainfall (P) was approximated by a linear regression equationPx=a(P-b). The values of coefficient “a” were 0.32–2.02 for throughfall at each sampling point and the mean values for 1976 and 1977–1978 were 0.682 and 0.767, respectively. The stemflow volume differed widely among individual trees, depending mainly on the tree form of each species. In particular, the tree form ofPasania edulis was found to be especially suited to collecting stemflow. OneP. edulis tree collected 64% of the rainwater that fell onto its crown as stemflow. The ratio of stemflow to gross rainfall decreased in summer resulting from an increase in leaf biomass and an increase in air temperature. In fact, the values of coefficient “a” for mean stemflow per unit area were 0.180 for summer and 0.229 for other seasons in 1976, and 0.145 for summer and 0.155 for other seasons in 1977–1978 for different sampled trees.     

鼎湖山森林凋落物量及营养元素含量研究

 本文研究了鼎湖山南亚热带常绿阔叶林和针叶林的凋落物量及凋落物中主要营养元素(N、P、K、Ca、Mg)的含量。8年的测定结果表明,两个森林类型的年均凋落物量(t·ha-1)及凋落物中主要营养元素的含量(t·ha-1·yr-1)分别为：常绿阔叶林9.056,0.220;针叶林2.695,0.032。凋落物中叶、枝和花果的百分组成及凋落特征各异。鼎湖山南亚热带常绿阔叶林的年均凋落物量低于热带雨林而高于暖温带落叶阔叶林,说明不同气候带的森林类型,其凋落物量是有差异的。与针叶林相比较,常绿阔叶林的凋落物量较大,凋落物中主要营养元素的含量较高,凋落物的分解速率也较快,因此从提高森林的质量和增强森林的生态效益来考虑,在造林绿化上应提倡多营造常绿阔叶林或针阔叶混交林。     

Seasonal and within-event dynamics of rainfall and throughfall chemistry in an open tropical rainforest in Rondônia,Brazil

Prolonged dry periods, and increasingly the generation of smoke and dust in partially-deforested regions, can influence the chemistry of rainfall and throughfall in moist tropical forests. We investigated rainfall and throughfall chemistry in a palm-rich open tropical rainforest in the southwestern Brazilian Amazon state of Rondônia, where precipitation averages 2300 mm year^?1 with a marked seasonal pattern, and where the fragmentation of remaining forest is severe. Covering the transition from dry to wet season (TDWS) and the wet season (WS) of 2004–2005, we sampled 42 rainfall events on event basis as well as 35 events on a within-event basis, and measured concentrations of DOC, Na⁺, K⁺, Ca²⁺, Mg²⁺, NH ₄ ⁺ , Cl^?, SO ₄ ^2? , NO ₃ ^? and pH in rainfall and throughfall. We found strong evidence of both seasonal and within-event solute rainfall concentration dynamics. Seasonal volume-weighted mean (VWM_S) concentrations in rainfall of DOC, K⁺, Ca²⁺, Mg²⁺, NH ₄ ⁺ , SO ₄ ^2? and NO ₃ ^? were significantly higher in the TDWS than the WS, while VWM_S concentrations in throughfall were significantly higher for all solutes except DOC. Patterns were generally similar within rain events, with solute concentrations declining sharply during the first few millimeters of rainfall. Rainfall and throughfall chemistry dynamics appeared to be strongly influenced by forest and pasture burning and a regional atmosphere rich in aerosols at the end of the dry season. These seasonal and within-event patterns of rainfall and throughfall chemistry were stronger than those recorded in central Amazônia, where the dry season is less pronounced and where regional deforestation is less severe. Fragmentation and fire in Rondônia now appear to be altering the patterns in which solutes are delivered to remaining moist tropical forests.     

模拟氮沉降下南方针叶林红壤的养分淋溶和酸化

以中国科学院红壤生态实验站林草生态试验区针叶林红壤为研究对象,在恒温(20 ℃)条件下,通过大土柱（直径10 cm、高60 cm）,8个月间隙性淋溶试验模拟研究了不同氮输入量（0、7.8、26和52 mg N/月/柱）对针叶林红壤NO₃^-、NH₄⁺、H⁺和土壤盐基离子(Ca²⁺、Mg²⁺、K⁺、Na⁺⁾淋溶以及土壤酸化的影响.结果表明,土壤交换态盐基总量、Ca²⁺和Mg²⁺淋溶量随氮输入量的增加而增加,土壤交换态Na⁺和K⁺则无明显影响.4种N输入处理的土壤交换态盐基总量净淋溶（淋溶出的盐基与淋洗液累计输入的盐基之差）分别占土壤交换性盐基总量的13.9%、18.6%、31.8% 和57.9％,土壤交换态Ca²⁺净淋溶分别占土壤交换性Ca²⁺总量的19.6%、25.8%、45.3%和84.8%,土壤交换态Mg²⁺净淋溶分别占土壤交换性Mg²⁺总量的4.4%、6.1%、10.9%和17.1%.随氮输入量增加,表层土壤pH值逐渐下降,4种N输入处理的表层土壤pH（KCl）分别为3.85、3.84、3.80和3.75;随氮输入量增加,淋溶液中无机氮、NO₃^-和H⁺逐渐增加.氮沉降可促进针叶林红壤的有机氮矿化,加速养分淋失和土壤酸化.