玉米植株冠层截留分异特征及其影响因素

基于研究区实际降雨频率,采用人工模拟降雨法对玉米全生育期冠层截留量、茎秆流量和穿透雨量进行测定,分析叶面积和降雨强度对玉米植株冠层截留分异特征的影响。结果表明:不同生育期,玉米冠层截留率平均为8.42%,茎秆流率平均为35.38%,穿透雨率平均为56.19%;不同降雨强度,玉米冠层截留率平均为7.53%,茎秆流率平均为26.79%,穿透雨率平均为65.68%。冠层截留量、茎秆流量和穿透雨量与雨强呈极显著线性正相关关系,冠层截留量和茎秆流量与叶面积之间呈极显著正相关直线关系,而穿透雨量与叶面积之间呈极显著线性负相关关系。     

Effects of acidic deposition on soil ecosystems under forest in the Chongqing region of China

The effects of acidic deposition on soil ecosystems under temperate coniferous forest in the Chongqing region of China were investigated from 1993 to 1994. Precipitation, throughfall, stemflow, soil solutions, and soil samples were collected to estimate the acidification of soil ecosystems through the changes of their chemical components. The concentrations of ion species in the throughfall and stemflow under masson pine forest in Mt. Zhenwu were higher than those under mixed coniferous forest in Mt. Jinyun and under camphor tree forest in Laojundong, suggesting that Mt. Zhenwu is located in the vicinity of the Chongqing center and that it allowed the canopy of masson pine to intercept air pollutants. However, the level of aluminum dissolution into soil solutions was relatively low under masson pine forest in Mt. Zhenwu in spite of the low pH in the stemflow.     

祁连山青海云杉林冠降雨再分配特征及影响因素

以祁连山排露沟小流域青海云杉林为研究对象,2015年5—9月观测了34场降雨的林外降雨量、穿透雨量和树干茎流量,并同步观测了相关的林外气象因子,分析了青海云杉林冠降雨再分配特征及影响因素。结果表明:(1)青海云杉林的总穿透雨量、树干茎流量和截留量分别为275.9,1.8,90.0mm,分别占总降雨量的75.04%,0.48%和24.48%,并在不同降雨量等级之间存在差异。(2)冠层降雨再分配各组成要素(穿透雨、树干茎流、林冠截留)与降雨量、降雨历时、10min最大雨强、空气相对湿度呈极显著的相关性。随着降雨量和降雨历时的增大,穿透雨量和树干茎流量均不断增大,而穿透雨率、树干茎流率和截留量(率)均逐渐趋于稳定。(3)青海云杉林内产生穿透雨和树干茎流的临界降雨量分别为0.8mm和9.6mm。因此,气象因素是影响冠层降雨再分配的重要因素之一。     

模拟降雨条件下作物植株对降雨再分配过程的影响

为系统测定玉米（Zea mays L.）、大豆（Glycine max）、谷子（Setaria italica）和冬小麦（Triticum aestivum Linn.）不同生长阶段的穿透雨、茎秆流和冠层截留,研究采用室内模拟降雨法测定了不同降雨强度、不同叶面积指数作物冠下穿透雨和茎秆流,采用喷雾法测定了作物不同生长阶段的冠层截留。对其进行了量化分析,并探讨了3者与作物叶面积指数和降雨强度的关系。结果表明：在40和80 mm/h降雨强度下降雨30 min,玉米、大豆、谷子和冬小麦冠下穿透雨率分别平均为65.15%、85.52%、80.05%和72.18%;在40和80 mm/h降雨强度下降雨10～20 min,4种茎秆流率分别平均为34.59%、13.58%、19.42%和26.34%;在0.3 mm/min喷雾强度下,作物冠层截留量相对较小,冠层截留率分别为0.26%、0.90%、0.53%和1.48%。随作物生长,穿透雨量逐渐降低,茎秆流量和冠层截留量逐渐增加。降雨强度与穿透雨量和茎秆流量呈正相关关系,但是2者占总降雨量的比例与降雨强度关系不显著（p＞0.05）。随着作物生长,穿透雨冠下空间分布由均匀逐渐趋向于不均匀,具有趋于向行中汇集的趋势。该研究揭示了黄土高原地区主要作物对降雨的再分配作用特征,可为农田水分有效利用和坡耕地土壤侵蚀防治提供理论依据。     

桉树人工林冠层淋溶水质特征初步研究

为探讨桉树人工林冠层对降雨水质的影响过程与特征,采用连续分程式林内雨收集系统采集水样,研究了6种不同林分人工林对冠层穿透水和树干径流水浊度、色度、pH值、化学需氧量(COD)等的影响.结果表明,在淋溶的第1阶段,3年生桉树人工林冠层穿透水(穿透雨深O～10mm)的浊度、色度、pH值、COD等4个水质参数的值分别为149.9 NTU、55度、4.97和85.5 mg/L,树干径流(径流量0-600ml)的4个水质参数值分别为192.8NTU、153度、4.76和117.8 mg/L,3年生桉树对林内雨水质的影响大于7年生杂交相思林、13年生马尾松林和软阔林.不同林龄桉树对林内雨水质的影响存在显著差异,1年生桉树林的最小,3年生的最大,7年生的居中.6种不同林分森林对林内雨水质的影响随淋溶的不断进行由强变弱.同一林分人工林其冠层穿透水水质优于树干径流.     

岷江上游油松与华山松人工混交林对降雨的截留分配效应

人工油松与华山松混交林是岷江上游区域主要的群落类型，采用水量平衡的方法，研究了混交林林冠截留量、穿透量、树干茎流量等指标。通过混交林对24场降雨分配的定位观测，结果表明林冠截留量83．47mm、穿透量81．43mm、茎流量2．00mm，分别占同期降雨量的50．o％，48．8％，1．2％；幂函数方程能较好地拟合林冠截留量与林外降雨量之间的关系，而线性方程能较好地拟合穿透雨量、树干茎流量和林外降雨量之间的关系。结果表明恢复重建后的人工油松与华山松混交林生态系统在水源涵养、水土保持上效果明显。     

降雨特征对南亚热带马尾松人工林降水分配格局的影响

探究马尾松人工林降雨特征对降水分配格局的影响,为南亚热带人工林经营管理提供科技支撑。依托广西友谊关森林生态系统国家定位观测研究站降水分配观测场,采用野外定位研究方法,以30年马尾松人工林为研究对象,观测了2018年1—12月的林外降雨、林内透流、干流和冠层截留。结果表明:研究区年降雨总量1303.6 mm,马尾松林的透流、干流及截留量分别占同期降雨的60.9%,0.4%,38.7%。产生透流和干流的最小雨量分别为0.4,2.2 mm。4个降雨特征指标中(雨量、雨强、历时和2次降水间隔时间),降雨量在马尾松降水格局分布中影响最大,雨强和历时对透流量、透流率、干流量、冠层截留量及冠层截留率均有显著影响,而2次降水间隔时间仅对透流量、干流量和冠层截留量有显著影响。SPSS多元线性回归分析表明,3个冠层水文分量对降雨特征的响应并非同步,降雨特征对林内透流和截留的影响大于干流。     

玉米冠层对喷灌水量再分配影响的田间试验研究

为了确定喷灌水量通过作物冠层时的分配规律，定量评价作物冠层对喷灌水利用率的影响，该文采用水量平衡法对喷灌条件下的玉米冠层上部、棵间、茎秆下流及冠层截留水量进行了田间观测。试验结果表明，喷灌水经玉米冠层再分配后所形成的棵间和茎秆下流水量分别占冠层上部水量的45.4%和43.0%。截留水量空间分布变化较冠层上部、棵间和茎秆下流水量为大，均值为3.6 mm，变异系数Cv平均值为0.5。由相关分析知茎秆下流水量和棵间水量均随冠层上部水量的增加而线性增加，但茎秆下流水量与冠层上部水量的关系更为密切。冠层上部水量、叶面积和株高对截留量的影响较小。     

甘蔗冠层对降雨再分配的影响

[目的]研究作物植被对于土壤侵蚀的防治作用,为砖红壤区土壤侵蚀预报模型的建立提供作物参数。[方法]通过室内人工模拟降雨试验,测定了甘蔗不同生育期不同降雨强度条件下的穿透雨量、茎杆流量和冠层截留量,分析叶面积指数对于降雨再分配的影响。[结果]穿透雨量、茎杆流量和冠层截留量分别从甘蔗幼苗期的94.7%,5.1%,0.3%变化为成熟期的49.4%,47.3%和3.4%。[结论]叶面积指数与穿透雨量呈显著负线性相关,与茎杆流量和冠层截留量呈显著正线性相关。     

黄前水库上游生态修复区典型植被林冠层水文效应

利用森林水文与水量平衡原理,采用固定标准地方法,对山东省泰安市黄前水库上游水土保持生态修复区典型植被类型的林冠层水文效应进行了研究。结果表明:①在P=18 mm的降雨条件下,生态修复区内不同树种林冠对降雨截留量的排序为油松>赤松>侧柏>麻栎>刺槐,树干径流量和林内穿透雨量没有发现有类似的规律,针叶林比阔叶林的林冠截留量大。②不同造林密度对林冠截留量的影响总体趋势为造林密度越大林冠截留量越多,反之林冠截留量就越少;林内穿透雨量与林冠截留量的变化规律相反。③不同郁闭度林分与不同造林密度的林分对降雨的再分配规律相同。④不同混交方式的林分对降雨的截留量排序为松刺栎混交>油松>松栎混交>松刺混交>麻栎>刺槐;树干径流量和林内穿透雨量的规律不明显。⑤生态修复区内典型植被林冠截留量在降雨量较小时(P=4.50 mm)截留作用很明显,林冠截留率较大;但随着雨量增加,树干径流量逐渐增大,林冠截留率呈减小趋势。     

北京密云油松人工林对降水及其营养元素含量的影响

对北京密云水库库西油松人工林的林冠截留、穿透降水和树干茎流的观测和分析结果表明，单次降雨过程中的林冠截留量与林外降水量呈幂函数关系，而穿透雨量和树干茎流量跟林外降水量皆呈线性相关关系，它们占林外降水的比例分别为7．23％～87．39％，12．56％～91．58％和0．007％～1．77％。环境状况、气象条件和降水特性的不同是造成同一地区大气降水化学性质差异的主要原因；降水透过油松林冠层后，穿透降水和树干茎流中元素含量都有不同程度的增加。穿透降水中各元素含量变化均与降水时间间隔呈正相关，而与降雨强度和降水量呈负相关；除N外，树干茎流中P，K元素含量与降水特性的关系与穿透降水的相同。     

中亚热带杉木人工林和米槠次生林树干茎流和穿透雨磷的动态特征

磷(P)伴随树干茎流和穿透雨输入到森林,成为补充亚热带森林生态系统P流失的一个重要途径,但其在不同类型生态系统中的动态特征缺乏必要的关注。以中亚热带杉木人工林和米槠次生林为研究对象,通过测定2015年6月至2018年8月间树干茎流和穿透雨中P浓度,探讨了2个林分树干茎流和穿透雨P浓度的差异、季节变化特征及影响因素。结果表明,杉木人工林树干茎流和穿透雨P浓度变化范围分别为0.002～0.026,0.003～0.024 mg/L,米槠次生林树干茎流和穿透雨P浓度变化范围分别为0.003～0.024,0.003～0.031 mg/L,2个林分树干茎流和穿透雨P浓度均在夏季表现出显著差异。2个林分的树干茎流P浓度均为夏季高于冬季,杉木人工林穿透雨P浓度在季节上无显著差异,而米槠次生林夏秋季较高,冬春季偏低,树干茎流P浓度略微高于穿透雨。2个林分的树干茎流量在4个季节均具有显著差异,米槠次生林均高于杉木人工林,而穿透雨量在季节上无差异。杉木人工林P浓度与树干茎流量和穿透雨量均呈负相关关系,而米槠次生林P浓度与树干茎流量和穿透雨量均呈正相关关系。表明不同林分林冠结构和形态学特征的差异能显著影响亚热带森林生态系统降水中P的再分配。研究结果为深入认识森林生态系统P随水文过程的动态特征提供基础数据。     

基于修正的Gash模型模拟中亚热带常绿阔叶林降雨截留过程

于2016年和2017年的5—9月期间收集研究区磨盘山国家森林常绿阔叶林的26场降雨数据,并对其林冠截留和降雨分配过程进行分析,结合研究期间的气象数据和林地调查资料,运用修正的Gash模型对其降雨截留过程进行模拟。结果表明:研究期间大部分为低雨强、低历时、中雨级的降雨;大气降雨量、穿透雨量、树干茎流量、林冠截留量分别为994.07,562.90,16.90,406.40mm。根据修正的Gash模型得出穿透雨量、树干茎流量、林冠截留量相对应的模拟值为548.63,21.75,403.28mm,与实测值相比,三者的相对误差分别为2.60%,22.29%,3.34%。总体来说,修正的Gash模型适用于拟合中亚热带地区常绿阔叶林降雨截留过程。对模型中出现的相关参数(c、P_t、S、S_t、、)进行敏感性分析,得出6个参数对林冠截留量模拟结果的影响顺序为cSS_tP_t。     

黑龙江省东部山地樟子松人工林生态系统水化学特征

对黑龙江省东部山地樟子松人工林(P inus sy lvestr is var.m ongolica)生态系统的大气降水、穿透水、树干径流和枯透水中的pH值、溶解氧、浊度、电导率、氧化还原电位、钾、钠、钙、镁、铜、锌、锰、铁等水质指标进行了观测,结果表明:大气降水经过林冠层后,水化学特征发生了明显变化,pH逐层降低,经过枯枝落叶层后,水质的酸化得到了缓解,说明樟子松人工林的枯枝落叶层对水质酸化有很好的缓冲作用。穿透水、树干径流和枯透水的COND变化趋势相同,且各月树干径流和枯透水的COND平均值均高于穿透水和大气降水。枯透水各月ORP的平均值明显低于大气降水和树干径流,可见樟子松人工林的枯枝落叶层对ORP值的降低有很好的作用。樟子松人工林对于增强水中微量元素F e和M n含量也有很好的作用。     

模拟降雨条件下玉米植株对降雨再分配的作用

为了辨明成熟期玉米对降雨的再分配作用,有效地防治区域水土流失,采用人工模拟降雨的方法,就川西低山丘陵区成熟期玉米植株对降雨的冠层截留量、茎秆流量和穿透雨量的作用进行了研究。结果表明:冠层截留率平均为7.5%,茎秆流率平均为28.8%,穿透雨率平均为63.7%。随着降雨强度的增加,单位时间内玉米冠层的截留量呈增加趋势,但随着玉米植株的叶面积增大,有效截留量却呈减少趋势,株高和角度对它的影响较小。随着叶面积和降雨强度的增加,茎秆流量呈增加趋势,角度影响较小。随着叶面积的增加,穿透雨量呈减少趋势;而随着降雨强度的增加,单位时间内穿透雨的数量呈增加的变化趋势,株高影响较小。     

The effects of organic carbon on acid rain in a temperate forest in Japan

From recent studies, we noticed that stemflow had an acidity that differed from that of precipitation or throughfall. Organic substances, supplied from the tree surface, would be one of the factors that modifies the acidity of rain. The objectives of this study were to determine the DOC concentration and to clarify the influence of dissolved organic carbon (DOC) on acidity in precipitation, throughfall and stemflow. Throughfall and stemflow were measured in sugi [Cryptomeria japonica D. Don], hinoki [Chamaecyparis obutusa Endl.] and kojii [Castanopsis cuspidata (Thumb.) Schottky.] stands. All samples were analyzed for their pH, electric conductivity (EC), major inorganic anions and cations and DOC concentration.The annual average of DOC was highest in stemflow, and that of throughfall and precipitation were one-third and one-tenth of stemflow, respectively. The averages of DOC in stemflow in two coniferous, sugi and hinoki stands, were higher than that of broadleaved kojii stand. DOC concentration was low in summer and high in winter in all stands. In Stemflow, pH and DOC were negatively correlated, while EC and DOC in stemflow were positively correlated in all stands. However in throughfall, there was no evident relationship between pH, DOC and EC. This relationship was not explained by the cause of organic acid.     

重庆缙云山酸沉降背景下针阔混交林水化学特征初步研究

选取三峡库区缙云山小流域针阔混交林作为研究对象,对其大气降水、穿透雨、树干茎流、地表径流等水文过程中的pH值及Na+、K+、Ca2+、Mg2+等离子含量进行研究,结果表明:(1)大气降水pH值为5.31,呈酸性,已属于酸雨范围(pH<5.65)。相对于大气降水,针阔混交林穿透雨和树干茎流离子含量均大幅增加。穿透雨和树干茎流中,Mg、Cu元素的变异系数均小于大气降水,而K、Zn和Mn均大于大气降水。地表径流中Ca元素含量最高,为16.416mg/L,Mn元素含量最低,几乎检测不到。各元素含量排序为:Ca>K>Na>Mg>Zn>Fe>Cu>Mn。地下径流中,Ca元素是含量增加最多的养分元素,各元素含量排序为:Ca>K>Na>Mg>Zn>Cu>Fe=Mn。(2)Cu元素在穿透雨和树干茎流中均出现了负淋溶,其余各元素浓度均有所增加。如果林木长期处于酸雨逆境下,将会导致部分营养元素大量流失,并最终造成林木营养亏损且影响其生长。     

Nutrient concentrations and acidity in ferralitic soil under perennial cropping, fallow and primary forest in central Amazonia

The long‐term productivity on the acidic, nutrient‐poor upland soils of central Amazonia depends to a large extent on the chemical soil fertility as influenced by vegetation type and management. We compared soil and soil solution data from permanent cropping, fallow and primary forest on a Xanthic Ferralsol in central Amazonia to evaluate changes of soil fertility following forest conversion, agricultural use at different intensities and setting aside agricultural land. The agricultural systems included a perennial polyculture at two fertilizer inputs and a monoculture plantation. Soil and soil solution were collected to 2 m depth, and the soil solution was monitored over 2 years. Both soil and soil solution data showed decreasing soil fertility in the sequence: monoculture and polyculture at large input, polyculture at small input, forest and fallow. The soil solution data were more sensitive to effects of systems and fertilizer inputs on subsoil fertility. Fractionation of the N in the soil solution showed a larger proportion of dissolved organic N in the N‐poor fallow soil than in the soil under forest and agriculture. The soil under fallow, forest and low‐input agriculture had larger exchangeable acidity than that under high‐input agriculture, but the Al concentrations in the soil solution were very small because there were few cations with which to exchange and less nitrification. In high‐input agriculture, pronounced acidification peaks in the topsoil solution followed fertilization. The comparison of soil and soil solution data explained why the spontaneous vegetation thrives at very large exchangeable acidity in these soils, whereas agricultural systems often depend on liming to reduce the concentration of toxic Al in the soil.     

Amount and chemical element content of rhizomorphs in the stemflow and throughfall areas of beech stands on different soil types

Rhizomorphs of Armitlaria mellea Karst s.l. were collected in the stemflow and throughfall areas of beech stands on four soil types in Hungary in order to compare their chemical element contents. The amount of rhizomorphs found in the samples increased with decreasing pH of the soil types as well as with decreasing pH caused by the influence of stemflow water. Least rhizomorphs were collected in the Ranker, whereas most were found in the stemflow areas of the pod- zolized Brown Earth. Rhizomorph and beech root samples, collected for comparison, showed highly significant differences in their chemical element contents. Rhizomorphs contained less B, Fe. Ga, Li, Mg, Mn, Ti and V, but more Cd, Co, P, Pb, Si and Zn in all soil types than comparable beech root samples. Remarkable was the high Pb content of rhizomorphs, which is not characteristic of mushroom fruiting bodies collected in unpolluted areas.     

Wasserhaushalt und Bodenwasserverteilung bei einer Futtermaiskultur in Südchile

Water balance and distribution in the soil on maize in southern Chile A water balance on maize in a Dystrandept in southern Chile was determined. With raingauges and stemflow rings the amount of rainfall was divided into throughfall, stemflow and interception. The variation with time of the water content in the soil was determinated by tensiometers and gypsum-blocks located in the soil in and between plant rows. The water distribution on the soil surface was very heterogeneous depending on the plant development. The stemflow increased with plant growth and it is the principal factor of the irregular distribution of water in the soil profile. In the plant rows and up to a medium soil depth the matrix potential was greater than between rows. Small precipitations only have a significant effectiveness on the soil because of stemflow.