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1.
河北省太行山4种经济林林冠层的水文效应 总被引：1，自引：1，他引：1
[目的]探索河北省太行山区4种经济林林冠层的水文效应,揭示其水源涵养功能。[方法]选取位于石家庄市西南部山区的核桃、苹果、杏、樱桃成林,雨量筒测定穿透雨量,树干缠绕法测定树干径流量,分析林冠层水文效应。[结果] 4种经济林的林内穿透雨量、树干径流量均随林外降雨量增加而增大;林外降雨量达到45.1 mm之前,林冠截留量随之增加而增大,之后增大趋势减缓;次降雨量在14.3～29.5 mm时,4种经济林的林冠截留作用最大,截留量占比均在20%以上;林外降雨量一定的情况下,4种经济林林冠层对降雨的截留量有较大差异,其排序为:樱桃苹果核桃杏,与郁闭度大小排序一致,林内穿透雨量与截留量排序相反;树干径流量排序为:樱桃杏核桃苹果,与平均地径大小排序基本一致。[结论] 4种经济林林冠层对降雨的再分配作用明显,林冠截留作用主要与林外降雨量有关,受林分类型、树冠结构特征如郁闭度、树木地径等的影响。 相似文献
2.
《水土保持研究》2020,(3)
为探讨苏南丘陵区毛竹林林内冠层水文特征,准确揭示冠层水文动态变化规律。2013年1月到2014年12月连续两年对苏南丘陵区毛竹林(phyllostachy edulis)林内水文效应进行了定位监测,使用自制装置收集树干径流、集水槽收集穿透雨、雨量筒收集林外降雨。研究不同的降雨量等级、降雨强度等级下,树干径流、穿透雨和林冠截留随降雨特征变化规律,并建立了回归模型,通过降雨量、相对湿度、降雨强度、风向、空气温度、相对湿度、叶面积指数定量分析了影响林冠截留的主要因素。结果表明:研究期内苏南丘陵区毛竹林外累计降雨量为2 419.1 mm,林内累计穿透雨量、树干径流量、林冠截留量分别占同期降雨量的58.70%,6.14%,35.16%;降雨量与穿透雨量、树干径流量呈现极显著线性关系,与林冠截留量的线性相关性较显著;毛竹林生长旺季月平均叶面积指数不断增加的同时,各月林冠截留总量随之增加,月平均林冠截留率整体呈下降趋势。研究区毛竹林林冠部分和树干的持水能力分别为0.38 mm,0.1 mm,且降雨事件中形成树干径流的最小雨量为1.30 mm。通过相关性分析得到影响毛竹林林冠截留主要气象因子为降雨量和降雨强度。研究可为苏南丘陵区毛竹林降雨再分配特征研究提供科学的数据支撑,为毛竹林集约发展提供理论基础。 相似文献
3.
黄前水库上游生态修复区典型植被林冠层水文效应 总被引：2，自引：0，他引：2
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。 相似文献
4.
对冀北山地落叶松桦木混交林、山杨桦木混交林、油松蒙古栎混交林3种典型林分林冠层降水分配进行了研究。结果表明：在观测期间,随着降雨量的增加,穿透雨量、径流量和林冠截留量都增加,林冠截留率降低;3种林分穿透雨量分别为115.31,115.08,125.94mm,分别占林外降雨总量的68.94%,68.81%,75.31%;3种林分单株树干径流量分别为4.35,5.90,6.24mm,分别占降雨总量的2.56%,3.47%,3.67%;可用线性回归方程来分别拟合穿透雨、树干径流、林冠截留量与林外降雨间的关系,均取得较好结果。引用林冠截留概念模型,能够较好地预测冀北山地森林生态系统降雨的林冠截留特征。 相似文献
5.
以小兴安岭原始红松林为研究对象,通过97场的降雨测定,对原始红松林的降雨截留分配效应进行系统研究。结果表明:原始红松林在生长季内的林冠截留量为98.68 mm,占同期降雨量的19.61%,是次生白桦林的1.3倍。与全国其他森林类型的平均林冠截留率（11.4%～36.5%）相比,原始红松林的林冠截留率处于中等水平。原始红松林在生长季内的穿透雨量和树干径流量分别为395.77和8.78mm,分别占同期降雨量的78.65%和1.74%。与次生白桦林相比,其穿透雨量减少,而树干径流量增加。统计分析表明,原始红松林的林冠截留量、林内穿透雨量和树干径流量与林外降雨量之间均呈现紧密的三次多项式函数关系（p<0.01）,而次生白桦林的林内穿透雨量与林外降雨量之间却呈现良好的直线关系（p<0.01）。最后,对影响林内穿透雨和树干径流的因子进行筛选和分析,为研究针阔混交林的降雨分配效应提供重要参考。 相似文献
6.
华北土石山区油松林对降雨再分配的影响 总被引：3，自引：0，他引：3
森林对大气降雨的再分配有着重要的作用,2010年通过对河北省木兰国营林场油松林穿透降雨、冠层截留量和树干径流的观测,分析了华北土石山区油松林降雨再分配的特征。结果表明:油松林的穿透降雨量、冠层截留量和树干径流量分别占大气降雨量的67.07%,29.79%,3.10%。油松林冠层穿透降雨量和树干径流量与林外降雨量呈明显的线性关系(R2=0.986,R2=0.893),林冠截留量与降雨量成幂函数关系(R2=0.765);根据回归方程,当林外降雨量大于0.264mm时,可发生穿透降雨,当林外降雨量大于4.89mm时,可发生树干径流;林冠在降雨再分配过程中起着主要的作用,在空间和时间上都进行了再分配。 相似文献
7.
不同宽度硬头黄竹林河岸缓冲带对地表径流的拦截效应 总被引：1，自引：0，他引：1
利用2008年河岸缓冲带硬头黄竹人工林的降雨量、穿透降雨量和树干径流量来计算林冠层截留量,并在冬、夏两季分别对林内枯落物和取样土壤测定最大持水能力,建立5m至40m不同缓冲带宽度的简易径流场观测地表径流量.结果表明:全年林冠截留总量为315.6 mm,占全年降水量的32.4%,林冠截留量随着降雨量的增加而增加,但林冠截留率反而减小,选取24组不同雨量级的降雨量(P)与林冠截留量(I)数据进行拟合,方程为:I=0.7791P~(0.78).硬头黄竹林内枯落物生物量为2.87 t/hm~2,其最大持水量为9.13 t/hm~2,是枯落物自身干质量的3.2倍,但由于>10 mm的降雨在时间分布上具有连续性,枯落物对降雨的截留效应明显被削弱.实际截留量只占全年降水量的9.2%.硬头黄竹林对林内土壤物理性质起到了明显的改善作用,土壤容重随着土壤深度的变浅而减小,加快了地表径流的人渗速率,土壤的最大截留能力为497.36 t/hm~2.地表径流量随河岸缓冲带宽度增加而减小,20m宽的河岸缓冲带就可截留40.7%,而当缓冲带宽度继续增加,截留效率并没有明显变化. 相似文献
8.
《水土保持研究》2015,(5)
为了探究落叶松林对降雨再分配的过程,通过对木兰围场国有林场管理局北沟林场内落叶松林进行穿透降雨、冠层截留和树干径流3个方面进行了监测,结果表明:(1)穿透雨量和林冠截留占林外降雨量的比例比较大,树干径流量的比例则非常小,分别为59.44%,39.20%,1.36%;(2)穿透雨量和林外降雨呈现线性关系(R2=0.988 6),林冠截留量与林外降雨量也具有明显的幂函数关系(R2=0.755 9),树干径流与林外降雨量具有明显的线性相关关系(R2=0.755 9),并且都达到了极显著水平(p0.01);(3)根据穿透雨与林外降雨的方程,当林外降雨量高于1.81mm时会产生穿透雨。依据林外降雨与树干径流的方程,当林外降雨高于5.18mm时会产生树干径流。林冠在降雨再分配过程中起到了很重要的作用,形成了二次降雨。 相似文献
9.
冀北山地阔叶林对降雨再分配的影响 总被引：1，自引：1，他引：0
[目的]探讨冀北山地阔叶林林冠层的穿透降雨、冠层截留和树干径流对降雨再分配的影响,为该地区的森林建设、森林结构调整提供依据。[方法]利用SPSS专业统计分析软件对林地降雨的数据进行相关性分析和回归分析。[结果]林分的穿透雨占的比例是最大(占到总比例的70.22%),林冠截留其次(为28.20%),而树干径流占得比例最小(为1.58%);穿透雨量与林外降雨量有比较好的线性关系(R^2=0.997 9),林分在降雨比较小的时候是不会有穿透雨的,当林外降雨量达到0.78mm时开始出现穿透雨。林冠截留在降雨的再分配过程中占有很重要的作用,林冠截留量与林外降雨量有明显的幂函数关系,达到了极显著水平(p<0.01)。树干径流量与林外降雨量呈现正相关的关系(R^2=0.9703),阔叶树林在降雨达到4.88mm时才会出现树干径流,但是树干径流具有一定的时滞性,而时滞性的大小和林木本身及雨量的强弱都有很大的关系,当叶面积指数较小,并且枝干夹角成45%,林木表面光滑则形成比较容易。[结论]林冠层对降雨的再分配过程有重要影响,冀北山地阔叶林林冠层的水文效应与森林健康发展具有一定的关系。 相似文献
10.
大兴安岭几种典型林分林冠层降水分配研究 总被引：4，自引：0，他引：4
对大兴安岭7种典型林分林冠层降水分配进行了研究,结果表明,2007年5-9月,大气总降水量为236.62 mm,平均每次降雨量11.27 mm;随着降雨量的增加,穿透雨量、茎流量和林冠截留量都增加,林冠截留率降低;7种林分穿透雨量分别为151.48 mm,156.16 mm,141.40 mm,162.11 mm,182.35 mm,148.69 mm,156.29mm,分别占林外降雨总量的64.02%,66.0%,59.76%,68.51%,77.06%,62.84%,66.05%;7种林分单株树干茎流量分别为4.99 mm,2.45 mm,0.82 mm,1.28 mm,3.30 mm,2.94 mm,1.67 mm,分别占降雨总量的2.11%,1.04%,0.35%,0.54%,1.39%,1.24%,0.71%;以线性回归方程来拟合穿透雨(y)和林外降雨(x)之间的关系最好;树干茎流与林外降雨的关系用线性回归方程拟合较好,但是树干径流与林外降雨之间关系不如穿透雨与林外降雨之间关系紧密;林冠截留量与降雨量之间存在紧密的正相关关系. 相似文献
11.
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
15.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
16.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献
17.
Y. Bashan J. J. Bustillos L. A. Leyva J.-P. Hernandez M. Bacilio 《Biology and Fertility of Soils》2006,42(4):279-285
Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several
photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene.
This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments
for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference
in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless
of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots.
Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production
or the positive response of the plants towards A. brasilense Cd inoculation. 相似文献
18.
Dhritiman Ghosh Velusamy Srinivasan Olli H. Tuovinen Aaron Peacock Mark Radosevich 《Soil biology & biochemistry》2009,41(6):1331-1334
We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg−1 buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg−1 in conditioned and control soil, respectively. The results demonstrate that BioSep® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation. 相似文献
19.
Pilar García Juan-Vicente Monte Carlos Casanova Consuelo Soler 《Genetic Resources and Crop Evolution》2002,49(1):103-109
Arbitrary oligonucleotides were used as primers to amplifygenomic DNA of 48 wild Spanish populations of Agropyroncristatum, Elymus hispanicus,E. caninus,E. repens,Thinopyrum curvifolium, Th.junceum and Th.intermedium. Genetic diversity was analysedusing nineteen primers. The number of amplified products ranged from8 to 18 per primer and a total of 240 markers were scored. Differentlevels of intraspecific genetic diversity were found, the allogamousspecies E. repens andTh. intermedium being themost variable. Jaccard's similarity coefficients for internalmeasure within and between populations were used to produce a clusterdiagram. The results demonstrate differences in the degree ofsimilarity between taxonomic units. Interpopulational variability andinterspecific genomic relationships of these species arediscussed. 相似文献
20.
The effects of three commonly used fungicides on the colonization and sporulation by a mixture of three arbuscular mycorrhizal (AM) fungi consisting of Glomus etunicatum (Becker & Gerd.), Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, and Gigaspora rosea (Nicol. & Schenck) in symbiosis with pea plants and the resulting response of the host-plant were examined. Benomyl, PCNB, and captan were applied as soil drenches at a rate of 20 mg active ingredient kg-1 soil 2 weeks after transplanting pea seedlings in a silty clay-loam soil containing the mixed inocula of AM fungi (AM plants). Effects of fungicides were compared to untreated plants that were inoculated with fungi (AM control). The effect of mycorrhizal inoculation on plant growth was also examined by including nonmycorrhizal, non-fungicide-treated plants (non-AM control). Fungicides or inoculation with AM fungi had only a small effect on the final shoot weights of pea plants, but had greater effects on root length and seed yield. AM control plants had higher seed yields and lower root lengths than the corresponding non-AM plants, and the fungicide-treated AM plants had intermediate yields and root lengths. Seed N and P contents were likewise highest in AM control plants, lowest in non-AM plants, and intermediate in fungicide-treated AM plants. All three fungicides depressed the proportion (%) of root length colonized by AM fungi, but these differences did not translate to reductions in the total root length that was colonized, since roots were longer in the fungicide-treated AM plants. Pea plants apparently compensated for the reduction in AM-fungal metabolism due to fungicides by increasing root growth. Fungicides affected the population of the three fungi as determined by sporulation at the final harvest. Captan significantly reduced the number, relative abundance, and relative volume of G. rosea spores in the final population relative to the controls. The relative volume of G. etunicatum spores was greater in all the fungicide-treated soils, while G. mosseae relative volumes were only greater in the captan-treated soil. These findings show that fungicides can alter the species composition of an AM-fungal community. The results also show that AM fungi can increase seed yield without enhancing the vegetative shoot growth of host plants. 相似文献