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1.
混交条件下水曲柳落叶松根系的生长与分布 总被引：14，自引：2，他引：14
用土钻法调查了水曲柳、落叶松纯林及其混交林的根系分布 ,并在温室内用盆栽和床栽方法测定了混栽及纯栽水曲柳、落叶松的根系生长。野外调查结果表明 :在混交林中 ,水曲柳、落叶松根系的水平分布不同 ,在水曲柳、落叶松相邻行间和水曲柳带内 1、2行间 ,水曲柳根密度分别为 32 37 2g·m- 3 和 3130 2g·m- 3 ,无明显差异。而在水曲柳落叶松相邻行间和落叶松带内 1、2行间 ,落叶松的根密度分别为 939 4g·m- 3 和2 745 3g·m- 3 ,差异明显。水曲柳根系有向落叶松带伸展的趋势 ,而落叶松根系的分布则受到水曲柳的抑制。混交林中根系的垂直分布更加均匀 ,在水曲柳落叶松相邻行间 ,0～ 10cm、10～ 2 0cm和 2 0～ 30cm土层内根量分别占总根量的 41 9%、2 8 7%和 2 9 4%。而水曲柳纯林中分别为 6 1 0 %、31 6 %和 7 4% ;落叶松纯林中分别为 5 5 6 %、2 7 9%和 16 5 %。温室栽培实验表明 :无论盆栽和床栽 ,混栽水曲柳的根生物量和地上生物量均高于纯栽 ,尤其是≤ 2mm细根生物量增加明显 ,盆栽时增加 2 8 8% ,床栽时增加 36 5 %。而混栽时落叶松的根生物量和地上生物量均低于纯栽。水曲柳的地下 地上比较高 ,约是落叶松的 2倍。水曲柳的根生物量约是落叶松的 4～ 6倍。上述结果说明 ,水曲柳的地下竞争能力 相似文献
2.
不同造林密度马尾松人工林的根系生物量 总被引：7，自引：0，他引：7
采用全根挖掘法和土钻法,分别测定5种造林密度20年生马尾松林分平均标准木的单木和行间根系生物量,结果表明:平均标准木单木根系总生物量随林分密度的增大而减少,不同级别根系生物量的排序为根桩>粗根>大根>中根>小根,其中根桩和粗根占根系生物量构成的90%以上.行间不同径级根系生物量的排序为中根>细根>小根.不同密度对中根、小根和细根生物量呈现出随密度增加而逐渐变小的趋势.5种密度马尾松林分的根系主要分布在0～30 cm的表层土壤中,占根系总生物量的82%以上.随着土层深度的增加,不同密度林分行间根系生物量逐渐减少.数学模型拟合的结果表明,平均标准木单木各级根系生物量与林分平均胸径、平均树高及密度有较强的相关性,除了小根以外,相关系数均达到0.8以上,林分行间各级根系生物量与林分密度也表现出较好的相关性. 相似文献
3.
以龙里林场17 a三种不同密度的马尾松人工林为研究对象,采用逐层全根挖掘法和土钻法对其平均标准木和林分行间根系生物量进行研究。结果表明:马尾松根系总生物量受密度影响显著,C(25.78 t·hm-2)>B(15.77 t·hm-2)>A(12.47 t·hm-2),占根系总生物量(根桩除外)的87.8%以上的根系分布于0~30 cm的土层中,不同径级根系中,以根桩和粗根所占比例最大。林分行间根系生物量受密度影响较大,除中根外,土层深度对小根和细根分布的影响达到显著水平。水平方向,不同径级根系生物量变化趋势各异,细根和小根生物量在距离树干约1 m处达到最高,根系总生物量主要集中在距离树干0.5 m的范围内。随着土层深度的增加,不同径级根系的生物量都呈现出逐渐降低的趋势,在10~20 cm土层中,根系生物量达到最大值。 相似文献
4.
落叶松水曲柳纯林与混交林根际土壤中养分浓度的变化 总被引：3，自引：0，他引：3
在落叶松水曲柳纯林与混交林中,采集林地土和根际土,测定了氮、磷、钾浓度,目的是探讨养分条件变化在混交林增产上的作用。结果表明:混交林林地土全氮浓度和水解氮浓度与水曲柳纯林相近,但要高于落叶松纯林。水曲柳在混交林中根际土全氮和水解氮浓度与纯林中的相近,而落叶松在混交林中根际土水解氮浓度明显高于纯林中的。混交林林地土全磷和全钾浓度与两个树种的纯林相差不大。混交林林地土有效磷、有效钾浓度均高于水曲柳纯林,而且水曲柳在混交林中根际土的有效磷和有效钾浓度与纯林中的相比明显增加,分别高出44.1%~79.6%和13.5%~25.6%。这说明水曲柳在混交林中磷和钾的利用状况得到了改善。表2参15。 相似文献
5.
[目的]探讨单作系统下平欧杂种榛根系空间分布特征,揭示影响细根(吸收根,0d≤2 mm)分布的关键土壤因子,为平欧杂种榛的地下水肥高效管理提供理论参考。[方法]采用田间分层挖掘法和根系形态结构分析系统,研究平欧杂种榛根系径级构成以及垂直与水平分布特征。[结果]表明:平欧杂种榛根系主要由细根构成,其中,细根表面积和细根长度分别占测定总根系的60.8%和93.2%,表明平欧杂种榛只有维持足够庞大的细根表面积和长度才能摄取更多的养分和水分以保障正常的生长需求。垂直方向上,平欧杂种榛根系生物量密度、表面积密度和根长密度均随土层深度的增加呈先升高后降低的趋势,各根系密度参数最大值均在10～20 cm土层。水平方向上,平欧杂种榛根系生物量密度、表面积密度和根长密度均表现为随距树干基部水平距离的增加而减小,且各根系密度参数在水平距离上差异显著。细根密度的空间分布特征表明,距树干基部水平距离0～150 cm以内的0～50 cm土层为细根表面积和根长密度的集中分布区,二者分别占测定总细根的54.16%和48.83%。相关分析表明:平欧杂种榛细根表面积密度和根长密度均与土壤含水量呈极显著正相关,表明细根分布对土壤水分的响应敏感,细根"逐水性"特征明显。[结论]在平欧杂种榛单作系统下,从节水节肥的角度考虑,距树干基部水平距离0～150 cm以内的0～50 cm土层可作为土壤水肥管理的重要区域。 相似文献
6.
[目的]探明广西不同栽培区江南油杉细根生物量的空间分布共性及其对土壤水分的响应机制.[方法]以广西3个栽培区江南油杉人工幼林为研究对象,采用根系全株分层挖掘和根系形态结构分析法,定量分析江南油杉幼树不同径级细根生物量密度、根长密度和表面积密度的空间分布特征.[结果]1)江南油杉幼林期细根生物量在垂直方向上主要分布在0～... 相似文献
7.
《广西林业科学》2018,(4)
以桉树(2 m×3 m)+山毛豆(Tephrosia candida)复合经营模式为研究对象,桉树纯林(2 m×3 m)为对照,根系生物量和根长密度为测定指标,采用根系区位全挖法和土钻样点法,探索了间种山毛豆对桉树根系空间分布的影响。结果显示:间种山毛豆有利于提高桉树细根和粗根在地下部分的比例,其中细根生物量提高幅度最大,比纯林桉树提高了1.99倍;间种山毛豆对桉树细根生物量空间分布影响显著,在垂直方向上,桉树细根生物量明显下沉,各土层大小排序为20～40 cm 0～20 cm 40～60 cm,在水平方向上,桉树细根生长明显外延,各区位细根生物量大小排序为区位2区位1区位3;间种山毛豆对0～20 cm深土层的桉树根系根长密度影响显著,其中纯林桉树细根根长密度是间种模式的1.4倍,粗根是间种模式的1.9倍,而2种模式下桉树根长密度最大值均出现在20～40 cm土层;在从桉树树兜往树行中间的水平方向上,间种模式和纯林桉树中细根和粗根的根长密度变化趋势均是单峰型曲线,其中细根根长密度峰值分别出现在1.00、1.25 m位置,粗根根长密度峰值分别出现在0.75、1.00 m位置。桉树人工林间种山毛豆能有效促进桉树根系生长,特别是细根生物量明显增加;同时桉树根系出现了生长下沉和外延现象,这可能是受地下根系生态位重叠产生的树种间竞争和促进作用影响造成。 相似文献
8.
油松蒙古栎混交林细根生物量及养分现存量研究 总被引：1，自引：0，他引：1
应用固定样地调查生物量的方法,在辽宁省建平县干旱所南大山试验区进行了油松蒙古栎混交林细根生物量和养分现存量的研究。结果表明,混交林的细根生物量大于油松纯林,两树种混栽后蒙古栎能促进油松的细根生长,提高油松细根生物量在混交林中的比例;混交林细根在各土层中分布得比纯林更均匀、更合理,两树种根系生长协调;混交林细根N、P养分现存量分别是纯林的1.1倍和1.2倍,可见混交林细根具有比纯林更高的养分积累和周转能力;纯林和混交林人工林的各径级活细根和死细根养分现存量都随细根径级的增加而减少,说明≤2 mm径级的细根在细根的养分循环中起主导作用。 相似文献
9.
以铁尾矿区沙棘-桑树人工混交林为研究对象,对混交林内各层次、器官生物量以及生长期内沙棘、桑树根系分布状况进行了研究.结果表明:单位面积生物量比较为乔木层＞枯枝落叶层＞革本层.其中地被层凋落物生物量占到整个人工林总生物量的17.巧%,尚无灌木层.桑树、沙棘各器官单位面积生物量比较均为:根＞枝＞干＞叶.桑树单株生物量大于沙棘,但林分内沙棘密度高于桑树,因而单位面积沙棘生物量高于桑树.沙棘根冠比为0.72,桑树的根冠比为0.62.从单株根系生物量看,在0-40cm土层内桑树大于沙棘;40-80cm土层内沙棘大于桑树;80-100.m土层内桑树又高于沙棘.从根系分布密度来看,沙棘＜1mm细根主要分布在根桩附近0-60cm土层,60cm以下明显减少;桑树＜1mm细根在0-20cm土层内分布密度最大,20-80cm土层内较为均匀.在80.m以下才开始明显减少.桑树和沙棘存在协作与竞争共存的关系. 相似文献
10.
《林业科学》2021,57(10)
【目的】研究不同密度水曲柳人工林细根生物量对邻近树木胸径和距离的响应,为制定合理的水曲柳根系取样方案提供理论依据。【方法】在4种林分密度(Ⅰ:3 572株·hm~(-2),Ⅱ:3 128株·hm~(-2),Ⅲ:2 215株·hm~(-2),Ⅳ:1 468株·hm~(-2))的水曲柳人工林内,随机布点取样,测定0～10、10～20和20～30 cm土层吸收根(直径≤0.05 mm)和细根(直径≤2.0 mm)生物量及0～30 cm土层的吸收根总生物量和细根总生物量,并记录距取样点最近的1株和4株树的距离及胸径。采用线性回归分析,检验细根生物量与邻近树木距离和胸径的关系。【结果】0～30 cm土层吸收根和细根总生物量受林分密度影响显著,二者均在密度最小林分中最大;从林分密度Ⅰ～Ⅳ,吸收根占细根生物量的比例分别为61.6%、54.3%、52.9%和63.4%;在所有林分中,50%以上的细根和吸收根生物量分布在0～10 cm土层;在4种密度林分中,吸收根和细根总生物量与最近1株或4株树的距离均相关性不显著(P0.05),仅有密度Ⅲ林分10～20 cm土层细根生物量与最近4株树的平均距离显著正相关(P0.05);与细根总生物量相比,0～30 cm土层吸收根总生物量与邻近树木胸径之间呈现出更普遍的相关,但相关性显著水平与林分密度有关;密度Ⅰ林分吸收根和细根生物量均与最近1株树胸径显著正相关(均R~2 0.19),而密度Ⅱ林分吸收根和细根生物量均与最近4株树的平均胸径显著正相关(均R~2 0.21);密度Ⅲ林分中吸收根生物量与最近1株或4株树的胸径均显著相关(均R~2 0.16);而密度Ⅳ林分中吸收根和细根生物量与邻近树木胸径均不显著相关;在调查的3个土层中,细根和吸收根生物量与邻近树木胸径的相关性主要出现在0～10 cm土层,并呈现出与0～30 cm土层细根总生物量相似的规律。【结论】基于对不同密度水曲柳人工林细根生物量的研究结果,认为可在东北林区不同密度水曲柳人工林内灵活设置细根取样点,不必考虑与附近林木的距离,但需考虑邻近树木胸径大小的影响,在平均木周围设置取样点是可选途径。 相似文献
11.
Belowground competition in a broad-leaved temperate mixed forest: pattern analysis and experiments in a four-species stand 总被引：1，自引：0，他引：1
We investigated fine root biomass and distribution patterns in a species-rich temperate Carpinus–Quercus–Fagus–Tilia forest and searched for experimental evidence of symmetry or asymmetry in belowground competition. We conducted extensive
root coring and applied the recently introduced in situ-root growth chamber technique for quantifying fine root growth under
experimentally altered intra- and interspecific root neighbourhoods in the intact stand. In 75% of all soil cores, fine roots
of more than two tree species were present indicating a broad overlap of the root systems of neighbouring trees. Quercus trees had more than ten times less fine root biomass in relation to aboveground biomass or productivity (stem growth) and
a much higher leaf area index/root area index ratio than Carpinus, Fagus and Tilia trees. The root growth chamber experiments indicated a high belowground competitive ability of Fagus in interspecific interactions, but a low one of Quercus. We conclude that (1) interspecific root competition is ubiquitous in this mixed stand, (2) root competition between trees
can be clearly asymmetric, and (3) tree species may be ranked according to their belowground competitive ability. Fagus was found to be the most successful species in belowground competition which matches with its superiority in aboveground
competition in this forest community. 相似文献
12.
InterspecificdiffernceIntr0ducti0nFornutrientandwaterseeking,tinerootsrepresentafuncti0nallyimportantpartofthebiomassoftbresttrees.lnforeststands,wherefinero0tsaredenselvpackedinsurfaces0iI,strongcompetitionfornutrientsandwatermaybeexpectedam0ngrootIetsan… 相似文献
13.
Morphology and vertical distribution patterns of spruce and beech live fine roots (diameter ≤2 mm) were studied using a soil
core method in three comparable mature stands in the Solling: (1) pure beech, (2) pure spruce and (3) mixed spruce–beech.
This study was aimed at determining the effects of interspecific competition on fine root structure and spatial fine root
distribution of both species. A vertical stratification of beech and spruce fine root systems was found in the mixed stand
due to a shift in beech fine roots from upper to lower soil layers. Moreover, compared to pure beech, a significantly higher
specific root length (SRL, P<0.05) and specific surface area (SSA, P<0.05) were found for beech admixed with spruce (pure beech/mixed beech SRL 16.1–23.4 m g−1, SSA 286–367 cm2 g−1). Both indicate a flexible ‘foraging’ strategy of beech tending to increase soil exploitation and space sequestration efficiency
in soil layers less occupied by competitors. Spruce, in contrast, followed a more conservative strategy keeping the shallow
vertical rooting and the root morphology quite constant in both pure and mixed stands (pure spruce/mixed spruce SRL 9.6/7.7 m g−1, P>0.10; SSA 225/212 cm2 g−1, P>0.10). Symmetric competition belowground between mixed beech and spruce was observed since live fine roots of both species
were under-represented compared to pure stand. However, the higher space sequestration efficiency suggests a higher competitive
ability of beech belowground. 相似文献
14.
采用分层挖掘法,对株行距为3 m×8 m的核桃-决明子复合模式中的根生物量、总根长密度、吸收根的根长密度和根系直径等进行了调查。结果表明：核桃单作的总根长密度比核桃间作的高7%左右,且在各个土层中吸收根的根长密度都高于核桃间作,而二者的总根生物量和根系直径则差异较小。决明子单作的根系直径比间作决明子的大27.73%,但二者的根长密度和根生物量则差异不大。在核桃-决明子复合模式中,核桃总根生物量和吸收根长均占复合模式总根量的一半以上,其中,在水平方向上,决明子在树行南侧2.5、4.0 m位置根系分布最多,而树行南北1.5 m范围内则较少;核桃根系则主要分布在树行两侧1.5 m范围内。垂直方向上,核桃在30~80 cm土层中的根生物量和吸收根长分别占其总量的64.79%和61.17%,而59.54%的决明子根系分布在0~20 cm土壤中。 相似文献
15.
Kajimoto T Matsuura Y Sofronov MA Volokitina AV Mori S Osawa A Abaimov AP 《Tree physiology》1999,19(12):815-822
We assessed above- and belowground biomass and net primary production (NPP) of a mature Larix gmelinii (Rupr.) Rupr. forest (240-280 years old) established on permafrost soils in central Siberia. Specifically, we investigated annual carbon budgets in roots in relation to root system development and availability of soil resources. Total stand biomass estimated by allometry was about 39 Mg per ha. Root biomass (17 Mg per ha) comprised about 43% of total biomass. Coarse root (>/= 5 mm in diameter) biomass was about twice that of fine roots (< 5 mm). The aboveground biomass/root biomass ratio (T/R) of the larch stand was about unity, which is much less than that of other boreal and subalpine conifer forests. The proportion of fine roots in total root biomass (35%) was relatively high compared with other cold-climate evergreen conifer forests. Total NPP, defined as the sum of annual biomass increment of woody parts and needle biomass, was estimated to be 1.8 Mg per ha per year. Allocation of total NPP to needle production was 56%. The proportion of total NPP in belowground production (27%) was less than for evergreen taiga forests. However, belowground NPP was probably under-estimated because root mortality was excluded. We conclude that L. gmelinii trees invested annual carbon gains largely into needle production or roots, or both, at the expense of growth of aboveground woody parts. This carbon allocation pattern, which resulted in the construction of exploitative root networks, appeared to be a positive growth response to the nutrient-poor permafrost soil of central Siberia. 相似文献
16.
Rui-Li WANG Rui-Mei CHENG Wen-Fa XIAO Xiao-Hui FENG Ze-Bin LIU Xiao-Rong WANG Zhi-Bo WANG 《中国林学(英文版)》2013,15(1):13-23
Environmental heterogeneity is a constant presence in the natural world that significantly affects plant behavior at a variety of levels of complexity. In order to estimate the spatial pattern of fine root biomass in the Three Gorges Reservoir Area, the spatial heterogeneity of fine root biomass in the upper layer of soils (0-10 cm) in three Masson pine (Pinus massoniana) stands in the Three Gorges Reservoir Area, China, was studied in 30 m × 30 m plots with geostatistical analysis. The results indicate that 1) both the live and dead fine root biomass of stand 2 were less than those of other stands, 2) the spatial variation of fine roots in the three stands was caused together by structural and random factors with moderate spatial dependence and 3) the magnitude of spatial heterogeneity of live fine roots ranked as: stand 3 > stand 1 > stand 2, while that of dead fine roots was similar in the three stands. These findings suggested that the range of spatial autocorrelation for fine root biomass varied considerably in the Three Gorges Reservoir Area, while soil properties, such as soil bulk density, organic matter and total nitrogen, may exhibit great effect on the spatial distribution of fine roots. Finally, we express our hope to be able to carry out further research on the quantitative relationship between the spatial heterogeneous patterns of plant and soil properties. 相似文献
17.
The biomass and the spatial distribution of fine and small roots were studied in two Japanese black pine (Pinus thunbergii Parl.) stands growing on a sandy soil. More biomass of fine and small roots was found in the 17-year-old than in the 40-year-old
stand. There were 62 g m−2 of fine roots and 56 g m−2 of small roots in the older stand, which represented mean values of 608 g for fine and 552 g for small roots per tree, respectively.
In the younger stand, a total of 85 g m−2 of fine roots and 66 g m−2 of small roots were determined, representing a mean of 238 g for fine and 186 g for small roots per tree, respectively. Fine
and small root biomasses decreased linearly with a soil depth of 0–50 cm in the older stand. In the younger stand, the fine
and small roots developed only up to a depth of 30 cm. Horizontal distributions (with regard to distance from a tree) of both
root groups were homogeneous. A positive correlation in the amount of biomass of fine and small roots per m2 relative to tree size was found. Fine and small root biomasses increased consistently from April to July in both stands.
The results also indicated earlier growth activity of the fine roots than small roots at the beginning of the growing season.
The seasonal increases in fine and small root biomasses were slightly higher in the younger stand than the older stand. 相似文献
18.
Traditional methods for studying tree roots are destructive and labor intensive, but available nondestructive techniques are applicable only to small scale studies or are strongly limited by soil conditions and root size. Soil electrical resistivity measured by geoelectrical methods has the potential to detect belowground plant structures, but quantitative relationships of these measurements with root traits have not been assessed. We tested the ability of two-dimensional (2-D) DC resistivity tomography to detect the spatial variability of roots and to quantify their biomass in a tree stand. A high-resolution resistivity tomogram was generated along a 11.75 m transect under an Alnus glutinosa (L.) Gaertn. stand based on an alpha-Wenner configuration with 48 electrodes spaced 0.25 m apart. Data were processed by a 2-D finite-element inversion algorithm, and corrected for soil temperature. Data acquisition, inversion and imaging were completed in the field within 60 min. Root dry mass per unit soil volume (root mass density, RMD) was measured destructively on soil samples collected to a depth of 1.05 m. Soil sand, silt, clay and organic matter contents, electrical conductivity, water content and pH were measured on a subset of samples. The spatial pattern of soil resistivity closely matched the spatial distribution of RMD. Multiple linear regression showed that only RMD and soil water content were related to soil resistivity along the transect. Regression analysis of RMD against soil resistivity revealed a highly significant logistic relationship (n = 97), which was confirmed on a separate dataset (n = 67), showing that soil resistivity was quantitatively related to belowground tree root biomass. This relationship provides a basis for developing quick nondestructive methods for detecting root distribution and quantifying root biomass, as well as for optimizing sampling strategies for studying root-driven phenomena. 相似文献
19.
Fine root biomass in relation to site and stand characteristics in Norway spruce and Scots pine stands 总被引：8，自引：0，他引：8
Variations in fine root biomass of trees and understory in 16 stands throughout Finland were examined and relationships to site and stand characteristics determined. Norway spruce fine root biomass varied between 184 and 370 g m(-2), and that of Scots pine ranged between 149 and 386 g m(-2). In northern Finland, understory roots and rhizomes (< 2 mm diameter) accounted for up to 50% of the stand total fine root biomass. Therefore, the fine root biomass of trees plus understory was larger in northern Finland in stands of both tree species, resulting in a negative relationship between fine root biomass and the temperature sum and a positive relationship between fine root biomass and the carbon:nitrogen ratio of the soil organic layer. The foliage:fine root ratio varied between 2.1 and 6.4 for Norway spruce and between 0.8 and 2.2 for Scots pine. The ratio decreased for both Norway spruce and Scots pine from south to north, as well as from fertile to more infertile site types. The foliage:fine root ratio of Norway spruce was related to basal area and stem surface area. The strong positive correlations of these three parameters with fine root nitrogen concentration implies that more fine roots are needed to maintain a certain amount of foliage when nutrient availability is low. No significant relationships were found between stand parameters and fine root biomass at the stand level, but the relationships considerably improved when both fine root biomass and stand parameters were calculated for the mean tree in the stand. When the northern and southern sites were analyzed separately, fine root biomass per tree of both species was significantly correlated with basal area and stem surface area per tree. Basal area, stem surface area and stand density can be estimated accurately and easily. Thus, our results may have value in predicting fine root biomass at the tree and stand level in boreal Norway spruce and Scots pine forests. 相似文献
20.
Lastvears.manvrescarchaboutintcr-sPecificrclationshipofmixcdstandsforIarchandasht`crcrePeatcd,mostof\`tich,hot`cvcr,isfortheplantingtypeoflinc-bclt.Thispaperanalysisash-larchrclationshipfor26agcdartificialIarchstandmixedwithcvenagcdashinnaturalreqencration.SlTEANDMEASUREMENTMETHOl)ArtincialIarchstandmcasuredlocatcdatecologicaIcxPCrimcntstationinMaocrshanMountainForcstryFarmofNortbcastForcstryUnivcrsity'(El27'34',N45"24').LarchttasplantcdonagrcatPCaccofdescrtcdfieIdinl967t"itha… 相似文献