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1.
杉木凋落物分解速率的研究 总被引：9，自引：0，他引：9
本文通过对杉木凋落物的分解速率的研究,结果表明:凋落物枝、叶、果1年的失重率分别为22.97%、43.51%、25.22%.凋落物枝、叶和果的分解速率分别为0.291g/(g·a)、0.588g/(g·a)和0.405g/(g·a).凋落物中失去元素的重量与元素总重量的百分比呈现趋势为:钾>磷>氮>镁>钙. 相似文献
2.
[目的]研究氮沉降背景下凋落叶分解过程中钾(K)、钙(Ca)、镁(Mg)元素的释放动态,揭示森林生态系统在氮沉降持续增加背景下养分元素的循环过程。[方法]在华西雨屏区天然常绿阔叶林中设置对照(CK)、低氮(L)、中氮(M)和高氮沉降(H)4个处理,以NH4NO3为氮源,采用尼龙网袋法对凋落叶进行模拟氮沉降分解试验,研究了凋落叶分解过程中K、Ca、Mg元素浓度及残留率,探讨氮沉降对凋落叶分解过程中养分释放的影响。[结果]经过1年的分解,模拟氮沉降显著抑制了凋落叶分解过程中K元素浓度的下降,显著促进了Ca元素浓度的下降,对Mg元素浓度无显著影响。在各处理中,K元素呈净释放模式,Ca元素表现为释放-富集的交替模式,Mg元素呈富集-释放模式,模拟氮沉降未改变凋落叶分解中K、Ca、Mg元素的释放模式。分解1年后,L、M和H处理的K元素残留率分别比CK高3.91%、10.27%和13.91%,模拟氮沉降显著抑制了凋落叶分解过程中K元素的释放;L、M和H处理的Ca元素残留率分别比CK低6.39%、6.51%和15.93%,模拟氮沉降显著促进了凋落叶分解过程中Ca元素的释放;L、M和H处理的Mg元素残留率与CK差异不显著,模拟氮沉降对凋落叶分解过程中Mg元素的释放无显著影响。[结论]模拟氮沉降未改变凋落叶分解过程中K、Ca、Mg元素的释放模式,但对凋落叶分解过程中K、Ca、Mg元素的释放速率产生了不同的影响。 相似文献
3.
研究了苹果杂种实生树营养元素含量及其相互间的关系。结果表明,在栽培条件一致、树体生长发育正常的情况下,不同品系苹果树同一种营养元素含量差异很大,其中氮、磷、钾、钙、镁、铁、锌、锰、硼的含量范围分别为1．576～2．194％、0．070～0．215％、0．51～1．78％、0．52～2．97％、0．24～0．63％、0．014～0．058％、0．001～0．016％、0．007～0．052％、15．2～36．9mg／kg;养分离子被苹果树体吸收时,氮和铁、锰、硼离子间,磷和镁、锌、锰离子间,钾和钙、镁、铁、锌离子间,锌和锰、硼离子间有拮抗作用,氮和磷、钾、钙、镁、锌离子间,磷和钾、钙、硼离子间,钾和锰、硼离子间,钙和镁、铁、锌、锰、硼离子间,镁和铁、锌、锰、硼离子间,铁和锌、锰、硼离子间,锌和锰、硼离子间,锰和硼离子间有协助作用。 相似文献
4.
湿地松和火炬松苗期矿质元素含量的研究 总被引：1，自引：0，他引：1
周佑勋 《中南林业科技大学学报(自然科学版)》1986,(1)
通过对湿地松和火炬松苗木矿质元素含量的测定研究,结果表明,这两个树种对氮元素的需求量最大,其次为钾,再次为磷,而对钙、镁的需求量较少。同时表明,这两个树种对氮、磷、钾三要素的吸收量是随季节的变化而变化的。一般以六月份吸收最多,七月后逐步下降,秋季再次出现一次吸收高峰。所有这些,都为培育这两个树种苗木进行科学、合理施肥提供了依据。 相似文献
5.
1需肥特性1.1需肥量大杨梅终年常绿,生长期长,1a抽梢3次,枝叶繁茂,生长量大,果实发育期短,成熟较早,花季分化期长,因而需肥量大。据测定,每产1000kg果实要从土中吸收的营养为:氮1.4kg,磷50g,钾1.5kg,钙50g,镁160g。由于氮、磷、钾的利用率分别只有40%,20%和30%,加之肥料在土壤中的淋洗、固定和挥发,根枝叶的生长和花芽分化,杨梅的实际需肥量比果实吸收量大1倍以上。据试验研究,株产果50kg的需肥纯量为:氮130g,磷60g,钾350g,分别相当于尿素290g,钙镁磷420g,氯化钾640g。1.2需钾、镁、钙多从前述看出,杨梅树的需钾量大于需氮量,需镁量大于需磷… 相似文献
6.
以南北样带栲属树种和常绿阔叶树种(包括栲属)为试验材料,测定了栲属树种的净光合速率、叶氮和磷含量、叶厚度、比叶重和常绿阔叶树种的比叶重、叶厚度、干物质含量。通过检验叶片功能性状指标之间相关关系得到,栲属植物的单位面积最大净光合速率与单位面积叶氮含量、比叶重彼此呈正相关,单位质量最大净光合速率与比叶重、叶厚度呈负相关,同时,无论是基于面积还是基于质量叶氮和磷含量都呈正相关关系。99种常绿阔叶树种的比叶重、叶厚度、干物质含量彼此呈正相关。 相似文献
7.
(竹思)(竹劳)竹属是优先竹种,仅分布在印度东北部到孟加拉、尼泊尔、不丹和缅甸一带,其在森林生态系统的生态作用不为人知。由于凋落物质量、凋落物分解及营养释放形态的分析是了解任何系统中土壤肥力管理的基础,因此在卡查、阿萨姆和印度东北部的湿热带林中开展研究,目的是了解凋落物分解形态,研究目的如下:(1)凋落物的初期化学成分;(2)凋落物的失重和近似碳功能;(3)叶、箨凋落物的营养释放形态。用叶代技术测量思劳竹属叶和箨凋落物的分解损失。叶凋落物中含有较高浓度的氮、磷和钾,而箨凋落物中含有很高的碳、灰分和纤维素。失重以原干重来表示,并以时间呈指数下降。叶和箨指数的方程式如下:Y=175.38 e-0.3048x.,r=0.9689和Y=139.55 e-0.2674x.,箨凋落物的损失率比叶低,但它的C/N,L/N和L/P值较高。氮释放形式是两相同的,磷浓度的初期上升,而后呈下降趋势,而钾的释放则在整个分解过程发生。叶和箨凋落物中有机复合物的浓度在分解过程中下降。本文也对凋落物分解过程中保存土壤肥力的意义进行了讨论。 相似文献
8.
川中丘陵区柏木人工林养分年动态研究 总被引：1，自引：0，他引：1
本文对川中地区30年生柏木人工林枝、叶营养元素年动态变化进行了测定.结果表明,叶中养分动态可分两种类型:季节性升降型(氮、磷、钾)和稳定型(钙、镁)各营养元素含量均在生长季末较为稳定,营养诊断采样时间以10～11月为宜;枝中养分动态大致与叶同步,而变辐较小,但生长季末期各元素含量多呈下降趋势. 相似文献
9.
油茶茶枯分解及养分释放规律 总被引：1，自引：0，他引：1
为给茶枯的资源化利用提供参考,以压榨后的茶枯为试验材料,用分解袋法进行原位分解试验,探究埋深对茶枯分解及养分释放的影响。结果表明:埋于地下茶枯的分解速率明显比放置于地面的茶枯快,分解18个月后,放置于地面和埋于地下茶枯的干物质残留率分别为49.49%和31.73%。分解后期,埋于地下茶枯的碳含量及残留率显著低于放置于地面的茶枯。氮在分解的前2个月快速释放,埋于地下茶枯的氮含量高于放置于地面的茶枯;磷、钾、钙和镁表现为直接释放,放置于地面和埋于地下的茶枯元素残留率无显著差异。傅里叶红外光谱(FTIR)检测结果显示,3 420、2 926、1 739 cm~(-1)处吸收峰强度明显减弱,表明纤维素、半纤维素、淀粉和果胶等被分解;1 050 cm~(-1)吸收峰向低频位移15 cm~(-1),变为1 035 cm~(-1),表明多糖等的碳氧(C—O)键伸缩振动遭到破坏。深埋加快了茶枯的分解以及碳的释放,施用茶枯应当覆土以促进分解。 相似文献
10.
<正> 从比较三种氮肥而设计的三个大田试验采集叶样,分析叶片氮、磷、钾、钙、镁和锰的含量,试验用硫酸铵的茶叶产量比施尿素的和硝酸铵钙的高。使用硫酸铵,叶片的氮、磷、锰含量较高,而镁的含量较低。低镁高锰归因于硫酸铵具有酸化特性。试验结果表明,施尿素的效果较差,可能是氮的挥发作用损失较大,而硝酸铵钙的肥效差,可能与土壤pH值有关,这比营养元素间的拮抗直接影响更大。 相似文献
11.
叶片对植物的生长、发育和生活史的完成具有极其重要的作用,叶生物量(叶量)及其养分含量将直接影响树体对光能的接收与利用,而土壤为植物的生长发育提供了所需的养分元素。本研究对不同年龄毛竹的叶量、叶片和土壤养分含量及其相互关系进行了研究。结果表明:(1)毛竹叶量随着径阶的增大而增大。(2)5块样地中,样地1和3的毛竹叶量明显高于其他3块样地,样地4的毛竹叶量最小。(3)毛竹叶片中镁含量随着年龄的变化差异不显著(p>0.05);氮、总磷、有机磷、钾、钙含量在1度毛竹叶片与其他年龄毛竹叶片含量差异显著(p<0.05);2度以上各年龄毛竹叶间氮含量差异显著(p<0.05);毛竹叶无机磷含量仅1度竹叶与4度竹叶含量差异显著(p<0.05);叶片中的氮磷比值(N/P)随年龄增加先增大后减小;相同年龄不同径阶毛竹的叶片养分含量虽有变化却不存在显著差异(p>0.05)。(4)竹叶中氮含量与有机磷、全磷、钾、钙含量呈极显著相关(p<0.01);总磷、无机磷、有机磷含量与钙、钾含量显著相关(p<0.05);钾与钙含量呈极显著负相关(p<0.01)。(5)毛竹林土壤pH值与叶片镁含量显著负相关(p<0.05);土壤中镁含量与叶片中钙含量显著负相关(p<0.05),而与叶片全氮、总磷、有机磷、镁含量呈极显著负相关(p<0.01)。 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(1-4):399-415
Decomposition of Scots pine needle litter originating from five stands treated with different amounts of nitrogen fertilizer was measured over a 4‐year period in a mature Scots pine forest. The litter types, which differed in initial concentrations of nitrogen, phosphorus, potassium, and sulfur, but not in gross organic composition, were studied with respect to mass loss, ingrowth of total fungal mycelium, and net release of nutrients. During the first year of decomposition, rates of mass loss and ingrowth of fungal mycelium were highest in the nutrient‐rich litter. Phosphorus concentration was found to be the main factor affecting mass‐loss rate, and the rate of fungal ingrowth was positively correlated with initial nitrogen concentration. After this initial period, decomposition rates decreased, and after 4 years, accumulated mass loss and amounts of fungal mycelium were similar in all five litter types. These findings may be due, in part, to a lower rate of lignin decomposition in nitrogen‐enriched litter. Of the elements, potassium and magnesium were most rapidly lost from the litter, and their release was most pronounced during the first year. Calcium release was proportional to the loss in organic matter. Initially, the release of nitrogen and phosphorus was positively related to their concentrations in litter, however, during later stages of decomposition the differences among litter types levelled out. There was a tendency for concentrations of all elements, except nitrogen, in the different litters to approach similar levels as decomposition proceeded. Thus, after 4 years the nutrient composition of the various litter types was very similar, except for higher nitrogen concentrations in the originally most nutrient‐rich litters. The importance of the results in terms of substrate quality in fertilized as well as in non‐fertilized forests is discussed. 相似文献
13.
We measured concentrations of sodium, potassium, magnesium, and calcium in forest canopy arthropod functional groups collected from vegetation of clearcut and uncut hardwood forests at Coweeta Hydrologic Laboratory, North Carolina during 1977 and 1978. Functional groups differed significantly in concentrations of the four elements. Spiders had the significantly highest sodium concentrations, followed in decreasing order by some other predators and then herbivores. Caterpillars and sawfly larvae had the significantly highest potassium and magnesium concentrations and high calcium concentration. Detritivores had the significantly highest calcium concentrations. Our data indicate that nutrients contained in nominal biomass of canopy arthropods do not contribute significantly to litter nutrient pools. 相似文献
14.
Budget of nutrient in plant and soil, and their rates of recycling in three types of traditional agroforestry systems in mid
elevations of the western Himalaya were studied. Concentration of nitrogen and potassium was significantly higher in fruits
and leaves than in branches, boles, and litter. Grewia optiva, an important fodder tree, was found to be rich in potassium, vegetable crops in nitrogen, and weeds in phosphorus. Maximum
store of nutrients was estimated in aboveground biomass of agrihortisilvicultural system: nitrogen 532, phosphorus 40, potassium
461, calcium 400, and magnesium 298 kg/ha; it was closely followed by that in agrihorticultural system, and both these had
sbout 2-fold higher nutrient stock as compared to agrisilvicultural system. In the case of the former two systems, considerable
quantity of nutrients up to nitrogen 169, phosphorus 14, potassium 165, calcium 97, and magnesium 65 kg/ha, for example in
agrihortisilvicultural system, was recycled through debris of crops and weeds, and tree leaf litter, while the recycling rate
was almost half in agrisilvicultural system. Through ‘harvest’ potassium was depleted in the largest quantity from the system,
followed by nitrogen, magnesium, calcium, and phosphorus; much higher loss occurred through agricultural and/or horticultural
edible parts as compared to fuel and fodder biomass. For example, the loss through agricultural crops and horticultural fruits
for nitrogen in agrihortisilvicultural system was up to 75 percent and 38 percent respectively of the total annual uptake.
This heavy loss makes the system unstable from a nutrient point of view particularly for nitrogen and potassium until external
inputs are added through organic and inorganic fertilizers. Agrihortisilvicultural system is remarkably efficient in view
of biomass productivity for fuel, fodder and fruits, and also from nutrient point of view provided losses through harvest
are compensated externally. 相似文献
15.
T. Sariyildiz E. Akkuzu M. Küçük A. Duman Y. Aksu 《European Journal of Forest Research》2008,127(5):429-440
This study investigated the effects of Ips typographus (L.) damage on initial litter quality parameters and subsequent decomposition rates of oriental spruce tree species [Picea orientalis (L.) Link]. The needle litter was collected from highly damaged, moderately damaged and control stands on two aspects (north
and south) and two slope position (top and bottom) on each aspect. The litter was analyzed for initial total carbon, lignin
and nutrient (nitrogen, phosphorus, potassium, calcium, magnesium and manganese) concentrations. The variability in nitrogen
and calcium concentrations and ratios of C:N, lignin:N and lignin:Ca was significantly affected by the insect damaged levels.
While nitrogen concentrations in needle litter increased with increasing insect damage (and consequently the ratios of C:N
and lignin:N decreased), calcium concentrations decreased (and consequently the ratio of lignin:Ca increased). Aspect and
slope positions explained most of the variability in carbon, lignin, phosphorus, potassium, magnesium and manganese concentrations
and lignin:P ratio between all studied stands. Litter decomposition was studied in the field using the litterbag technique.
The litter from highly damaged stands showed highest decomposition rates followed by moderately damaged and control stands.
The mass loss rates were significantly positively correlated with initial nitrogen concentration and negatively with C:N and
lignin:N ratios. The effects of microclimate resulting from canopy damage on litter decomposition was also examined at the
same time using standard litter with the same litter quality parameters, but they showed no significant differences among
the insect damage levels indicating that alteration of the litter quality parameters produced by I. typographus damage played a more important role than altered microclimate in controlling needle litter decomposition rates. However,
changes in microclimate factors due to topography influenced decomposition rates. 相似文献
16.
Extensive variation in fractional resorption of mineral elements from plant leaves is still not fully understood. In multi-species forest stands, species leaf fall phenology and leaf constitution may significantly modify the timing of nutrient return to the soil and overall plant nutrient loss. We studied leaf fall and nutrient loss kinetics, and leaf composition in three natural, temperate, deciduous broadleaf forest stands to determine the role of timing of leaf abscission and nutrient immobilization in cell walls on nutrient resorption efficiency of senescing leaves. Nitrogen (N), phosphorus and potassium contents decreased continuously in attached leaves after peak physiological activity during mid-season. Changes in nutrient contents of attached leaves were paralleled by decreases in nutrient contents in freshly fallen leaf litter. In different species and for different nutrients, resorption of nutrients from senescing leaves proceeded with different kinetics. The maximum nutrient resorption efficiency (the fraction of specific nutrient resorbed from the leaves at the end of leaf fall) did not depend on the mid-seasonal nutrient concentration. Species with earlier leaf fall resorbed leaf nutrients at a faster rate, partly compensating for the earlier leaf fall. Nevertheless, the litter-mass weighted mean nutrient contents in leaf litter were still larger in species with earlier leaf fall, demonstrating an inherent trade-off between early leaf fall and efficient nutrient resorption. This trade-off was most important for N. Losses of the non-mobile nutrients calcium and magnesium were unaffected by the timing of leaf fall. There was large variation in the maximum N resorption efficiency among species. Correlations among leaf chemical variables suggested that the maximum N resorption efficiency decreased with the increasing fraction of cell walls in the leaves, possibly due to a greater fraction of N occluded in cell wall matrix. We conclude that species leaf fall phenology and leaf chemistry modify the timing and quantities of plant nutrient losses, and that more diverse forest stands supporting a spectrum of species with different phenologies and leaf types produce litter with more variable chemical characteristics than monotypic stands. 相似文献
17.
Nutrient changes in potting mix and Eucalyptus nitens leaf tissue under macadamia biochar amendments 总被引：4，自引：0，他引：4
A.Wrobel-Tobiszewska M.Boersma J.Sargison P.Adams B.Singh S.Franks C.J.Birch D.C.Close 《林业研究》2018,(2)
The effect of macadamia nut shell biochar on nitrogen,potassium,phosphorus,magnesium,calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experiment.The treatments combined two fertiliser rates(50 and 100% rate of the commercial mix commonly used in forestry nurseries) with eight biochar rates(0,2,5,10,20,50,80 and 100 t ha~(-1)) arranged in a randomised complete block with three replicates of four sample plants.Nutrients were quantified in the potting mix and seedling leaves at four destructive harvests 135,177,219 and269 days after planting.Biochar significantly increased nitrate-N,Colwell P,Colwell K and exchangeable Na andreduced ammonium-N,Mg and Ca concentrations in the potting mix.Seedling leaf concentrations of P,K and Na were increased by biochar application,while N remained dependent on fertiliser rate only.Mg and Ca leaf concentrations decreased in response to increasing biochar rates.Elevated nitrate-N and decreased ammonium-N concentrations suggest that biochar might have increased nitrification in the potting mix.We presumed that biochar mediated processes that reduced uptake of P and K when high doses of biochar were combined with full fertilisation.Changes in potting mix K,Na,Mg and Ca were consistent with selective adsorption of ions to biochar surfaces. 相似文献
18.
19.
Wendelin Weis Andreas Gruber Christian Huber Axel Göttlein 《European Journal of Forest Research》2009,128(5):437-445
Twenty years after the application of dolomitic limestone to a well growing, mature Norway spruce stand at Höglwald, Southern Germany an amount of magnesium equal to the input by liming has left the rooting zone. However, 80% of the applied calcium was retained by the ecosystem. A detailed biomass investigation was carried out in order to elaborate whether the stand shows any nutritional benefits and if the aboveground tree biomass represents a sink for calcium and magnesium after liming. Stem wood, bark, branches, twigs, and needles were analysed for the major nutrients. Needles showed higher calcium and magnesium concentrations and significantly lower potassium concentrations on the limed plot. Surprisingly, limed trees had significantly lower magnesium concentrations in the bark but higher concentrations in twigs and needles than unlimed trees. In addition, significantly lower concentrations for potassium, sulphur, and phosphorus were measured in the bark of limed trees, whereas the element concentrations in the wood were rather similar between the two treatments. The low potassium concentrations in bark and needles indicate an impeded potassium uptake after liming presumably due to a calcium potassium antagonism. Magnesium is probably used to compensate the relative lack of potassium. The small differences in the calculated nutrient storage of limed and unlimed trees, however, suggest that the aboveground biomass can be excluded as a relevant sink for the applied calcium and magnesium at the Höglwald site. 相似文献
20.
THE COMPOSITION OF TREE LEAVES 总被引：1，自引：0，他引：1
Tree leaves have been collected from three series of forestplots, each series with a wide range of tree species establishedon a fairly uniform soil type. The contents of sodium, potassium,calcium, magnesium, iron, manganese, silica, phosphorus, ash,carbon, and nitrogen in the tree leaves are given. The chemicalcompositions of the leaves are related to soil conditions andthe tree species selected for afforestation. When hardwood leavesare compared with softwood leaves some consistent differencesin chemical composition occur between the two groups at allthree localities. The ecological and silvicultural applicationsof foliar analysis are considered. 相似文献