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1.
《Scandinavian Journal of Forest Research》2012,27(1-4):263-271
Exchangeable Al and acidity of Swedish beech (Fagus sylvatica L.) forest soils are documented and discussed on the basis of known changes in soil chemical properties during recent decades. It is concluded that the pH and base saturation decrease, which has occurred in most forest soils of the region, has been accompanied by increases in the amount of exchangeable and soil solution Al and a greater decrease of the Ca: AI ratio, particularly in the B horizon. An adverse nutritional state now seems to prevail in most beech forest B horizons. Conditions are more favourable in the topsoil due to the formation of Al‐humus complexes which are less available to plant uptake, and in the case of very acid mor layers, a low Al content. However, in A (mull) horizons of intermediate acidity with a rather high clay content and low in humus, conditions approaching those of the B horizon may be found. 相似文献
2.
Panagiotis Michopoulos Kostas Kaoukis George Karetsos Theodoros Grigoratos Constantini Samara 《林业研究》2020,31(1):291-301
The fluxes of masses and the nutrients Ca,Mg,K,N,P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak(Quercus frainetto L.)and European beech(Fagus sylvatica L.)in a mountainous area of northeastern Greece in 2010–2015.The foliar litterfall for both species reached about 70%of the total litterfall,and was significantly higher from the other two fractions(woody and rest litterfall).The fluxes of masses and nutrients were compared between ecosystems for each fraction separately.Only one significant statistical difference was found,that of K in the woody litterfall.In addition,the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems.Likewise,the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems.In the L horizon of the forest floors,statistical differences,as a result of species effect,were found for the stocks of Ca and N.In the FH horizons,the masses and all the nutrient stocks differed significantly,as the beech plot had much higher quantities of organic matter and nutrients.These higher quantities were probably due to low soil temperatures(microclimate)and high acidity in the beech plot(species effect)that slowed down decomposition.In the mineral soils,the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons.Because of the soil acidity in the beech plot,the stocks of exchangeable base cations were significantly higher in the oak plot,whereas the other nutrient stocks did not differ. 相似文献
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Rakesh Minocha Stephanie Long Palaniswamy Thangavel Subhash C. Minocha Christopher Eagar Charles T. Driscoll 《Forest Ecology and Management》2010
Acidic deposition has caused a depletion of calcium (Ca) in the northeastern forest soils. Wollastonite (Ca silicate) was added to watershed 1 (WS1) at the Hubbard Brook Experimental Forest (HBEF) in 1999 to evaluate its effects on various functions of the HBEF ecosystem. The effects of Ca addition on foliar soluble (extractable in 5% HClO4) ions, chlorophyll, polyamines, and amino acids were studied in three hardwood species, namely sugar maple, yellow birch, and American beech. We further analyzed these effects in relation to elevation at Ca-supplemented WS1 and reference WS3 watersheds. Foliar soluble Ca increased significantly in all species at mid and high elevations at Ca-supplemented WS1. This was accompanied by increases in soluble P, chlorophyll, and two amino acids, glutamate and glycine. A decrease in known metabolic indicators of physiological stress (i.e., the amino acids, arginine and γ-aminobutyric acid (GABA), and the diamine, putrescine) was also observed. In general, these changes were species-specific and occurred in an elevation dependent manner. Despite an observed increase in Ca at high elevation for all three species, only sugar maple exhibited a decrease in foliar putrescine at this elevation indicating possible remediation from Ca deficiency. At higher elevations of the reference WS3 site, foliar concentrations of Ca and Mg, as well as Ca:Mn ratios were lower, whereas Al, putrescine, spermidine, and GABA were generally higher. Comparison of metabolic data from these three species reinforces the earlier findings that sugar maple is the most sensitive and American beech the least sensitive species to soil Ca limitation. Furthermore, there was an increase in sensitivity with an increase in elevation. 相似文献
6.
Three tree species are traditionally conserved in the traditional slash and burn agricultural system practiced for the production
of upland rice (Oryza sativa Linn.) in the Fouta Djallon region of Guinea, i.e. (Parinari excelsa [Sabine], Parkia biglobosa
[Jacq.) Benth.], Erythrophleum guinensis [G. Don.]). Sampling a chronosequence of fallow sites indicated that extractable
P; exchangeable K, Ca and Mg; cation exchange capacity (CEC) and pH all decreased over the fallow period with patterns that
differed with soil depth. Soils under the remnant Parinari excelsa and Parkia biglobosa trees had higher concentrations of
organic C; total N; extractable P; exchangeable K, Ca and Mg; total P and Ca; and CEC than did the open microsites. Extractable
P; exchangeable K, Ca and Mg; total P and Ca; and CEC were greater under Parinari excelsa than under Erythrophleum guinensis.
Intensive measurements of a single mature fallow site showed that the foliar nutrient concentration of the large trees was
not an accurate index of which microsite had the greatest accumulation of biomass and nutrients in the aboveground fallow
vegetation. The biomass and the total amounts of N, P, K, Ca and Mg in the fallow vegetation were significantly greater for
the Parinari excelsa and Parkia biglobosa microsites than for the open microsites. We conclude that although the nutrient
status of the soils decreased over the 8-year fallow period, the microsites under the large trees were generally more fertile
than the open microsites. However, there were important differences in the effects of the different tree species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Teak (Tectona grandis L.f.) is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic to severely acidic in southern China. But, there are no available and specific evidence-based nutrient management techniques. To better recognize and understand the relationship between teak tree growth and nutrient content in the foliage and soil and establish nutrient norms are critical to optimally manage these young plantations. We studied the foliar nutrient and soil chemistry in 19 representative teak plantations aged 5–8 years. Regression analysis indicated that the mean annual increment of teak volume was linearly and positively correlated with foliar N, Ca, Fe and B concentrations, with soil base saturation percentage, available P and Zn concentrations, and negatively correlated with soil Al concentration. Only if the Ca and Mg contents in soil were enhanced, could the increase in soil base saturation percentage benefit teak growth. A revised classification of low-and high-yielding stands was established by using a sorting method of principal components over 6 foliar macro and 8 micro elements in a Diagnosis and Recommendation Integrated System (DRIS). Specific DRIS norms for teak plantations in acid soils were derived. The nutrient balance of N, P, K Ca, Mg, Zn, B with Fe or Al, Ca with Mg, and Fe with Al provided a key to promote the growth of teak in acid soils. Meanwhile, soil Zn was also found as a primary trace element that affected teak growth in this study. 相似文献
9.
《Forest Ecology and Management》1997,91(1):47-52
Results from long-term fertilizer experiments on Scots pine (Pinus sylvestris) planted on old arable land in the north-eastern German lowlands demonstrate the necessity for fertilization with KMg on poorly buffered sandy soils.Applying KMg to young Scots pine increased pole production over a 60 year period by a total of 129 m3 ha−1 (26%). In other experiments the improvement was as much as 93%.KMg manuring on light soils ensures optimal K and Mg nutrition and creates the conditions for uninterrupted growth and healthy development of the plantation. On degraded soils, KMg treatment leads to improved utilisation of the low soil nitrogen supply.With increasing eutrophication due to atmospheric nitrogen, KMg fertilization overcomes the depletion of soil cations and resulting imbalance in tree metabolism.Adequate application of KMg is a prerequisite for success in underplanting with beech (Fagus silvatica) on soils with a land use classification below 30, increasing the growth in height of beech by about 30%.KMg fertilizer favours biomass production and thus the fixation of N deposited through the atmosphere by the vegetation. Thereby, KMg fertilizer use and other silvicultural measures reduce the negative effects of atmospheric N-input in forest ecosystems to a certain extent, especially the N-pollution of groundwater. However, they cannot replace the technologies to reduce the N emissions. 相似文献
10.
Differences in sensitivity to soil conditions across tree species and developmental stage are important to predicting forest response to environmental change. This study was conducted to compare elemental concentrations in leaves, stems, and roots of (1) sugar maple (Acer saccharum Marsh.) seedlings vs. mature trees and (2) mature sugar maple vs. mature American beech (Fagus grandifolia Ehrh.) in two sites that differ in soil base saturation and pH. Both sites are located in Huntington Forest, NY, USA; one site (hereafter ‘H’) has higher soil pH and Ca, Mg, and Mn concentrations than the other site (hereafter ‘L’). Sugar maple growth at H (14.8 cm2 year−1 per tree) was much greater than at L (8.6 cm2 year−1 per tree), but the growth of beech was not different between the two sites. Leaves, roots, and stem wood of mature beech trees and sugar maple seedlings and mature trees were sampled for nutrient analysis. Foliar Ca, K, and Al concentrations were positively correlated with soil elements, but Mn concentrations were negatively correlated. Sugar maple differed more than beech between sites in foliar K and Mn concentrations. Root Mg and P concentrations reflected soil chemistry differences, in contrast to foliar concentrations of Mg and P, which were indistinguishable between the sites. In sugar maple, seedlings differed more than in mature trees in nutrient concentrations in roots, especially for Mg and Mn. Although beech was not as responsive to nutrient availability as sugar maple in foliar and root nutrient concentrations, Ca and Mg concentrations in beech wood were higher in H (52% higher for Ca and 68% higher for Mg), while sugar maple did not differ between sites. Sugar maple regeneration failure on acidic soils in the same region is consistent with our finding that sugar maple seedlings were very sensitive to nutrient availability. This sensitivity could ultimately contribute to the replacement of sugar maple by American beech in regions of low pH and base cations if base cation leaching by anthropogenic deposition and tree harvesting continues. 相似文献
11.
Susana Peña-Rodríguez Alicia Moretto Xabier Pontevedra-Pombal Natalia Oro Eduardo García-Rodeja Gayoso Isabel Rodríguez-Salgado José Rodríguez-Racedo Julio Escobar Juan Carlos Nóvoa-Muñoz 《Agroforestry Systems》2013,87(6):1273-1281
Macro- (C, N, P, K, Ca and Mg) and micronutrient (Fe, Mn, Cu and Zn) reservoirs were estimated in the O (Oi+Oe+Oa) and in the A (0–10 cm depth) soil horizons of four stands of Nothofagus pumilio (lenga) from Tierra del Fuego which differ in their forestry characteristics. The type of soil layer (O and A) and the forest structure, as related to above-ground biomass storage, were assessed as a factor of variation in the nutrient reservoirs of both soils layers. Nutrient reservoirs showed similar ranges in both soil layers for total organic C (34–65 Mg ha?1), total N (1.5–3.5 Mg ha?1), rapidly available Ca (1.3–2.7 Mg ha?1) and Mg (0.18–0.36 Mg ha?1). Rapidly available K, available P, and medium-term available Fe and Cu were accumulated preferentially in A the horizons, whereas medium-term available Mn and Zn were mainly stored in the O horizons. The forest structure was not a statistically significant factor of variation on the nutrient reservoirs in the O horizons, although a legacy effect of the accumulated above-ground biomass on nutrient reservoirs in this soil layer can not be discarded. On the contrary, the pools of total organic C, total N, rapidly available K and medium-term available Cu and Zn in the A horizons varied significantly with the different forest structure. In terms of lenga forests sustainability, uppermost soils layers should be preserved as they accumulate most of the soil fertility which is essential for lenga regeneration after logging. The inclusion of the assessment of soil fertility in the management plans of the lenga forests in the ecotone of the Argentinean Tierra del Fuego is strongly recommended, as it will contribute to ensure a successful regeneration of lenga in logged areas. 相似文献
12.
Jörg Prietzel Karl Eugen Rehfuess Ulrich Stetter Hans Pretzsch 《European Journal of Forest Research》2008,127(1):43-61
Long-term (40 years) effects of two soil amelioration techniques [NPKMgCa fertilization + liming; combination of PKMgCa fertilization,
liming, tillage, and introduction of lupine (Lupinus polyphyllus L.)] on chemical topsoil properties, stand nutrition, and stand growth at two sites in Germany (Pfaffenwinkel, Pustert) with
mature Scots pine (Pinus sylvestris L.) forest were investigated. Both sites are characterized by base-poor parent material, historic N and P depletion by intense
litter-raking, and recent high atmospheric N input. Such sites contribute significantly to the forested area in Central Europe.
Amelioration resulted in a long-term increase of pH, base saturation, and exchangeable Ca and Mg stocks in the topsoil. Moreover,
significant losses of the forest floor in organic carbon (OC) and nitrogen stocks, and a decrease of the C/N ratio in the
topsoil were noticed. The concentrations and stocks of OC and N in the mineral topsoil increased; however, the increases compensated
only the N, but not the OC losses of the forest floor. During the recent 40 years, the N nutrition of the stands at the control
plots improved considerably, whereas the foliar P, K, and Ca concentrations decreased. The 100-fascicle weights and foliar
concentrations of N, P, Mg, and Ca were increased after both amelioration procedures throughout the entire 40-year period
of investigation. For both stands, considerable growth acceleration during the recent 40 years was noticed on the control
plots; the amelioration resulted in an additional significant long-term growth enhancement, with the NPKMgCa fertilization
liming + being more effective than the combination of PKMgCa fertilization, liming, tillage, and introduction of lupine. The
comprehensive evaluation of soil, foliage, and growth data revealed a key relevance of the N and P nutrition of the stands
for their growth, and a change from initial N limitation to a limitation of other growth factors (P, Mg, Ca, and water). 相似文献
13.
Foliar mineral concentration may provide a basis for monitoring the consequences of long-term environmental changes, such as eutrophication and acidification of soils, or increase in atmospheric CO(2) concentration. However, analytical drifts and inter-tree and year-to-year variations may confound environmental effects on long-term changes in foliar mineral concentration. We have characterized the relative effects of these potentially confounding factors on foliar carbon, nitrogen, phosphorus, calcium, potassium, magnesium and manganese concentrations in 118 pure beech (Fagus sylvatica L.) stands, sampled in 1969-71 and 1996-97. Interannual fluctuations of these elements were quantified in a subset of six beech stands monitored for 5 years. Intercalibration between the methods used at each sampling period for nitrogen and phosphorus analyses showed significant, but low, relative differences (0.8 and 3.3% for N and P, respectively). Based on inter-tree variability, elements could be arranged in four groups: C (constant), N and P (low variability), K and Ca (medium variability), Mn and Mg (high variability). Inter-tree coefficients of variation were 2, 6, 8, 15, 18, 22 and 27%, respectively. Year-to-year fluctuations increased in the order N, P, Mg, K, Ca, and Mn coefficients of variation of 4, 4, 7, 9, 11, 15 and 29%, respectively). Between the two sampling periods, foliar N concentration increased 12%, whereas decreases were observed for P (-23%), Mg (-38%) and Ca (-16%). Ratios of N/P, N/K and N/Mg increased by 42, 19 and 77%, respectively. These changes were larger than the interannual variations for P, Mg, N/P, N/Mg and Mg/Ca. Decreasing concentrations of P and cations were particularly marked for trees growing on acidic soils, whereas the positive N trend did not depend on soil type. Both increasing atmospheric CO(2) concentrations and acidification of forest soils could contribute to decreasing P and cation concentrations in foliage. The increase in foliar N concentration with time suggests a nitrogen deposition effect. Whatever the causes of these changes, the large shift in element ratios indicates an accelerating imbalance between nitrogen and cation status. 相似文献
14.
Rachel C. Pinho Sonia S. Alfaia Robert Pritchard Miller Katell Uguen Leovone D. Magalhães Marta Ayres Viviane Freitas Ralph Trancoso 《Agroforestry Systems》2011,81(3):235-247
Homegardens are a common feature of indigenous dwellings in the savannas of Roraima, northern Brazil. In order to evaluate the effect of homegardens on soils, samples were taken in 5 sites each in the categories new homegardens (0–10-years old), established homegardens (15–35-years old) and old homegardens (more than 40-years old) and in adjacent savanna in Araçá Indigenous Land, Roraima, Brazil. For comparison, samples were also taken in forest islands located nearby, on a different soil type, under 10-year-old forest fallows and high forest. P and K showed the greatest increases over time in homegarden soils, in comparison with levels found in adjacent savanna and under forest. Ca and Mg also increased in comparison to adjacent savanna, but levels were less than found in forest soils, most likely due to the different parent material. Zn and Fe also showed increases in homegarden soils over time. Cu and Mn levels showed little relation to homegarden age, suggesting greater effects of factors of soil formation than anthropogenic influences. Values for pH were slightly higher in homegardens than in adjacent savanna, while Al was lower, although these changes were poorly fit by regression models. Soil organic matter increased over time under homegardens, but still was lower than levels found under fallows and forest. Soil fertility improvement under indigenous homegardens can be attributed mainly to deposition of residues around dwellings, although further investigation is needed on the role of trees in accessing nutrient pools at greater depths in savanna soils. 相似文献
15.
Reclaiming sodic soils for wheat production by Prosopis juliflora (Swartz) DC afforestation in India
A green house pot trial was conducted to assess the impact of Prosopis afforestation on the productivity and fertility of degraded sodic soils in Haryana, India. Wheat (Triticum aestivum, L; cultivar HD 2329) plants were grown from seed on top soils collected from a chronosequence of 0, 5, 7, and 30-year-old Prosopis juliflora plantations established on highly sodic soils and a non-sodic reference soil collected from a local farm. The afforestation improved physical and chemical properties of surface soils by decreasing pH, electrical conductivity and exchangeable Na levels, and increasing infiltration capacity, organic C, total N, available P, and exchangeable Ca, Mg, and, K levels. The amelioration effect of the trees on top soil increased with duration of tree occupancy. Soil nutrient status under the 30-year-old plantation was higher than that of the non-sodic farm soil. The reduced soil sodicity and improved fertility contributed to higher germination, survival, growth, and grain yield of wheat plants grown on the Prosopis chronosequence soils, even surpassing the yield attained on the farm soil in the case of 30-year-old plantation soil. Sodium accumulation in the crop declined while N, P, K, Ca, and Mg uptake increased with soil plantation age reflecting the changing nutrient status of the rooting zone due to afforestation. Results confirmed that successful tree plantation may restore the productivity and fertility of highly degraded sodic soils. 相似文献
16.
《Forest Ecology and Management》2006,221(1-3):207-214
Effects of enhanced nitrogen deposition on nutrient foliar concentrations and net photosynthesis of sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifolia Ehrh) and red spruce (Picea rubens Sarg.) were evaluated at the Bear Brook Watershed in Maine (BBWM). The BBWM is a paired-watershed forest ecosystem study with one watershed treated since 1989 with bimonthly dry ammonium sulfate ((NH4)2SO4) additions at a rate of 25.2 kg N ha−1 year−1, while the other watershed serves as a reference. The (NH4)2SO4 treatment resulted in significant increases in foliar N concentrations for all three species and significant reductions in foliar Ca, Mg and Zn concentrations for American beech and red spruce. Treatment effects on foliar concentrations of other nutrients were not significant in any species. Despite higher N concentrations in all species, only treated sugar maple showed significantly higher photosynthetic rates. The non-response in net photosynthesis to higher foliar N in American beech and red spruce might be attributed to their low foliar Ca and/or Mg concentrations. Higher net photosynthetic rates in sugar maple might be explained by the higher foliar N and by the ability of this species to maintain an adequate Ca and Mg supply. Results suggested that nutrient imbalances due to inadequate supply of Ca and Mg might have counteracted a potential increase in net photosynthesis induced by higher N concentrations in American beech and red spruce. 相似文献
17.
冰冻灾害前后矿区废弃地栾树杜英混交林生态系统养分含量的比较 总被引:2,自引:0,他引:2
对冰冻灾害前后湖南湘潭锰矿矿区废弃地的栾树、杜英混交林生态系统的地表水、土壤、林木及死地被物的养分含量进行对比研究.结果表明:冰冻灾害后,林地地表水的pH值、电导率、溶解氧、K、Ca、Mg含量明显减少,Zn、Mn、Pb含量显著增加;林内土壤含水量、全P、全K含量显著增加,速效N、速效P、速效K含量明显减少,微量元素Cu、Pb、Co含量增加,Fe、Zn、Mn、Cd、Ni含量减少;林木枝、叶、干中含水量均显著减少,树干中N、P、Ca、Mg、Cu、Zn、Mn、Cd、Ni、Pb、Co含量增加,树枝和树叶中P、K、Mg减少,而Cu、Fe、Zn、Mn、Cd、Ni、Pb、Co含量却增加;林地上的死地被物中K、Mg在各组分(未分解、半分解、已分解)含量降低,Cu、Fe、Mn、Ni、Co含量增加.可为突发性自然干扰对植物生命活动的影响及抗御机理的研究提供基础数据. 相似文献
18.
Variation in the chemical composition of green leaves and leaf litters from three deciduous tree species growing on different soil types 总被引:2,自引:0,他引:2
The chemical composition of green leaves and leaf litters of sweet chestnut (Castanea sativa), oak (Quercus robur) and beech (Fagus sylvatica) were determined for 26 sites grouped into high fertility (HF) and low fertility (LF) soils according to base saturation and N-mineralization potentials. Measurements were made of total carbon, acid detergent fibre (ADF), Klason lignin, holo-cellulose, sugar constituents of hemicellulose and phenylpropanoid derivatives of lignin, and nutrient concentrations (N, Ca, P, Mg, K and Mn). Leaf and litter constituents varied within and between species according to soil groups, but beech showed contrasting responses to oak and chestnut. Beech leaves had lower ADF, lignin and cellulose on HF soils than LF soils, whereas oak and chestnut leaves had higher ADF, lignin and cellulose on HF than the LF soils. Conversely, the same constituents in beech leaf litter were higher on HF soils than LF soils, but lower in oak and chestnut leaf litter on HF soils than LF soils. The phenylpropanoid derivatives of lignin and sugar constituents of hemicellulose also showed similar variations in relation to soil groups with contrasting patterns for in leaves and litters. Re-absorption of N from leaves before litter fall was negatively correlated with soil N mineralization potential for beech (highest on LF soils) but showed an unexpected, positive relationship for oak and chestnut (highest on HF soils). These intra-specific differences of leaf and litter chemistry in relation to soil fertility status are unprecedented and largely unexplained. The observed patterns reflect phenotypic responses to soil type that result in continuum of litter quality, within and between tree species, that have been shown in related studies to significantly influence litter decomposition rates. 相似文献
19.
Léa Bedel Arnaud Legout Anne Poszwa Gregory van der Heijden Mélanie Court Noémie Goutal-Pousse Emmanuelle Montarges-Pelletier Jacques Ranger 《Annals of Forest Science》2018,75(4):103
Key message
Aggregation was studied in two acidic forest soils (NE France) to investigate the potential link between available Ca and Mg content and soil aggregate size distribution and properties. Clay content influenced the aggregation status while clay mineralogy influenced aggregate stability and dynamics. Aggregation status and reactivity of soil components contributed to the difference of exchangeable Ca and Mg content in topsoil between the two sites.Context
Though nutrient fluxes are important to define forest soil chemical fertility, the quantification of nutrient reservoirs in the soils and their availability to tree uptake is essential. A thorough understanding of nutrient availability requires an investigation of nutrient location and distribution in the soil solid phase.Aims
The general aim was to investigate the potential link between available Ca and Mg content and soil aggregate size distribution and their properties (chemical, physical, mineralogical).Methods
Soil aggregates were separated according to three size classes (200–2000 μm; 50–200 μm; <?50 μm) in two forest soils of the Lorraine plateau (France), both classified as Luvisols ruptic. The physical, chemical, and mineralogical properties were measured for each aggregate class.Results
We showed that the relative abundance of an intermediate aggregate class [200–50 μm] was relevant to explain the difference of exchangeable Ca and Mg between sites. These aggregates were the poorest in organic and reactive mineral components and were unstable, which may mitigate the retention of Ca and Mg by ion-exchange.Conclusion
This study highlights the role of aggregation and reactivity of soil components as relevant determinants of cation availability to tree uptake in soils.20.
Maurício Bergamini Scheer 《Journal of Forest Research》2011,16(1):76-81
The ecosystems occurring on dystrophic soils, such as sandy soils, are highly dependent on nutrients from the atmosphere and
those cycled by their own biota. Nutrient inputs from rainfall and throughfall were measured between October 2001 and August
2003 in a secondary Atlantic rainforest in southern Brazil. Canopy interception (rainfall minus throughfall) was 17.3% of
the annual rainfall of 2,235 mm. Monthly interception ranged from 12 to 31% during the rainiest months (precipitation above
200 mm) and from 1 to 45% during the driest months (precipitation below 50 mm) indicating relatively high variability during
this period. The studied site may be susceptible to water stress in this period due to the high permeability of the sandy
soil. Approximately 80% of the Ca and Na and 57% of Mg were mainly from rainfall (bulk deposition) whereas the main input
source for K was net throughfall (about 78%). Mean annual inputs via throughfall (in kg ha−1) were: 90.6 for Na, 29.1 for K, 7.1 for Ca, and 2.9 for Mg. The highest nutrient inputs occurred during the rainy season.
Na fluxes were relatively high, while K, Ca, and Mg inputs were low, compared with other tropical and subtropical forests.
Information on nutrient fluxes for different forest ecosystems are fundamental for building up a database that can give support
to environmental diagnosis, to forest management, and to conservation and restoration techniques. 相似文献