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1.
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   

2.
The purpose of this research was to study the influence of the vegetation on the soil C pool of forests of pines (Pinus sylvestris) and oaks (Quercus pyrenaica), located in Central-Western Spain. Horizons from selected soils located in these forests were sampled, and the soil organic C (SOC) was determined. In addition, in vitro incubation experiments were carried out, under controlled conditions, to monitor the stability of SOC against the microbial activity. Soil humus fractions were isolated following a classical procedure of chemical fractionation using alkaline solutions, before and after the incubation experiment. A deeper O horizon was found under the pine forest than under oak one; however, higher SOC content was found in the oak site than that under pine one. During the in vitro mineralization process, a lower CO2 production by the soil sample from pine forest was observed, in relation to that emitted by the oak soil. In addition, a lower humification degree was estimated for the soil humus under pines than for that under oaks. In conclusion, replacement of oaks by pines produced a decrease in SOC accumulation and a lower quality of humus in the forest soils.  相似文献   

3.
The Humus Index, based on the visual assessment of topsoil horizons and a classification of humus forms, is a numerical score which can be used as a correlate of stand and soil properties. In oak stands from the Montargis forest (Loiret, France) we observed a good linear relationship of the Humus Index with most parameters describing stand development (age, basal area (BA), height and diameter at breast height of dominants) and soil type (depth of clay horizon). The relationship with parameters describing nutrient availability (exchangeable bases, base saturation) was similarly good but nonlinear. In the studied forest the Humus Index was affected first by stand age and second by soil type. When corrected for age and soil type, data (96 pooled estimates) indicated a slight decrease in the Humus Index (shift towards more active humus forms) in stands converted from old coppices-with-standards when compared with even-aged high forest.  相似文献   

4.
In this study soil samples were taken from the O/A and B horizons of undisturbed forest, active pasture, and 8- to 12-year-old teak and mixed native plantations. Samples were analyzed for K, Ca, Mg, soil organic carbon, pH, exchangeable acidity, bulk density, and compared with a fertility equation. Bulk density was significantly lower in the undisturbed forest than other land uses, suggesting that after approximately 10 years of growth neither plantation lowered bulk density significantly from that of the active pasture. Teak plantations had significantly higher Mg and K (B horizon) and Ca (O/A horizon) concentrations than the undisturbed forest. This trend suggests that exchangeable base concentrations increase when land use changes from undisturbed forest to pasture, then pasture to plantation, with the most pronounced effect of this in teak plantations exhibiting more high fertility plots than other land uses. Soil organic carbon concentration was similar for all land uses except for a significantly lower concentration in teak plantations than in active pasture (O/A horizons). These results suggest that teak plantations may be advantageous for increasing soil fertility but, with respect to restoration of undisturbed forest conditions, present significant deviations in soil chemistry. Options for improved plantations soil management are discussed.  相似文献   

5.
It was hypothesized that increasing air and/or soil temperature would increase rates of microbial processes including litter decomposition and net N mineralization, resulting in greater sequestration of carbon and nitrogen in humus, and consequently development in OH horizon (humus horizon). To quantify the effect of temperature on biochemical processes controlling the rate of OH layer development three adjacent forest floors under beech, Norway spruce and mixed species stands were investigated at Soiling forest, Germany by an incubation experiment of OH layer for three months. Comparing the fitted curves for temperature sensitivity of OH layers in relation to net N mineralization revealed positive correlation across all sites. For the whole data set of all stands, a Q10 (temperature sensitivity index) value of 2.35-2.44 dependent on the measured units was found to be adequate for describing the temperature dependency of net N mineralization at experimental site. Species-specific differences of substrate quality did not result in changes in biochemical properties of OH horizon of the forest floors. Temperature elevation increased net N mineralization without significant changes in microbial status in the range of I to 15℃. A low Cmic /Corg (microbial carbon/organic carbon) ratio at 20℃ indicated that the resource availability for decomposers has been restricted as reflected in significant decrease of microbial biomass.  相似文献   

6.
Denitrifying enzyme activity (DEA) is defined as N2O production rate over the first eight hours of anaerobic incubation of soil slurries at 15°C with added nitrate and acetylene. Organic fraction explained 81 % of the spatial variation in DEA among soil horizons of beech (Fagus), alder (Alnus), and spruce (Picea) forests, and spruce ciearcuts. Nitrate and pH limit denitrification in anaerobic O horizons at 15°C. Thick, poorly drained O horizons, such as in alder forest, have a high capability for denitrification. Failure to recover all added nitrate in O horizon incubations suggested both production of unmeasured NO and dissimilatory reduction of nitrate to ammonium. In mineral horizons, N2O production was small and could not be increased by increasing nitrate, carbon, pH, and phosphorus; some other factor appears to prevent significant denitrifier activity in acid forest mineral horizons.  相似文献   

7.
The main island of Okinawa, in southwestern Japan, is characterized by a subtropical climate, coral reefs, and reddish soils, which contain Acrisols and Cambisols (FAO/UNESCO classifications). Recently, due to soil erosion on hilly lands, the coral reefs have been damaged by an inflow of reddish soil. Forest clearing is thought to one of the factors increasing rain splash erosion rates on hilly lands, because it is believed that clearing disturbs the forest floor and causes the supply of litter to stop. After clearing, A0, A and B horizons will be denuded, one after the other, by rain splash. In this study, we measured rain splash erosion rates of undisturbed samples of A0, A and B horizons using an artificial rainfall apparatus. The results of experiments on rain splash erosion clarified several aspects of the erosion process in a clearing site. First, it was found that the rain splash erosion rates were higher in fresh litter than in decomposed litter, in decomposed litter than in the A horizon, and in the A horizon than in the B horizon. Thus, the erosion rate increases with soil depth. Secondly, surface-gleyed red and yellow soils are mostly vulnerable to rain splash erosion. The erosion rates of these soils are two to three times higher than those of the red soil and the yellow soils. Thirdly, the erosion rates are affected mainly by bulk density and saturated hydraulic conductivity, not by clay ratio and dispersion ratio. Lastly, the difference between erosion rates of surface-gleyed red and yellow soils and other soils will be even greater if a soil crust has formed, because the formation of a soil crust increases the rain splash erosion rate.  相似文献   

8.
The objectives of the study were to investigate mineral soil profiles as a living space for microbial decomposers and the relation of microbial properties to soil acidity. We estimated microbial biomass C on concentration (g g–1 DW) as well as on volume basis (g m–2) and the microbial biomass C to soil organic C ratio along a vertical gradient from L horizon to 20 cm in the mineral soil and along a gradient of increasing acidity at five beech forest stands in Germany. Microbial biomass C concentration ranged from 17,000–34,000 g Cmic g–1 DW in the litter layer and decreased dramatically down the profile to 29–264 g Cmic g–1 DW at 15–20 cm depth in the mineral soil. This represents depth gradients of microbial biomass C concentrations ranging from a factor of 65 in slightly acidic and up to 875 in acidic soils. In contrast, microbial biomass C calculated on a volume basis (g Cmic m–2) showed a different pattern since a considerable part of the microbial biomass C was located in the mineral soils. In the soil profile 22–34% of the microbial biomass C was found in the mineral soil at strictly acidic sites and as much as 64–88% in slightly acidic soils. The microbial biomass C to soil organic carbon ratios decreased in general down from the L horizon in the forest floor to 0–5 cm depth in the mineral soils. In strongly acidic mineral soils however, the C to soil organic carbon ratio increased with depth, suggesting a positive relation to increasing pH. We conclude from depth gradients of soil pH and microbial biomass C to soil organic carbon ratio that pH affects this ratio at acidic sites. The inter-site comparison indicates that acidity restricts microbial biomass C in the mineral soils.  相似文献   

9.
THE OCCURRENCE OF PODZOLS UNDER DECIDUOUS WOODLAND IN THE NEW FOREST   总被引:1,自引:0,他引:1  
DIMBLEBY  G. W.; GILL  J. M. 《Forestry》1955,28(2):95-106
Examination of the soils of six small unenclosed oakwoods, allon the Plateau Gravels of the New Forest, showed that two ofthem were essentially brown forest soils, but the other fourhad pronounced features of podzolization. Pollen analysis revealedthat the four podzolized ones had once borne heathland, whereasthe other two had no such history. Particular attention waspaid to the state of the humus layer in each wood. Those withbrown forest soils maintained mull humus, probably by virtueof their mixed floristic composition. For those woods whichhad developed from heath it was demonstrated that holly wasa pioneer species which, through its litter, could convert rawhumus to mull humus, so that these woods showed mull conditionsat the surface of what otherwise appeared to be a heath podzol.In both types of wood beech had become established avificially,and under old trees raw humus formation with attendant podzolizationwas demonstrated. It is suggested that the natural climax onthese poor gravels is still an oak-dominated forest in equilibriumwith a brown forest soil. Podzolization is a secondary condition.  相似文献   

10.
BROWN  A. H. F.; ILES  M. A. 《Forestry》1991,64(2):169-187
A study was made of the changes and variation in the chemistryof rainwater passing through the different strata of separateecosystems of four tree species (oak, alder, spruce and pine)on the same site at Gisburn (Bowland Forest), north-west England.Waters were sampled as rain, throughfall, forest-floor leachateand soil waters from both the A and B/C horizons; and analysedfor NH4-N, NO3-N, PO4-P, K, Ca, Mg, Na, Al, SO4-S, Cl, totalorganic carbon and pH. Species differences — often markedones — appear to exist in the concentrations of most solutesin most strata. The between-species differences in throughfallchemistry provide little guide to the chemistry of waters lowerdown the profile: the forest floor is a particularly importantsource of further species differences, e.g. variation in NO3production and the resulting effects on acidity and other ions. The chemistry of the soil waters provides some indication ofpossible drainage losses, although the question of which horizonacts as the source of drainage waters on this site remains unanswered.The levels of H and Al, in particular, are very different betweenthe upper mineral soil (A horizon) and the lower B/C horizon.In general, and based on these concentration data only, oakis associated with smallest potential solute losses, pine thegreatest. Received 13 February 1990.  相似文献   

11.
Carbon and nitrogen stocks and their medium-term and readily decomposable fractions in topsoils were compared in relation to soil microbial biomass and activity along sequences from coniferous to deciduous stands. The study was carried out in the Ore Mountains and the Saxonian lowland, representing two typical natural regions in Saxony, Germany. In accordance with current forest conversion practices, the investigation sites represent different stands: mature conifer stands of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) (type A); Norway Scots spruce and pine with advanced plantings of European beech (Fagus sylvatica L.) or European beech/Common oak (Quercus petreae Liebl.) (type B); and mature deciduous stands of European beech and European beech/Common oak (type C). The investigated forest sites can be grouped into three silvicultural situations according to the development from coniferous stands to advanced plantings and finally mature deciduous forests (chronosequence A–B–C). The organic layer (L, F and H horizons) and uppermost mineral soil (0–10 cm) were analysed for potential C mineralisation, microbial biomass, concentrations of total C and N (TOC and TN) and for medium-term and readily decomposable C and N fractions, obtained by hot- and cold-water extraction respectively. The results showed an increase in organic layer thickness and mass as well as TOC and TN stocks along the forest sequences in the lowland. Yet, underplanted sites with two storeys revealed higher organic layer mass as well as TOC and TN stocks as compared to coniferous and deciduous stands. Stocks of hot- and cold-water-extractable C and N in relation to microbial biomass and its activity revealed a high turnover activity in deeper organic horizons of deciduous forests compared to coniferous stands. The stand-specific differentiation is discussed in relation to microbial biomass, litter quantity and quality and forest structure, but also with respect to the site-specific climatic factors and water budget as well as liming and fly-ash impacts. Results indicate higher dynamics in deciduous stands in the lowland especially during the initial turnover phase. The elevated microbial activity in deeper organic horizons of deciduous litter-influenced sites in spring is discussed as a specific indicator for long-term C sequestration potential as besides C mineralisation organic compounds are humified and thus, can be stored in the organic layer or in deeper soil horizons. Due to liming activities, stand-specific effects on organic matter turnover dynamics have evened out today in the Ore mountain region, but will presumably occur again once base saturation decreases. Here, the stand-specific effect on microbial biomass can currently be seen again as Cmic in the L horizon increased from spruce to beech. Our study sites in the lowland revealed no significant fly-ash impact. Differences between sites were evaluated by calculating the discriminance function. TOC and TN as well as medium-term degradable C and N were defined in this study as indicators for turnover dynamics along forest conversion sites.  相似文献   

12.
Effects of forest management and soil acidity on herb layer vegetation were studied after 10 years on 190 permanent plots in south Swedish beech (Fagus sylvatica) and oak (Quercus robur) forests. Species richness generally increased with management intensity, mainly due to establishment of ruderal species from the seed bank. Species richness of the typical forest flora was unaffected by management. Moderate management of oak stands favoured several species which are commonly found in semi-natural pastures. Classification and ordination of the data showed that the main floristic gradient within Swedish beech and oak forest vegetation is related to soil acidity. Species richness of the typical forest flora was strongly positively correlated with soil pH in beech forests, but this correlation was weaker in oak forests. The number of herbaceous plants with a broader habitat range increased with pH only in the oak forest plots. Long term changes in the forest environment, which may affect the vegetation, are the decline of grazing 150-50 years ago and soil acidification mainly caused by atmospheric pollutants during the last 50 years. In the one-decade perspective of this study, however, we did not find a general trend towards a more acid-tolerant flora. Neither could we find a general decrease of pasture species in currently ungrazed oak stands. The results indicate that most typical forest plants are well adapted to and partly depend on occurrence of canopy gaps and soil disturbance. If canopy thinning is followed by periods of canopy closure the characteristic shade tolerant flora of Swedish beech and oak forests may be able to persist as long as soil chemical limits of existence are not exceeded.  相似文献   

13.
Soil variability was assessed in a 74.2-ha area within the Žofínsky prales natural forest. Parameters evaluated for 1765 soil profiles inside 353 graticule plots were as follows: (1) thickness of organic horizons, (2) thickness and form of mineral horizons, (3) humus form (HF), (4) soil taxonomic unit (STU) and (5) anomalies. In addition, soil reaction (pHKCl) and oxidizable carbon content (Cox) were measured in the laboratory for 734 samples from the upper mineral (A) and lower mineral (B) horizons. The most frequently occurring humus form was mor followed by moder, hydromor and peaty T-horizon. Entic Podzols, Dystric Cambisols, Haplic Cambisols, Albic Podzols, Histic (or Haplic) Gleysols, Endogleyic Stagnosols, Fibric or Hemic or Sapric Histosols and Stagnic Gleysols were all present at the site despite its homogeneous geological bedrock. Overall coefficient of variance (CV) was lower in terrestrial soils compared with (semi-)hydromorphic soils. Overall variance decreased in both soil groups with increasing depth, as did CV differences between the fine (up to 10 m) and the locality scales. The lowest CV values occurred for Cox and pHKCl. The CV values differed between STUs as well. Compared to lower horizons, variograms of upper horizons showed greater autocorrelation at the intermediate spatial scale (10–320 m)—ranging from 50 to 150 m. Semivariance values, however, reached 70–80% of sill already at a distance of 10 m. The most significant factor of variability at all studied spatial scales is presumably the soil disturbance regime, followed by terrain micro-topography and the effect of tree species.  相似文献   

14.
Reinvestigation of 90 soil profiles sampled for pH measurements in 1927 revealed a general decrease in pH with 0.3–0.9 units (measured electrometrically on field‐moist samples in water with the same ratio soil/water on both occasions). All soil horizons (A0, A2, B and the subsoil, C, at 70 cm depth) had become more acid beneath all types of canopy (beech, oak, spruce planted during different periods), but the spruce stands were on average more acid than the hardwoods. In the upper soil horizons (A0 and A2), old spruce stands were more acid than the young ones at both samplings, but this effect was small in the B horizon and absent in the C horizon. While the tree species effect and age effect in the spruce stands may be called biological acidification, the acidification of deeper horizons, now often below pH 4.5 and in the aluminium buffer range, seems difficult to explain without assuming an influence of acid deposition.  相似文献   

15.
Calcareous amendment and/or fertilization trials were carried out in a declining 66-year-old Norway spruce (Picea abies (L.) Karst.) stand in the Vosges mountains (northeast France, altitude 1100 m) in 1985. The aim was to test tree response to nutritional deficiencies (Ca + Mg) and to alleviate soil acidity. In 1988, experimental equipment was set up to collect atmospheric input (bulk precipitation, throughfall) and soil seepage water. The soils are podzolic (‘ocre-podzolique’), derived from an acid-poor granitic bedrock (‘granite du Valtin’). The soils are coarsely textured, hence very porous. They are very acid (pH 3.4 in the A1 horizon, and pH 4.1 in the Bs horizon). The cation exchange capacity (CEC) is highly saturated in exchangeable acidity: 86% in the A1 horizon. Ca2+ + Mg2+ saturation is very low (<10% in A1 and <1% in the subsoil). Liming and fertilization significantly increase soil pH, base cation saturation and decrease soil acidity, especially in the surface horizons.

Bulk precipitation is dilute and acidic (pH 4.5); ion concentration of the precipitation greatly increases after passing through the tree canopy. Dry deposition is moderate and has values in the lower range reported for Europe.

Nitrification produced large amounts of NO3-N and H+ ions in the O layer and organo-mineral horizons. Nitrate and aluminium dominate the chemical composition of the soil see-page water.

Liming induces a considerable rise in the soil solution pH and the base cations (Ca2+ + Mg2+) and decreases nitrate and aluminium substantially. Liming alone seems to lower the rate of nitrification. Addition of fertilizers increases the deep drainage of base cations which could reduce the long term efficiency of liming.

Improvement of tree health-status accords with the positive effects of liming and/or fertilization on the soil's solid phase and solution.  相似文献   


16.
This paper is focused on the soil characterisation of forest sites where Castanea sativa wood stands are located in Catalonia (NE of Spain) as a former and essential requirement to future afforestation programs with this species. From 28 sample plots field survey, several soil indexes have been calculated and, their central and marginal values have been established, defining a range of soil conditions where this species can successfully live in Catalonia. So, we can see that soils are developed on acid bedrock as parent material, basically igneous rocks such as granodiorite and granite, but they occur on schist as well. Their predominant texture is loamy-sand. Soils have low water holding capacity, mainly due to their high stoniness and steep slopes. Nevertheless, regular rainfall distribution all year around, avoids meteorological drought as well as reduces physiological drought. Annual rainfall distribution and steep slopes are responsible for the dwarf development of argic horizons. Soils are relatively poor in organic matter, and despite being generally very acid they have forest mull humus forms.  相似文献   

17.
由于土壤性质和腐殖质含量的不同,土壤的含水量并不能很好地说明是否适宜植物的生长。本研究以土壤PF(表示土壤的水分状态,与植物的生长发育有密切关系的数值)为主要研究依据,将土壤含水率和PF联系起来,定量研究了贡嘎山地区亚高山暗针叶林不同演替阶段土壤的含水率与PF值之间的相互作用关系。研究结果表明:①在相同的PF时,随着暗针叶林演替的进展,土壤腐殖质层的含水率逐渐增加,即过熟林>成熟林>中龄林>幼龄林。②随着土层深度的增加,土壤容重增加,含水率减小,但各植被演替阶段之间土壤含水率差异并不显著。③植被不同演替系列主要是通过提高其土壤有机质含量,改善土壤结构,降低土壤容重和增加土壤毛管孔隙度等土壤物理特性,改善土壤的蓄水和持水性能。④本区暗针叶林土壤腐殖质层涵养水源作用最为明显。图1表2参15。  相似文献   

18.
Soil hydrological properties like infiltration capacity and hydraulic conductivity have important consequences for hydrological properties of soils in river catchments and for flood risk prevention. They are dynamic properties due to varying land use management practices. The objective of this study was to characterize the variation of infiltration capacity, hydraulic conductivity and soil organoprofile development on forest sites with comparable geological substrate, soil type and climatic conditions, but different stand ages and tree species in terms of the effects of forest transformation upon soil hydrological properties. The Kahlenberg forest area (50 km northeast of Berlin in the German northeastern lowlands) under investigation contains stands of Scots pine (Pinus sylvestris) and European beech (Fagus sylvatica) of different age structures forming a transformation chronosequence from pure Scots pine stands towards pure European beech stands. The water infiltration capacity and hydraulic conductivity (K) of the investigated sandy-textured soils are low and very few macropores exist. Additionally these pores are marked by poor connectivity and therefore do not have any significant effect on water infiltration rate. Moreover, water infiltration in these soils is impeded by their hydrophobic properties. Along the experimental chronosequence of forest transformation, the thickness of the forest floor layer decreases due to enhanced decomposition and humification intensities. By contrast, the thickness of the humous topsoil increases. Presumably, changes in soil organic matter storage and quality caused by the management practice of forest transformation affect the persistence and degree of water repellency in the soil, which in turn influences the hydraulic properties of the experimental soils. The results indicate clearly that soils play a crucial role for water retention and therefore, in overland flow prevention. There is a need to have more awareness on the intimate link between the land use and soil properties and their possible effects on flooding.  相似文献   

19.
Repeated analyses of exchangeable K, Ca, Mg and Zn revealed that the pools have decreased significantly in the topsoil (0–5 cm) of south Swedish beech forest during the 1980s. The largest decreases of K, Ca and Mg were found in the originally least acid soils, indicating that the limit for further losses from the topsoil is being approached in the most acid soils at today's deposition climate. The decrease of Zn was, on the other hand, largest in the most acid soils. Manganese had increased in especially the least acid soils, probably due to a conversion from non‐exchangeable pools as a result of the acidity change. The base saturation of the studied beech stands ranged 7.7–58.5% (mean 20.3%). The decrease rate of the exchangeable pools of K, Ca and Mg, estimated from two different time series has been relatively constant since 1949. The Zn pool has, however, decreased faster during the last decade, partly due to a lowered deposition of this element. Extrapolation of the data indicates that, as an average, only 20% of the pools of 1950 will remain in the topsoil in the year 2050.  相似文献   

20.
大兴安岭北部西坡寒棕壤标准剖面的研究   总被引:2,自引:0,他引:2  
张萍  屠星南 《林业科学》1996,32(4):325-333
在对大兴安岭北部林区寒棕壤进行多次面上调查及定位研究的基础上,根据初步拟定的“寒棕壤系统分类”,选择了具有广泛代表性的大兴安岭北部西坡潮查自然保护区作为寒棕壤标准剖面采集地点,并按“中国土壤系统分类研究项目”拟定的土壤剖面描述标准和土壤实验室分析项目及方法规范进行外业采集土壤标本和内业土壤分析。研究结果讨论了寒棕壤标准剖面的成土条件和基本性质;并以诊断层和诊断特性为基础研究检查了寒棕壤系统分类中的问题,对诊断层中的诊断表层(腐殖质表层、潜育特征),诊断表下层(风化B层、粘化层、灰化淀积层、灰化淀积特征)和诊断特性中的冻融特征、土壤水分状况、土壤温度状况、地表至50cm土层的石砾含量等进行了检查讨论。  相似文献   

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