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2
100%
Sylwan
|
2005
|
tom 149
|
nr 09
51-58
Research on the effect of birch regeneration on changes occurring in the environment on former farmlands included a quantitative and qualitative analysis of the biomass growing on the research plots. Five experimental plots were selected in the Mazovia region: two in Dobieszyn and the Kampinos National Park and one in Kozienice. The analysis performed on each plot was concerned with the amount and chemical composition of biomass in four patches of vegetation, characterised by the different ages of the birch trees growing there. The vegetation patches were classified according to age group, i.e. I: 1–4 years old, II: 5–8 years old, III: 9–12 years old and IV: over 12 years old. Biomass samples were collected in the field and determined in kg DM/ha using the following components: roots, stem, bark,branches, assimilation apparatus, litterfall and the total biomass of the other (except birch) plants. For all the above-mentioned groups, the content of the elements N, C, S, Ca, K, Mg, Na, P, Mn, Cu, Fe, Zn, Pb, and Cd was determined. This allowed us to obtain both the values of the concentrations of particular substancesand their allocation in both the organic matter and litterfall. The aim of theresearch was to discover whether the allocation of elements changes with the age of birch growing on former farmland.
The aim of the study was to apply the forest soil trophic index (ITGL) in the assessment of post−agricultural soil under naturally regenerated silver birch (Betula pendula Roth.) stands. The study was conducted in Mazowieckie region (central Poland) in 10 locations (tab. 1). In each location we established 4 study plots with naturally regenerated silver birch of different age. The age of the investigated stands ranged from 2 to 17 years. On each study plot samples from three upper soil horizons (0−5 cm, 5−15 cm and 15−50 cm) were collected for laboratory analysis. The following characteristics were determined in the soil samples: pH, organic carbon (C) and total nitrogen (N) content, particle size and the content of exchangeable base cations (Ca, Mg, Na and K). These soil characteristics were on used for ITGL calculation. Chemical properties of soils under silver birch regeneration varied with regard to trees age, whereas physical attributes turned to be rather stabile over the time (tab. 2). According to ITGL value investigated soils were classified as eutrophic. It is probably the effect of high base cations content, which is a result of systematic fertilization during the long term agricultural use. The insignificantly different ITGL values for the studied soils (tab. 3) indicated their similarity in terms of site productivity potential and soil−geological characteristics. The soil properties, especially the quality of soil organic matter described with C/N ratio, improved several years after the cessation of agricultural activity and spontaneous afforestation. The obtained results indicate that silver birch can be used in the stand composition on post−agricultural areas.
The paper analyses the production and allocation of biomass in young, spontaneoussilver birch afforestation occurring on post-agricultural lands in the Mazowszeregion (central Poland). We investigated 114 sample plots of age varying from 1 to 19 years. During the first 15 years after their establishment on abandoned farmland, the naturally regenerated silver birch stands produced on average approximately 75 tons of dry biomass per hectare. The major (50–70%) part of this biomass was stored in the tree stems and this share increased with age. The fractions of biomass in the foliage and roots decreased over time, while the share of biomass in the branches remained rather constant. The significant age-dependency of the allometric relationships suggested the need to use age-sensitive biomass expansion factors to estimate the biomass from the stem volume.
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