DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 7-8/1969 str. 31 <-- 31 --> PDF |
A CONTRIBUTION TO THE KNOWLEDGE OF THE CHANGES OF SOIL FERTILITY UNDER THE INFLUENCE OF FOREST TREE SPECIES Summary Investigated were changes of some soil fertility factors brought about by the influence of coniferous forest monocultures within a zone of Beech forests in the region of Western Croatia. The cultures are about 80 years old and occur in two localities, viz. Drvarija and Zagolik belonging to the area of perhumid climate according to the factor P/E = 128. The cultures of the first locality (Drvarija) grow on a brown soil with dolomitized limestone as parent rock within the zone of Fagetum croaticum seslerietosum Horv., and those of the second locality (Zagogik) on a brown acid soil with fine-grained Palaeozoic sandstones as parent material within the zone of Blechno-Fagetum Horv. forest plant community. Undex.equal ecological conditions was compared the state with each of the cultures of Norway Spruce, European Larch and Eastern White Pine with conditions of the soil in the natural Beech forest (locality of Drvarija). In the locality of Zagolik were performed comparisons with each of the cultures of Norway Spruce, Douglas Fir and Silver Fir Under natural Beech forest. Results of investigations are presented in Tabs. 1—8, and Figs. 1—4. The most imoprtant conclusions are as follows: 1. The greatest Ai-horizon depth and the greatest forest liter amount is exhibited by a brown acid soil under Douglas Fir and Norway Spruce. Brown soil on limestones has the mentioned values highest under Norway Spruce, and lowest under European Larch. 2. A Norway Spruce culture acidifies the soil, more on the limestone than on the sandstone. The decrease of the soil reaction amounts to 0.3—0.8 pH units. 3. In the brown soil on limestone were established larger amounts of total nitrogen and humus under natural forest vegetation than under cultures (plantings). In brown acid soil the condition is converse. 4. The process of accumulation of exchangeable bases within the adsorption complex of brown acid soil is most strongly pronounced unter the trees of Douglas Fir and Silver Fir. 5. The per cent content of N, P2O0, K2O, CaO and MgO in the forest litter and the amount of the latter are strongly affected by the tree species. Of the mentioned elements per ha. the forest litter of Douglas Fir contains 1735, Norway Spruce 868, Beech 428 and of Silver Fir 409 kg. (brown acid soil); while the forest litter of Norway Spruce contains 1860, Beech 1191, Eastern White Pine 587 and of European Larch 236 kg. of the mentioned elements (brown soil on the limestone). 6. According to the per cent content of the biogenic elements in the needle (leaf) litter there were evaluated as organisms-concentrators (within the zone of Fagetum croaticum seslerietosum Horv.) European Larch with regard to phosphorus and Beech with regard to calcium. The same properties with regard to nitrogen and phosphorus are displayed by Silver Fir within the zone of Blechno- Fagetum Horv. forest association. 7. No morphological signs were noticed to the effect that the soil erosion due to water would assume a more unfavourable patern in a terrain under forest culture (planting) than under natural forest vegetation (regeneration). 8. In a general way the analysed factors of soil fertility have experienced no untoward change. |