Adaptation of stands and tree species to changes in nutrial conditions under different moisture and nutrition regimes
2003
Pikk, J. (Estonian Agricultural University, Tartu (Estonia). Forest Research Institute)
Drainage and fertilisation have the greatest effect on stand growth. An analysis of forest inventory data obtained at a 25-year interval conifermed that on drained peatlands the area of alder fens, transitional bogs and alder-birch fens has considerably decreased while that of swamps and Filipendula sites has increased. The annual loss of peat on basis with better filtration exceeds up to 1.3 cm. Inadequately maintained drainage networks cause paludification. The influence of rising ground water levels on tree growth is the greatest in stands growing on swamps. After fertilisation, the time for the growth rate to return to normal in dry mineral soil areas is different than in potentially wet areas. To determine tree radial growth, about seventeen thousand timber samples were used. Stands on wet fine sandy soils with a relatively high ground water level showed better capability of withstanding greater amounts of nitrogen fertilisers. Stands growing on dry sandy soils with permeable subsoil are very sensitive to excessive amounts of nitrogen. The effect of PK, P and K fertilisers on middle-aged pine stands on the Vaccinium vitis-idaea site type is relatively small and the stands' radial growth increment returns to normal in 7-8 years
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
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