%0 Research Notes
%T The effect of repeated fertilizations on volume growth and needle nutrient concentrations of Scots pine (Pinus sylvestris L.) on a drained pine mire
%A Rautjärvi, Heli
%A Kaunisto, Seppo
%A Tolonen, Timo
%D 2004
%J Suo - Mires and peat
%V 55
%N 2
%U http://suo.fi/article/9833
%X The nutritional status of Scots pine (Pinus sylvestris L.) stands growing on a nitrogen-rich,
drained pine mire in western Finland was studied after refertilization using needle
analysis and the response of stand volume growth. The main aim was to find out if K-refertilization
alone could maintain or increase the volume growth without causing a
nutrient imbalance between K and P. The initial fertilization was carried out in 1961 -
62 using PK fertilizer and refertilized in 1976 and 1989 with different combinations of
nitrogen (N), phosphorus (P), potassium (K) and boron (B). Needle samples were taken
and the tree stands were measured in 1996 and 2001. Peat samples were taken in 2002.
According to the needle analysis results, the concentration of P was above the deficiency
level in all the treatments in 1995 and 2000. There was a clear shortage of K in
the needles collected from the control treatment, but the concentration of K was still
adequate 12 years after the latest K refertilization. The volume growth of the stands
clearly responded to the 1976 refertilization with K alone, which was probably due to
the fact that trees had been suffering from K deficiency before the first refertilization
and 14-15 years thereafter. After the second refertilization, the combination of K and P
increased the annual volume growth more than refertilization with K alone. This indicates
that about 25 years after the initial fertilization, there was already some shortage
of P. The highest stand volume was associated with the combined K (1976) and PK
(1989) refertilization treatment. Refertilization with N did not increase stand volumes
during the study period.