SOIL MICROBIAL ACTIVITY IN THE COASTAL NORWAY SPRUCE [PICEA-ABIES (L.) KARST.] FORESTS OF THE GULF OF BOTHNIA IN RELATION TO HUMUS-LAYER QUALITY, MOISTURE AND SOIL TYPES
P. Merila et R. Ohtonen, SOIL MICROBIAL ACTIVITY IN THE COASTAL NORWAY SPRUCE [PICEA-ABIES (L.) KARST.] FORESTS OF THE GULF OF BOTHNIA IN RELATION TO HUMUS-LAYER QUALITY, MOISTURE AND SOIL TYPES, Biology and fertility of soils, 25(4), 1997, pp. 361-365
Relationships between chemical, physical and microbial properties in t
he humus layer, soil type and crown condition of Norway spruce (Picea
abies) were studied in stands located along the Finnish and Swedish co
asts of the Straits of the Gulf of Bothnia. Humus layers of ferric pod
zols had higher basal respiration (BASAL) than those of carbic podzols
and higher substrate-induced respiration (SIR) than those of both car
bic podzols and dystric gleysols. BASAL and SIR correlated with enviro
nmental factors associated with humus-layer fertility; i.e. they were
positively associated with pH and extractable K, Mn and P and negative
ly associated with organic-matter content of the humus layer. A short
lag-time was associated with humus-layer fertility and a long lag-time
with crown defoliation. Specific respiration increment was lowest at
sites with high field moisture and discoloured crowns. The results sug
gest that on carbic podzols and dystric gleysols poor nutrient status,
acidity and lack of oxygen due to excess moisture in the humus layer
result in low microbial activity and poor condition of spruce.