ZLV Online

Abstract

The biomass and vitality of fine roots was studied at twenty Norway spruce plots in the Czech Republic. At each plot roots were taken from twenty sampling points for two depth layers 0 – 10 cm and 10 – 20 cm. The vitality of forest stands (defoliation) and chemical properties of mineral soils were also used for the statistical evaluation. The mean fine root amount in the upper soil layer 0 – 10 cm varied from 78,6 to 455,7 kg.ha-1, in deeper mineral layer it was substantially lower. The root vitality was relatively high reaching more than 90% at half of studied plots. One of the plots with distinctively reduced root vitality (59%) was influenced by infestation of bark beetle. The root vitality exhibits only significant relation to the total nitrogen content in the deeper mineral soil layer (10 – 20 cm). The expected negative correlation with exchangeable aluminium was not found. The aluminium effect should be studied on the level of individual Al3+ species content or on the base cations/Al ratio in the soil solution. The found negative relation of root biomass and Ca or Mg content in the mineral soil was influenced by values from two monitoring sites with very high base saturation. After exclusion of these values as outliers, the significant positive correlation of root biomass and exchangeable magnesium was stated. Defoliation at monitoring sites correlated negatively with the active pH(H2O) in the 0 – 10 cm of mineral soil and total N in the deeper layer 10 – 20 cm. The found negative correlation of defoliation and total root amount should be considered carefully, because non-complete set of factors influencing the forest stand vitality was taken for the evaluation.