Effect of Mg fertilization on yellowing disease of Norway spruce at higher elevations of the Šumava Mts., Czech Republic

Abstract

Norway spruce yellowing and defoliation caused by Mg deficiency was frequently recorded on many sites of the Šumava Mts. (Bohemian Forest Mts.) since 1980's. A forest experiment aimed at investigation response of spruce to Mg application (commercial fertilizer SILVAMIX® Mg NPK) was set up in 1998. Fertilizer was applied manually in a dose of 96.5 kg Mg/ha in spruce (S) and beech-spruce (BS) vegetation altitudinal zones in spring 2000. Immediate decrease of yellowing was revealed in fertilized plots in both vegetation zones and yellowing almost completely disappeared at the end of the investigation in 2005. Further, fertilization resulted in stabile foliation while marked defoliation was reported from control plots in both vegetation zones. Mg deficiency can be effectively eliminated by appropriate fertilizer application. Balanced nutrition contributes to long-term vigour and stability of forest stands.