Fallstudie Hohe Matzen/ Duengung mit Magnesit und Mg-Hydroxid unterschiedlicher Loeslichkeit

1992

S. 142-151

19 Lit. Ang.

Unselbständiges Werk

200060494

The intention of the fertilizer experiment Hohe Matzen in Fichtelgebirge/NE- Bavaria is to increase the depth effect and the meliorative capacity of traditional lime fertilizers by readily soluble Mg-components. The experiment includes highly soluble Mg(OH)2 and less reactive magnesite. 15 experimental sites are located in 60 year old Norway spruce stands with heavy decline symptoms. Soils range from acid Brown Earth to spodosols. The sites are subject to needle yellowing due to Mg deficiency, high deposition loads (N and S), soil acidification and high mineralisation rates. Fertilization clearly increased Mg concentrations in the organic layer and in the mineral soil even to 70cm depth. pH-increase offertilized plots constantly exceeds the solution pH of control plots by 0.4 to l pH units. Accordingly NO3-values in the soil solution peaked. Nevertheless after 18 to 24 months nitrate concentrations declined below control plot values. Exchangeable Mg in the mineral soil was significantly increased. Due to its high reactivity improvement of chemical soil conditions (soil solution and nutrient status) by Mg(OH)2 was superior to MgO. Three years after fertilization a positive response of needle Mg content was observed. The experiment demonstrated, that fertilizer solubility influences temporal response and depth effects. Even at Hohe Matzen soil conditions were improved.