Keywords: forest fertilizers, Britain, deficiency symptoms, nutrient requirements, application.

In Great Britain the use of fertilizers has greatly increased the productivity of forest areas on nutrient-poor soils. Initially this was achieved by application of phosphate, but is now complemented by using nitrogen and potassium fertilizers on certain site types. The common sources are rock phosphate, urea and muriate of potash.

Fertilizer is normally applied in the first 20 years of the rotation, when growth responses are predictable. After this, nutrients are efficiently cycled and the crop becomes virtually independent of soil nutrient supply. The bulk of fertilizer usage is in Scotland and northern England where much of the afforestation program is on soils of low fertility. However, in the second rotation even these soils require less fertilizer due to the breakdown of harvesting residues.

To date no serious environmental effects have been associated with the use of forest fertilizers and conventional treatments are thought to have little effect on wood quality.

Charles M A Taylor BSc, MICFor., Forestry Commission Research Division, Northern Research Station, Roslin, Scotland.

23 Pages, 3 Figures, 76 Tables, 56 References.