Nutrition of radiata pine established on an infertile siliceous sand in South-west Victoria.  P. W. Geary, P. Hopmans and D. W. Flinn.  August 1984.  11 pp. (unpubl.)

SUMMARY

Young sand is an infertile siliceous sand previously considered incapable of supporting productive plantations of Pinus radiata D. Don (radiata pine). Availability of soil phosphate was suspected as being the major limiting factor for growth. During 1971 a field trial was established at Rennick, in South-western Victoria, to compare four sources of phosphate for P. radiata establishment on this soil type.

Growth response to fertilisation at planting was negligible. Foliar analyses showed that all trees, including those unfertilised, had 'satisfactory' phosphorus and nitrogen concentrations for the first two years after planting. By age six years though, phosphorus concentrations had declined to 'low' levels, corresponding with the onset of deficiency symptoms. Nitrogen concentrations also declined during this period to 'marginal' levels, whereas levels of potassium, calcium, magnesium, iron and manganese remained adequate for satisfactory growth. Symptoms of zinc deficiency were alleviated by a foliar application of zinc sulphate four years after planting. The evidence suggested that the trees initially may have benefited from a flux of nutrients, particularly nitrogen and phosphorus, through mineralisation of organic matter following clearing of native forest and site preparation and that, thereafter, the inherent infertility of the soil became apparent as biomass and nutrient demand increased. Soil analyses showing the extreme paucity of soil phosphate (150 kg ha^-1 total phosphorus in surface 100 cm) and published data showing the quantities accumulated by P. radiata over a rotation, clearly indicate that soil phosphate reserves need to be supplemented sometime during the rotation, through fertilisation, if plantations on this soil are to be productive.

The results suggest that Young sand can support productive plantations of P. radiata, provided nutrient deficiencies are avoided through the appropriate use of fertilisers. A broadcast application of phosphate fertiliser and a foliar application of zinc sulphate at about 3-4 years of age appear to be essential. An application of nitrogenous fertiliser might also be required.

Also published:

Geary, P.W., Hopmans, P. and Flinn, D.W. (1985)  Nutrition of radiata pine established on an infertile siliceous sand in South-western Victoria.  Dep. Conserv., For. and Lands, State For. and Lands Serv., For. Tech. Pap. 30: 26-34.