Phosphate fertilisers for establishment of Pinus radiata on a soil with a high phosphorus sorption capacity.  D. W. Flinn, P. Hopmans and L. J. Bren.  August 1977.  8 pp. (unpubl.)

SUMMARY

This report deals with the study of phosphate fertilisers for establishment of Pinus radiata D. Don on the soil type Gorae gravelly loam at Heywood. This slightly acid soil has a high phosphorus sorption capacity. The fertilisers tested were granular superphosphate, ammonia reverted concentrated superphosphate, heated granular superphosphate and briquettes of dicalcium phosphate. Application rates were adjusted to supply 15.8 g of phosphorus to each tree at the time of planting.

Moderate growth response to all fertilisers accept briquettes of dicalcium phosphate were detectable four years after planting. Foliar phosphorus concentrations in two-year-old trees indicated poor uptake of applied phosphorus in all treatments. Foliar phosphorus concentrations declined to deficient levels in some treatments after four years, suggesting that the longevity of the growth response was likely to be very severely limited. Folia zinc levels were also undesirably low after four years, irrespective of fertiliser treatment.

It is evident that further studies are required to identify the optimum type, rate and placement of fertiliser for Pinus radiata establishment on soils with high phosphate retention capacities. It is possible that fertilisers containing both nitrogen and phosphorus could be the most effective.