A phosphate fertiliser study with P. radiata at Rennick on soils resembling Richmond Sand.  F.G. Craig, L.G. Bren and P. Hopmans.  February 1974.  11 pp. (unpubl.)

SUMMARY

1. This study has shown that radiata can be successfully established on soils resembling Richmond Sand at Rennick. Such dry infertile sands as these have been regarded as unsuitable for P. radiata plantations in the past.

2. A 1:1 mixture of lime and superphosphate was shown to be advantageous in achieving accelerated early growth on these soils. The magnitude of height growth responses achieved in the 3 blocks studied were 16%, 91%, and 47%, respectively, at an application rate of 227 gm per tree. Higher application rates were found not to be justified at this stage.

3. Mean mortality was high (25%) in one of the blocks; this being distinguished from the others by a small hill, and deeper surface soil above the “coffee-rock” layer characteristic of these soils. The reasons for this high mortality are not known, and it seems that these hilly sites, if extensive, should either be avoided at present, or planted at close espacement. The fertiliser was found to have no significant effect on mortality.

4. It is important to note that this study is still at an early stage, and on such soils it would be dangerous to regard the present results as any more than promising.