Response of radiata pine in the Neerim East Plantation to fertilisers containing N and P applied at planting.  D. W. Flinn, P. Hopmans, I. Moller and K. Tregonning.  April 1979.  11 pp. (unpubl.)

SUMMARY

A field experiment is described which evaluates the early growth response of Pinus radiata to four levels of N (as ammonium sulphate at 0, 34, 68 and 136 g/tree) and P (as superphosphate at 0, 113, 226 and 452 g/tree) applied at planting. The experiment was undertaken at four sites which covered a wide range of native vegetation types in the Neerim East plantation extension area.

N, P, site and the P x site interaction significantly affected early growth. All sites were recolonised by a wide range of native species which had an above-ground biomass of 3720 to 6570 kg/ha depending on the site and contained only 1.3 to 2.6 kg/ha P three years after the sites were planted. Growth responses of pine to P was marked at two sites and moderate at the others. Each site was considered to be P deficient on the basis of soil tests and the occurrence of deficiency symptoms and low foliar levels in unfertilised trees, but variable P response between sites was attributed to differential competition for soil moisture rather than available soil P by recolonising species.

The work showed that effective site preparation followed by the application of P soon after planting is essential for satisfactory establishment of P. radiata on sites similar to those investigated, and confirmed that NP fertilisers should not be applied in the presence of weed competition.

Also published:

Flinn, D.W., Hopmans, P., Moller, I. and Tregonning, K. (1979)  Response of radiata pine to fertilisers containing N and P applied at planting.  Aust. For. 42 (2): 125-31.