The Growth of Radiata Pine On Lateritic Soils at Second Valley,South Australia

Factors involved in the growth of P. radiata (D. Don) on soils of a lateritic landscape have been examined by soil and foliar analysis and the measurement of ring width; this has given an appraisal of factors influencing growth in the past and at the present time.

Perched water tables, which often occurred in winter on the plateau where there were lateritic podzolic soils, did not depress growth. The addition of phosphate was essential, with responses lasting for about 8 years with superphosphate. Regression relationships between the annual growth increment (ΔV in cubic feet) and foliar levels of nitrogen (N) and phosphorus (P) were found for three different foliar sampling positions; these relationships had the form:

ΔV = 4.5%P + 0.28%N—0.47.

Considerable variation was found in the foliar levels of nitrogen, phosphorus, copper, zinc, boron, nickel, molybdenum, chromium and ash for different sample positions within the tree. Preliminary responses to nickel, copper and nitrogen were obtained on 15-year-old trees well supplied with phosphorus. Advisory foliar levels for nitrogen and phosphorus are given.