The effects of superphosphate and contour ripping on mortality and first-year height growth of Pinus radiata outplants at Scarsdale.  F.G. Craig and L.J. Bren.  January 1972.  10 pp. (unpubl.)

SUMMARY

1. Superphosphate and contour ripping had no marked or consistent effect on first-year mortality of radiata outplants at Scarsdale.
2. Contour ripping alone had little effect on first-year height growth, and cannot be justified as a single treatment.
3. Superphosphate alone, at 5 ozs. per tree, gave nearly twice the first-year height growth of unfertilized controls. No worthwhile further increase in height growth was achieved at higher application rates.
4. Superphosphate combined with ripping was the most effective treatment tested. After ripping, 5 ozs. of superphosphate per tree gave about 2.5 times the height growth of unripped, unfertilized controls. This procedure is recommended for present operational practice at Scarsdale. Higher rates of superphosphate gave an additional increase in height growth, but are not recommended yet for operational practice.
5. There was no evidence of consistent variation in mortality or height growth with slope position, so that it is presently recommended that all sites receive the same operational treatment.