The field performance of chlorotic Pinus radiata seedlings raised in burnt soil and soil subject to waterlogging.  G. Minko and P. Hopmans.  October 1975.  10 pp. (unpubl.)

SUMMARY

In the past all chlorotic Pinus radiata seedlings raised in the Benalla nursery were culled prior to planting. The two main areas in which such seedlings occur at Benalla are in soil which has been severely burnt following clearing operations, and in waterlogged areas. In this study a number of characteristics of chlorotic seedlings from this site types were determined at lifting together with healthy green seedlings from adjacent rows, and their mortality and growth as outplants at Ovens plantation compared.

The study indicated that chlorosis of seedlings from burnt soil was probably due to mild nitrogen deficiency, but in other respects, except mycorrhizae numbers, they were similar to healthy seedlings. The numbers of mycorrhizae on chlorotic seedlings from burnt soil were in fact significantly greater than for healthy seedlings from unburnt soil.

In the field, mortality and growth of seedlings from burnt and unburnt soil were not significantly different, and it is apparent therefore that chlorotic seedlings from burnt soil in the Benalla nursery have good establishment potential and should not be culled because they chlorotic.

On the other hand, chlorotic seedlings from waterlogged soil in the nursery exhibited significantly poorer root development, and much lower nutrient reserves in their tops than healthy seedlings from well-drained soil. The elements nitrogen and phosphorus were critically deficient in these seedlings, and their survival and growth were significantly poorer as outplants in the field. It appears therefore that chlorotic seedlings from waterlogged soil at Benalla have low establishment potential, and should be culled prior to outplanting.

Also published:

Minko, G. and Hopmans, P. (1975)  The field performance of chlorotic Pinus radiata seedlings raised in burnt soil and soil subject to waterlogging.  For. Comm. Vic., For. Tech. Pap. 23: 25-30.