Nutrient status and soil properties in areas of the Benalla, Trentham and Rennick Nurseries producing 1-0 Pinus radiata seedlings in 1975.  P. Hopmans and D. W. Flinn.  April 1979.  14 pp. (unpubl.)

SUMMARY

Nutrient status and soil properties in areas of the Benalla, Trentham and Rennick nurseries producing 1-0 Pinus radiata (D. Don) seedlings in 1975 were determined from soil and seedling samples taken at the time of lifting. The objectives were firstly to determine the nutrient status of the seedlings and to recommend a fertiliser regime to ensure a balanced nutrient supply, and secondly to detect any deterioration in physical and chemical soil properties due to continuous cropping and if required to recommend ameliorative treatments so that productivity is maintained.

At Benalla nitrogen and magnesium levels in this seedling tops were generally less than desirable, particularly in Blocks 8A and 8B where magnesium concentrations in the seedling tops were frequently deficient. Nitrogen and potassium levels in seedling tops were lower than for previous crops and this together with high concentrations of sulphate and phosphorus in the tops was largely attributed to an imbalanced fertiliser regime. Soil results for this nursery showed that frequent green cropping has at least maintained levels of organic carbon and nitrogen in the soil and prevented a decline in soil structure. Improvement in soil structure however continues to be a high priority in this nursery.

At Trentham magnesium concentrations in the seedling tops approached deficiency levels which was largely due to an inadequate input of magnesium fertiliser. The application of gypsum has reduced undesirably high aluminium levels in the seedling tops, but an expected increase in sulphate levels did not occur. Soil results indicate that, as at Benalla, green cropping in this nursery has maintained levels of organic carbon in the soil.

At Rennick fertiliser input of potassium and magnesium was well below the requirement of the seedling crop and consequently levels of these elements in seedling tops were less than desirable. Sulphate and iron concentrations in seedling tops were also less than desirable. Soil results indicate the green cropping in this nursery might not be as successful in maintaining levels of organic carbon as in the other nurseries and the importance of identifying a suitable green cropping regime is stressed. The use of nitrogen applied at the time each green crop is incorporated into the soil is advocated to promote decomposition of the organic material.

A recommended fertiliser regime for all nurseries was derived from the estimated nutrient removal in the 1975 P. radiata crop and consists of a pre-sowing broadcast application of Blood and Bone (1000 kg/ha), Pivot 200 (500 kg/ha) and magnesium sulphate (200 kg/ha) incorporated into the beds, followed by monthly applications during the growing season of magnesium sulphate (50 kg/ha), Aquasol (10 kg/ha) and Nitrophoska Blue Special (10 kg/ha).

Also published:

Flinn, D.W., Hopmans, P. and Craig, F.G. (1980)  Survey of the nutrient status of Pinus radiata seedlings and of soil properties in three Victorian nurseries.  Aust. For. 45 (1): 58-66.