Maximum Productivity Study

– Treatment Description –

Within each of the eight installations, six treatments are replicated three times for a total of 18,  0.164-ha treatment plots.
The six treatments are:

1. Control (i.e., not fertilized)
2. NB – fertilize every 6 years with (kg/ha):
        200N, 1.5B
3. NSB – fertilize every 6 years with (kg/ha):
        200N, 50S, 1.5B
4. Complete – fertilize every 6 years with (kg/ha):
        200N, 100P, 100K, 50S, 25Mg, 1.5B
5. ON1 – yearly fertilization to maintain foliar N concentration
        at 1.3% and other nutrients in balance with foliar N
6. ON2 – yearly fertilization to maintain foliar N concentration
        at 1.6% and other nutrients in balance with N

Boron (B) is added to treatments 2), 3), and 4) to safeguard against the possibility of B deficiencies induced by repeated N additions. Treatments 3) and 4) are included to test for incremental growth responses attributable to S and other added nutrients. Previous studies have clearly documented B and S deficiencies in interior forests.

The ON1 and ON2 treatments are patterned after Scots pine and Norway spruce "optimum nutrition" experiments in Sweden and Canada, in which N is added frequently in order to maintain elevated foliar N levels. The ON1 and ON2 treatment plots typically receive 50-100 and 100-200 kg N/ha, respectively, each spring. Other nutrients (e.g., P, K, Mg, S, B) are included periodically to provide an appropriate nutrient balance and to minimize growth limitations caused by secondary nutrient deficiencies. Yearly fertilizer prescriptions for ON1 and ON2 treatments are developed following foliar sampling and nutrient analysis each fall.

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Last Modified: 2007 APR 20.  Ministry contact: Frank van Thienen
Webmaster: For.Prodres@gov.bc.ca