Fertilization of Poplar Plantations
- Our stock trials (NSERC) are fertilized at rates of 0 and 150 kg N ha-1 of ammonium nitrate, which is applied in separate plots in year 2 (2003) and year 4 (2005) to determine the optimum timing of early fertilization for hybrid poplar.
- To date the stock trials have not demonstrated enhanced growth due to fertilization after year 2. Preliminary tissue analysis suggest a possible P (phosphorous) deficiency, which would render the added N ineffective. As well, the persistence of weeds in these plots increases competition for N.
- Our clonal trials (SFC) are fertilized at rates of 0, 150, and 300 kg N ha-1 of ammonium nitrate, which is applied annually for the first 5 years to determine the maximum growth potential for juvenile hybrid poplar in Saskatchewan.
- To date the clonal trials have likewise exhibited minimal growth response to increased N levels. Because the clonal trials are situated at the same sites as the stock trials, a possible P deficiency is the most reasonable explanation.