RESPONSE OF RAPESEED TO APPLIED NITROGEN, PHOSPHORUS, POTASSIUM AND SULFUR WHEN GROWN ABOVE 57 DEGREES NORTH LATITUDE

In a two-year study at three soil sites, 14 fertilizer treatments were applied to rapeseed grown on summerfallow. Phosphorus applied singly or in combination with N, with N and K, or with N, K and S significantly increased seed yields on a Rego Humic Gleysol soil of low pH status and on an Orthic Dark Gray Wooded soil of high available N content; there was no fertilizer response on a Rego Gleysol soil of variable texture and high available P content. While rapeseed did not respond to N alone, additional benefits did sometimes accrue from the addition of 11 kg/ha of N to P applications.