The Influence of Fertilizer Placement on Crop and Weed Ecology in Direct-seeding Systems

The rapid expansion of no-till seeding in western Canada has increased demand for information on how the time of fertilizer application and placement methods influence crop yield response. In addition, the amount of soil disturbance associated with fertilizer application and seeding can have a profound effect on the stimulation of weed growth and resulting crop competition.

Variation observed in crop establishment with N fertilizer placement methods was seldom reflected in final grain yields, indicating that large differences in crop stand are required before the final yield of spring wheat or canola can be influenced. Little difference in final grain yield was observed whether fertilizer N was fall or spring band applied or side banded at seeding. However, at the high pH Brandon site, sideband application of N at wide (12-inch) row spacing was found to have a detrimental effect on the establishment and yield of both wheat and canola. Fertilizer timing, fall vs spring application, did influence grain protein in many instances. The improved protein with spring application indicated that there were some over-winter losses of N from the system. Crop water use was rarely influenced by either fertilizer N placement or herbicide rates. In fact, the lack of many significant crop development or yield effects due to herbicide rates used in this study indicates that reducing herbicides was of little agronomic importance. MB-09