Optimal time and placement of nitrogen fertilizer with direct and conventionally seeded winter wheat

Abstract

Direct seeding of winter wheat ( Triticum aestivum L.) has rapidly become an accepted practice in the Chinook region of the southwestern Canadian prairies. Continuously cropped Chernozemic soils are frequently N deficient. To determine best N fertilizer management practices, we examined conventional versus direct seeding to establish winter wheat and to determine the effects of banded and seed-placed N fertilizer treatments in the fall versus broadcast N in the s pring. The research was conducted using two experiments. The first experiment compared band placement of N fertilizer in soil that was conventionally cultivated and seeded, to direct seeding with seed placement of fertilizer using 10% and 50% seedbed utilizations. The second experiment determined optimal time of N application (i.e., fall/spring split vs. spring only) for direct seeded winter wheat. Direct seeding proved to be successful for germination and emergence of winter wheat and was either as good as or superior to conventionally tilled and seeded treatments. Nitrogen fertilizer was successfully applied in the fall without increased risk of winterkill and application at the time of seeding was generally equal or superior to spring broadcast N. Based on these results, producers could either apply all N fertilizer at the time of seeding or use a split application strategy by applying a portion of N in the fall, and in the spring apply the remaining N required, based on soil test N and spring soil moist re conditions. Key Words: Winter wheat, ammonium nitrate, urea, nitrogen fertilizer placement, direct seeding, conventional seeding