Response of wheat and canola to side banded anhydrous ammonia
Anhydrous ammonia (AA) is generally marketed as the most economical form of fertilizer N available to western Canadian farmers. Application of AA in the fall and spring prior to seeding is a common practice. It was a general recommendation that seeding be delayed for several days after spring application of AA. However, research in the 1980’s has shown that AA can be applied immediately prior to seeding provided that adequate seed - fertilizer separation prevents seed being placed into the ammonia injection zone. Growth in direct seeding practices has increased interest in the adaptation of AA to low disturbance, one-pass, seed and fertilizer application. A research trial was conducted in Saskatchewan and Alberta to determine the potential for precision side band application of Cold-Flo AA at seeding. While AA increased seedling stand damage over that observed with urea for both wheat and canola, no difference was recorded in wheat grain yield from seven field trials. No grain yield difference to N form was recorded at four of the five trials evaluating canola. However, at Melfort canola grain yields were lower for AA than urea, reflecting N loss from the AA applied on these clay soils while wet. Loss of AA on wet clay and silty clay soils resulted in reduced crop N uptake and lowered NUE relative to urea. The results of this study indicate that given adequate seed-fertilizer separation, AA can be safely applied at seeding in a precision side band application. Soil conditions which are known to cause N loss on application of AA, in particular wet clay soils, may benefit more from an alternative N source. Producers interested in adapting this technology to their seeding system are encouraged to conduct their own on-farm evaluation, particularly where they farm lands with rolling to hilly topography which include eroded hill tops.
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