THE INFLUENCE OF A COMMERCIAL FERTILIZER TREATMENT ON WEED COMPETITION IN SPRING SOWN WHEAT

Abstract

Applications of ammonium phosphate fertilizer (11-48-0) at 40 pounds per acre on six farm fields in Manitoba were effective in reducing losses in wheat yields caused by weed competition. Average losses in yield due to weed competition were 20.5 per cent in unfertilized portions of the fields and only 11.7 per cent in fertilized portions of the same fields. Increases in wheat yields resulting from fertilizer treatment were approximately equal to increases resulting from weed removal. However, higher yields resulting from fertilizer treatment were sometimes accompanied by decreases in the protein content of the harvested crop. Increased yields resulting from weed removal were generally accompanied by significant increases in the protein content. The combined effects of fertilizer treatment and of weed removal produced the largest increases in yield of wheat and maintained the protein content at a comparatively high level.