EFFECT OF NITROGEN AND PHOSPHORUS FERTILIZATION ON WILD OATS AND SPRING WHEAT

Abstract

Spring wheat, with fertilizer applied in the drill rows, was grown in wild-oat-infested stubble on a Shallow Lethbride loam soil for 4 years, Phosphorus had no measurable effect on the height, straw weight, seed yield, or number of wild-oat plants. In contrast, nitrogen increased the number of seed-bearing stems, plant height, straw weight, and seed yield, but did not change the wild-oat stand. Wheat yields were increased by nitrogen and further increased by the addition of phosphorus at the rate of 20 pounds of P2O5 per acre in 3 of the 4 years. Measured bushel weight of the wheat increased with nitrogen fertilizer additions and was further increased by phosphorus except at the high rate of both materials. Fertilizer applications, under conditions similar to those encountered in this test, may be useful for increasing wheat production, but only at the expense of producing increased quantities of wild-oat seed.