Effect of nitrogen,phosphorus and potassium on yields and nutrient levels in onions grown on a sphagnum peat soil

Abstract

Onions were grown on two areas of sphagnum peat. One (old area) had been fertilized and cropped for a 5‐year period and the other (new area) had not. Fertilizer treatments on both areas consisted of an N, a P and a K series. Each nutrient was applied at four rates in combination with constant rates of the other two.

In practically all instances comparable treatments resulted in lower N, P and K levels in plant tissue samples from the new area than from the old where residual effects from previous cropping and fertilization were evident. Yield data indicate that initially, previously unfertilized sphagnum peat should receive N, P and K at 275–300, 40–50 and 70–80 kg/ha respectively.