Effect of nitrogen, phosphorus and potassium on yields and nutrient levels in carrots grown on sphagnum peat and mineral soils.

Abstract

Abstract Carrots, Daucus carota L., were grown on both sphagnum peat and mineral soils from 1969 to 1972 inclusive. Fertilizer treatments consisted of three rates of N, of P and of K applied in all possible combinations. In practically every instance rates of N, P and K applied to sphagnum peat were reflected in the levels of these nutrients found in carrot leaves. This was not the case with mineral soils. On sphagnum peat there were eight opportunities, and on mineral soils seven, for each of the three applied nutrients to influence yields. On peat N increased yields in three instances, P in one and K in five. On mineral soils N decreased yields in two instances, P decreased them in one and increased them in one while K had no effect. The results suggest that on sphagnum peat carrots may require N, P and K up to 250, 50 and 150 kg/ha respectively whereas on mineral soils maximum rates would be 25, 25 and 50 kg/ha.