Effects of urea, ammonium nitrate and superphosphate on establishment of cereals, linseed and rape

Abstract

In pots filled with a loamy sand the degree of harm caused by urea banded with the seed or topdressed on the soil surface, varied with species. The order of susceptibility to germination damage was rape> linseed > > oats > wheat > barley. In addition the emergence of rape and linseed was reduced from about 90 per cent of possible germination to around 50 per cent when superphosphate was banded with the seed. The adverse effect on wheat was greater when the seed bed was moist rather than dry and the effect was reduced when the pots were watered immediately after seeding. On the same soil in the field urea reduced emergence of wheat much more than did ammonium nitrate when both were drilled in contact with the seed.