Abstract
Three fertilizer trials, one on St Ann clay loam and two on Newell clay, were conducted in Jamaica during 1971 to test combinations of N, P and K applied at different levels. On the St Ann clay loam, growth response to fertilizer applied at the lower rates was pronounced, but not yield. The mean fertilizer effect at the higher rates of application was a significant increase of 1089 kg/ha unshelled nuts over control. On Newell clay loam, the effect of fertilizer on yield was significant on only one of the two sites. Nitrogen at its higher level of 67·3 kg/ha had a significant depressing effect compared to the lower level of 33·6 kg/ha. Neither the phosphorus nor the potassium main effects were significant but two of their interactions were.
