Cumulative Effect of Annual Additions of Undecomposed Leaves and Compost on the Yield of Field-Grown Peppers

For three years, undecomposed leaves were applied on a sandy terrace soil (Windsor) and a loamy upland soil (Mt. Carmel) in spring or fall. Yields of peppers from these plots were compared to yields from plots amended with fully mature leaf compost and unamended controls. In general, the greatest pepper yields were from plots amended at both sites with leaf compost and the smallest yields were from plots amended with leaves in the fall. At both sites, higher yields were due to increased number of peppers/plant. The reduction in yields from plots amended with leaves in the fall appear unrelated to nitrogen immobilization as nitrogen concentrations were greater or similar to the unamended control plots. The possible role of phenol phytotoxicity from the fall applied leaves is discussed.