TOMATO FRUIT YIELD RESPONSE TO NITROGEN-SOURCE AND PERCENTAGE OF DRIP-APPLIED OR BAND-APPLIED NITROGEN ASSOCIATED WITH LEAF POTASSIUM CONCENTRATION

Field experiments were conducted during the spring and fall of 1994 to evaluate two nitrogen (N) sources [ammonium nitrate (AN) and polymer- coated urea (PCU)] and five levels of drip-or band-applied N on the yi eld of drip irrigated 'Solar Set' tomatoes (Lycopersicon esculentum Mi ll). Early-season yields obtained with PCU were similar to or greater than yields obtained with AN. Highest yields of large fruit early in t he season were produced with 100% preplant-applied AN or 100% band-app lied PCU. Total-season yields were greater with AN than PCU and were n ot affected by placement of N. Increasing the percentage of drip-or ba nd-applied N resulted in leaf N concentrations that were inconsistent with trends in marketable fruit production; however, trends in leaf K concentration early in the season were similar to those of early-seaso n large fruit yields.