Rate, Timing, and Slow-release Nitrogen Fertilizers on Bell Peppers and Muskmelon

Abstract

Slow-release methylene urea, sulfur-coated urea, and ammonium sulfate fertilizers were applied at different rates and times on muskmelon ( Cucumis melo var. reticulatus Naud.) and peppers ( Capsicum annuum L.). Increasing N application rate did not affect muskmelon yields, but, in some instances increasing rates up to 134 kg N·ha −1 improved pepper fruit yield and weight. With an increasing N rate, pepper petiole N increased. Timing of fertilizer application did not affect yield of either crop, but application at thinning increased muskmelon fruit weight over preplant application in one instance, whereas the opposite effect occurred in peppers. Split applications and application at thinning increased pepper petiole N content over preplant application in most instances. Early N availability seemed necessary to benefit fruit size and yield, whereas delayed split applications increased only plant N content. Fertilizer source had no effect on either crop in this study. Chemical names used: S-( O-O -diisopropyl phosphorodithionate ester of N -(a-mercaptoethyl)benzene-sulfonamide (bensulide) and N-N -diethyl-2-(1-naphthalenyloxy)propionamide (napropamide).