Preplant slow-release nitrogen fertilizers produce similar bell pepper yields as split applications of soluble fertilizer

Slow-release N materials are used to reduce N leaching losses from sandy soils and extend N availability over a growing season. The objective of this research was to examine the effectiveness of preplant sulfur-coated urea (SCU) and polyolefin resin-coated urea (PCU) N fertilizers compared to split applications of soluble fertilizer on green bell pepper (Capsicum annuum L.) yield and quality. The 3-yr experiment consisted of green bell peppers grown on 15-cm raised beds utilizing plastic mulch and drip irrigation. Treatments were N source (preplant SCU, preplant PCU, and fertigated ammonium nitrate) and N rate (90, 135, 180, or 225 kg N ha(-1)). Ammonium nitrate (AN) was applied as a split application, with 20% preplant and 80% applied every-other week in five equal applications. Other N sources were applied 100% preplant, A zero N control was also included. Collected data included plant height, leaf N content, and fruit yield and quality. In two of three years pepper yield was maximized at or near the Alabama recommended rate of 135 kg N ha(-1). Nitrogen source rarely affected the partitioning of harvested peppers into grade groups, Adding N from any N source decreased percent nonmarketable yield (cull) and increased the percentage of marketable yield that was large (U.S. 1) peppers. There were few consistent differences in pepper yield or quality due to N source. Given cost considerations of drip application and N sources, slow-release N materials may be a viable option for small-scale growers not using drip application systems.