HortTechnology (Dec 2024)
Effect of Nitrogen Concentration on Compact Tomato and Pepper Plants during Production and Fruiting Phases
Abstract
The objective of this study was to compare the growth, quality, and yield of compact tomato (Solanum lycopersicum) and pepper (Capsicum annuum) plants using different nitrogen (N) concentrations from a complete fertilizer solution (15N–2.2P–12.5K with micronutrients). Two experiments were conducted in separate locations (Florida and Indiana). During each experiment, tomato and pepper plants were hand-irrigated during production phases that lasted 7 and 9 weeks, respectively, with fertilizer solutions containing 0, 50, 100, 150, or 200 mg·L−1 N applied with each irrigation event (Expt. 1) or every other irrigation event (Expt. 2). In both experiments, the N concentration either increased or remained constant during a fruiting phase during which tomato and pepper plants were grown for an additional 8 and 10 weeks, respectively. Growth and yield results were generally similar between the two experiments. Overall, plants that received a lower N concentration during both production and fruiting phases tended to be shorter, had a smaller growth index, and produced a lower fruit yield compared to those treated with a higher N concentration. Plant greenness, measured as either SPAD index or chlorophyll concentration, was generally lower in plants that received a lower N concentration during the production phases and maintained a similar pattern during the fruiting phases. However, at the end of both experiments, the greenness of plants that received 0/150 mg·L−1 N (concentrations used during production and fruiting phases, respectively) tended to be higher than that of those treated with 50/50 mg·L−1 N. Fruit yield was generally lowest for plants from both species treated with either 0/150 or 50/50 mg·L−1 N. In general, tomato plants treated with ≥100/100 mg·L−1 N had a similar fruit yield. However, the yield of pepper plants tended to increase with higher N concentrations during both the production and fruiting phases. Intumescence of pepper plants also increased with a higher N concentration, but there were different responses between the two experiments, suggesting that the growing environment plays a role during the development of the disorder. Overall, our findings showed that reducing the initial N concentration is a potential strategy for producing short tomato and pepper plants with a small growth index, but that the postproduction yield will likely decrease as the N concentrations are reduced during production.
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