Fish Emulsions, Cyano-Fertilizer, and Seaweed Extracts Affect Bell Pepper (Capsicum annuum L.) Plant Architecture, Yield, and Fruit Quality

Bell peppers (Capsicum annuum) were grown in a greenhouse to evaluate organic fertilizer and foliar seaweed application effects on plant architecture, yield, and fruit quality. Many organic fertilizers contain phytohormones intrinsically. Hydrolyzed and non-hydrolyzed fish fertilizer and cyano-fertilizer treatments were applied in split applications every 7 days over a 135-day growing period. Control plants received no supplemental N. Each fertilizer treatment received applications of one of two different foliar seaweeds or no foliar seaweed in a 4 × 3 factorial design with three replications. Both hydrolyzed and non-hydrolyzed fish fertilizers and cyano-fertilizer increased the number of branches per plant compared to the N-deficient control. The plants receiving cyano-fertilizer or non-hydrolyzed fish fertilizer yielded more than the N-deficient control, and those treatments received 2–3 times the auxin application as the hydrolyzed fish fertilizer. In addition, the leaves from the plants treated with non-hydrolyzed fish fertilizer contained substantially higher levels of abscisic acid, although no abscisic acid was detected in the fertilizers. Both seaweed products decreased the number of fruits that were “bell”-shaped and increased the number of “long”-shaped fruits. Organic fertilizers are complex matrices of nutrients, phytohormones, and other metabolites, making it very challenging to determine the mechanisms behind the observations.