Effects of Biostimulants and Fertilizers on Specialty Bell Pepper

An experiment was conducted in July-November 2014 in Mayaguez, Puerto Rico, to determine the effects of biostimulants and fertilization on growth, yield, and quality of ‘Chocolate Beauty’ bell pepper grown in containers in a high tunnel protective structure. The plants were grown in a 3:1 mixture of alluvial soil and sphagnum + perlite mix (Promix® BX), fertilized with either (1) 22.67 kg N-P-K/0.40 ha pre-plant and 45.35 kg N/0.40 ha 10 weeks later using granular urea (=field fertilization recommendation by Ag Experiment Station, UPRM), (2) 22.67 kg N-P-K/0.40 ha pre-plant and 45.35 kg N/0.40 ha divided in 10 applications every 7 days using an urea solution (=greenhouse fertilization), and (3) 22.67 kg N-P-K/0.40 ha from organic 6-6-5-8Ca + 0-0-15-1Ca pre-plant and 45.35 kg N/0.40 ha from organic 6-0-0-8Ca (Bioflora®). Every 14 days the crop leaves were sprayed to run-off with different biostimulant solutions. The biostimulants tried were (1) a blend of amino acids formulated for crops (AA) (Aminoquelant Ca®), at 4 ml/L of water, (2) an extract of the marine alga Ascophyllum nodosum formulated for crops (Stimplex®), at 5 ml/L, (3) a mixture of natural ingredients containing brassinosteroids, vitamins, and enzymes (Vitazyme®), at 10 ml/L of water, and (4) water (control). Fruits were harvested at maturity (color turning from green to chocolate), weighted, quantified, and graded into categories according to their diameter and quality. Total fruit number and weight per plant were affected only by fertilizers, with the soluble treatment resulting in more fruits per plant than the other treatments. Marketable fruit number was significantly lower in plants treated with granular fertilizer. There was a significant interaction between biostimulants and fertilizers on total marketable fruit weight and weight of medium size fruits, with the highest yields resulting from the combination of the alga extract and organic fertilizer. The treatments did not affect the number of non-marketable fruit, but plants treated with granular fertilizer resulted in a larger weight of non-commercial fruits. These results indicate that the yield of this specialty pepper may be regulated with fertilizers and/or combinations of fertilizers and biostimulants. Disclaimer: Mentioning brand names does not imply an endorsement from the authors or from the University, and is done solely to specify the materials used in this research.