“Relação N:K e bioestimulante vegetal na morfofisiologia e na produção do pimentão

Abstract

Capsicum annuum L. pepper is a crop that plays a prominent role in the Brazilian economic context, being very demanding on the macronutrients Nitrogen (N) and Potassium (K) due to their importance in the development of the crop. Thus, the use of different managements in the production of vegetable crops can result in increases in productivity, such as the plant biostimulant that is designed for plants and aims to increase nutritional efficiency. In this context, the objective was to test the effects of N: K fertilization and doses of biostimulants on the agronomic characteristics and production of sweet pepper C. annuum in the field. The research was carried out from March to July 2020, at Engenho Triunfo rural area in the municipality of Areia-PB. The study was developed, addressing the aspects explained above, being divided into three articles. In article I, the N:K ratios and application of doses of plant biostimulant in sweet pepper production were studied. In the first experiment, the interaction of N:K and Biostimulant Doses (A×B) had a significant effect for all studied characteristics, number of fruits per plot, average fruit weight, length and diameter, number of immature fruits, production and productivity. For this research it is recommended the 3:1 interaction (75% N 25% K) and the 4.5 mL dose of biostimulant in the production of C. annuum and increase the biostimulant doses to find the best dose with the studied interaction, aiming at the production and maximum productivity of the pepper crop under the conditions of this experiment. In article II, the effect of fertilization with N:K and doses of biostimulant on the growth of C. annuum was evaluated. the interaction of the N:K ratio and Biostimulant Doses (A×B) had a significant effect for all analyzed variables, namely: Plant height, stem diameter, leaf area index, leaf area, absolute growth rate, assimilation rate liquid, Leaves dry mass, Stem dry mass and Total dry mass. The 1:1 N:K ratio was the most suitable for growth, diameter and height, in the 4.5 mL dose of Stimulate®. As for leaf area and leaf area index, doses of 2.8 mL and 2.2 mL of biostimulant in 3:1 and 2:1 ratios are indicated. As for the dry mass of the leaves, the N:K ratio of 2:1 was favorable at the dose of 3.4 mL of Stimulate®. For stem dry mass and total dry mass, the N:K ratio of 2:1, and a dose of 4.5 mL of the biostimulant can be indicated for the conditions of this research. In the article III we studied the chlorophyll fluorescence: initial, maximum, variable fluorescence. And the chlorophyll indices: a, b and total chlorophylls. By analysis of variance it was observed that there was no significant effect on the interaction of factors, doses of biostimulant and N:K ratios, as well as no significant effect for both isolated factors on photochemical activity and photosynthetic pigments of pepper at 30 and 60 days after planting (DAP). The use of 1:2 and 2:1 N:K ratios did not require the use of the biostimulant for greater chlorophyll fluorescence and chlorophyll pigment synthesis.