Biostimulant potential of Azospirillum brasilense and nicotinamide for hydroponic pumpkin cultivation

Abstract

ABSTRACT The application of biostimulants in agriculture has been studied to increase production while using smaller physical spaces and agricultural inputs to increase sustainability in production systems. Despite the promising results, there is a need to study the effects of joint applications of these products, identifying possible interactions during crop development. Thus, this study aimed to verify the biostimulant potential of the isolated and combined use of nicotinamide and Azospirillum brasilense during the initial growth of pumpkin plants in hydroponic cultivation. A completely randomized design with six treatments and four replicates was performed. The treatments were composed by the combination of the application of nicotinamide (foliar) and A. brasilense (foliar or applied in the hydroponic solution). Treatments increased the gas exchanges, particularly the assimilation rate and carboxylation efficiency, being superior to the control treatment. However, for growth characteristics, the isolated application of nicotinamide favored the development of the shoot and, when combined with A. brasilense via foliar, increased root growth. Thus, the application of nicotinamide and A. brasilense alone or together enhances the growth and gas exchanges of pumpkin plants grown in a hydroponic system, especially when using foliar application of A. brasilense. Whereby its action can be referred to as a biostimulant effect. Furthermore, the application method affects the efficiency and compatibility of the products applied. Therefore, foliar application is recommended.