Desenvolvimento e fisiologia da pimenteira-do- reino submetida a diferentes doses de nitrogênio e potássio via fertirrigação

Abstract

Black pepper is one of the most important spices in the world, responsible for generating jobs and income, the crop has great economic and social importance. Therefore, the need to develop crops not only in terms of quality, but also in productivity makes it necessary to use technolo-gies, among which we can mention the management of fertilization through fertigation. The objective of this work was to evaluate the development of black pepper under different doses of N and K via fertigation. The work was carried out at Empresa de Produtos Tropicais de Castanhal - TROPOC during the months of April 2021 to December 2022. The experiment was in randomized blocks with four doses of N (0, 30, 60, 120 g) and four doses of K (0, 35, 70, 140 g) based on the pepper fertilizer recommendation at 0, 50, 100, 200%. Fertirrigation was carried out every 15 days, its performance consisted of one third of the time used in irrigation, then fertigation occurred and then irrigation occurred again, with the objective of carrying nu-trients to the lower layers of the soil and washing the system of irrigation. The fertilizers used in fertirrigation were purified potassium chloride (60% K), calcium nitrate (15.5% N and 19% Ca), magnesium nitrate (11% N and 9.3% MgO), urea (45% N). Plant Height-AP, Stem Cir-cumference-CC, Node Number- Node Number, Nitrogen Content by the SPAD index at 90, 120 and 150 days after the treatments differentiation, the Photosynthesis analyzer was used - Irga for the analysis of CO2 assimilation rate, Carboxylation efficiency (ECi), gas exchange (gs), Internal CO2 concentration (Ci), transpiration (E) and Internal water use efficiency (WUE). The data were submitted to the F test and regression analysis at 5% and 1% probability, the analyzes were carried out with the aid of the R 4.2.2 program. Black pepper had its growth and physiological activity influenced by different doses of nitrogen and potassium, high doses of fertilizers showed the best response for all analyzed variables, but to determine an economical dose, it is necessary to know the response of the plant the productivity characteristics.