Frequência de aplicação de nutrientes na produção de mudas enxertadas de cajueiro-anão por sistema floating

Abstract

The cashew tree (Anacardium occidentale L.) is one of the most widespread crops in the country, especially in the northeast of Brazil, and is mainly consumed for its processed nuts (roasted) and stalks. The use of technology in the production of fruit seedlings guarantees good seedling quality and ensures proper orchard management. The aim of this study was to evaluate ways of supplying nutrients for the production of grafted 'CCP 76' dwarf cashew seedlings. For this study, grafted 'CCP 76' cashew seedlings were used, placed in plastic tubes filled with coconut fiber substrate. The experimental design used was completely randomized (DIC), consisting of 6 treatments and 24 replications, the treatments were T0 - water only (control), T1 - nutrient solution 1x per week, T2 - nutrient solution 3x per week, T3 - nutrient solution 5x per week, T4 - nutrient solution 7x per week and T5 - foliar fertilization. The biometric variables analyzed in the seedlings were: plant height (ALT), number of leaves (NF), stem diameter (DC), leaf dry mass (MSF), stem dry mass (MSC), root dry mass (MSR) and leaf area (AF). For the physiological analysis, the data was obtained using an infrared gas analyzer (IRGA), analyzing the transpiration rate (E - mmol H2O m-2 s-1), photosynthesis (A - μmol CO2 m-2 s-1), stomatal conductance (gs - mol m-2 s-1), ratio between internal and external CO2 concentration (Ci/Ca), instantaneous carboxylation efficiency (EiC) and instantaneous water use efficiency (EUA inst.). The frequency of nutrient application 5 times a week via the floating system favored the initial growth of the seedlings and the increase in leaf dry mass.