Nutrient survey of guaraná (Paullinia cupana var. sorbilis Ducke) on Maués city - Amazonas state, Brazil

Abstract

One experiment on the nutrition of guaraná (Paullinia cupana var. sorbilis) were conducted in the State of Amazonas with the purpose of studying the effects of supply of nutrients in the fruit production. The objective was accomplished using commercial plantations located at four different sites, two of which were fertilized. Forty mature plants (25 years old, approximately) were considered in each site for experimental purposes. Soil, leaf and fruit samples were collected in each site and chemically analysed as to their nutrient content. Data on fruit production was also collected. No effect was observed in the fertilized sites as to fruit production and leaf macronutrient concentration. Correlations between leaf macronutrient concentration and fruit production indicated a limiting effect due to N, P, Ca and Mg. Calcium and magnesium leaf contents were considerably lower in the mature plant as compared to that of the seedlings.