Efeito das diferentes concentrações de nutrientes no crescimento do açaizeiro (Euterpe precatorio Mart.)

Abstract

The species Euterpe precatoria Mart. It is native to the western Brazilian Amazon. Its fruit has important nutritional characteristics and antioxidant action superior to Euterpe oleracea Mart .. The production is closely linked to the richness of the soils used and it is known that the Amazonian soils are known to have low chemical fertility and those of lowland areas provide better conditions for management, despite the risks of leaching and immobilization of the main macronutrients. The objective of this research was to evaluate the initial field installation phase in different N-K fertilization arrangements of E. precatoria Mart. seedlings in a land area in the Central Amazon. Planting was followed for 7 months between February and August 2019. The experimental design was a randomized block design with two replications in a 4 x 2 factorial scheme (4 nitrogen levels and 2 potassium levels) and 2 additional treatments with one third potassium level (N2K3 and N3K3). Fifteen seedlings were randomly selected for initial characterization by biometric measurements, relative chlorophyll content (SPAD), leaf nutrient content and dry biomass. Seedling growth in the field was evaluated by biometric measurements and relative chlorophyll contents. The mortality rate was also evaluated. After 7 months in the field, the seedlings of E. precatoria Mart. did not present significant difference, in relation to the applied treatments, for the height, stem diameter, increase in the stem diameter and number of leaves emitted. The increases in height and relative chlorophyll contents showed significant difference between treatments, however, the treatment with lower and higher nutrient concentration did not present statistically significant difference, revealing possible absence of fertilization influence. The mortality index of E. precatoria Mart. seedlings was 11.17%. Thus presenting a low mortality rate when cultivated during the rainy season, after 7 months in the field, in an area of Central Amazonia and in the second year of life, the species E. precatoria Mart. did not show significant responses to the different N-K treatments applied. Keywords: Assai Planting; Initial Growth; NK Fertilization.