Qualidade morfofisiológica e nutricional de mudas de açaizeiro (Euterpe oleraceae Mart.) em diferentes proporções de composto de resíduos orgânicos na amazônia.

Abstract

The açaí tree is a palm tree native to the Amazon with great economic importance for regional fruit growing, mainly for the state of Pará, the largest national producer. Due to the economic potential and expansion of the açaí market, the need to produce quality seedlings for the implementation of organic crops in the Amazon arises, which is strictly related to the use of substrate. The use of organic compounds from residues in the formulation of substrates is a practice adopted by many farmers and presents itself as an alternative from an economic and environmental point of view. The objective of this study was to evaluate the morphophysiological quality of açaí seedlings subjected to different proportions of compost with organic residues, aiming at the management of organic production of açaí trees in the Amazon. The experiment was carried out in a nursery at the Federal Rural University of Amazônia, Campus Belém/PA. The organic compost used to compose the substrates came from the Campo Limpo organic community, in the municipality of Santo Antônio do Tauá, resulting from the composting of poultry litter and residues from açaí seeds (Euterpe oleraceae Mart.), andiroba (Carapa guianensis Aubl.), passion fruit (Passiflora edulis Sims) and priprioca (Cyperus articulatus L.). The experiment consisted of a randomized block design, with treatments arranged in a 5x2+1 factorial arrangement, with factor 1 (five proportions of organic compost – 0%, 20%, 40%, 60% and 80%) and factor 2 (with and without the use of liming) and the treatment containing 100% compost. Each treatment had 5 replicates and 3 seedlings. At 6, 8 and 10 months after transplanting, biometric evaluations of the seedlings were performed (plant height, stem diameter, number of leaves, leaf area, root length, root volume, shoot dry mass, dry mass root, robustness index and Dickson quality index) and the chlorophyll index; while at 6 and 10 months the physiological parameters (CO2 assimilation, stomatal conductance to water vapor and transpiration rate) were evaluated. The estimated proportions between 53% and 60% showed the best developments for biometric parameters, quality of seedlings and physiological. The results reveal that the use of organic residues in the formulation of substrates promoted an increase in biometric parameters, seedling quality and physiological indices, proving to be efficient in the production of açaí seedlings, resulting in seedlings with a quality standard for definitive planting at six months.