Marcha de absorção de nutrientes e crescimento do abacaxizeiro Vitória irrigado

Abstract

Knowing on the growth and mineral nutrition of pineapple is fundamental for its correct management. Thus, this work aimed to evaluate the vegetative growth, absorption and accumulation of nutrients in the 'Vitória' pineapple under irrigated conditions of the semiarid. The used statistical design was in blocks at random, with four repetitions. The treatments were defined for nine times of sampling of plants and their components (270, 330, 390, 450, 510, 570, 690, 750 and 810 days after planting (DAP). During the study period and for each sampling time the following characteristics were appraised: plants height, stem diameter, length of the D leaf, accumulation of fresh and dry matter of the different compartments of the plant, total and vegetative biomass, production of fruits, absorption, accumulation and export of macro and micronutrients in the crop. The results were submitted to analysis of variance and in the presence of significant differences (p < 0.001), models of no-lineal regression were adjusted. By means of relative production of vegetative biomass five phenological stages of pineapple growth were proposed: up to 20% of production of biomass-V1; 21-40%-V2; 41-60% - V3; 61-80% - V4; above 80% - V5. Most of the growth characteristics, as plants height, length of the D leaf, stem diameter and biomass production in the plant components presented slow initial increment (in the phenological stage V1), and attributed to the smallest size and type of planting material used. The maximum accumulation of vegetative biomass occurred between the stages V4 and V5. The leaves were responsible for the final production of 54 to 47% of total biomass of fresh and dry matter, respectively. The rates of relative growth were larger in the stage V1 and they decreased with the cultivation time, however the rates of maximum accumulation were observed at the stages V4 and V5, resulting in the final production of 72 t ha¹ of fruits and 326 t ha of plant biomass (fresh matter). O medium content of macro and micronutrients absorbed by the 'Vitória' pineapple was considered superior to those found in the literature. Leaves and stem were the plant components that presented larger nutrients accumulation. The macronutrients accumulation in the 'Vitória' pineapple presented the following decreasing order: K > N > S > Ca >Mg >P. However, the macronutrients export for the pineapple fruit followed the following decreasing order: K>N>S>Ca>P>Mg. For micronutrients, the total accumulation presented the following decreasing order: Fe>Zn>Mn>Cu. However, the macronutrients export for the pineapple fruit followed the following decreasing order: Zn>Fe>Cu > Mn. The contents of nutrients exported by the fruits represented important component of nutrients extraction of the soil that should be returned, while the nutrients contained in the leaves, stem and root can be incorporate to soil inside of a program of plant residues resorption.