Fisiologia do abacaxizeiro 'Vitória' cultivado sob diferentes condições de adubação, no litoral norte da Paraíba

Abstract

The pineapple crop is an important social and economic activity where it is cultivated, but the increase in the inputs price and demand for high quality production has increased the use of alternative fertilizer sources. Then, it was conducted the actual study in order to evaluate the vegetative growth, gas exchange and nutrition of pineapple ‘Vitória’, cultivated under different organic fertilizer sources. The study was accomplished in the Fazenda Guandu, Itapororoca-PB. For growth variables and gas exchange, the experiment was conducted in a randomized block design with three replications, with treatments arranged in a split plot. The treatment consisted of three sources of organic materials (animal manure, poultry manure and mixed manure), four doses of these materials [(100% of N recommended by soil analysis (DRN), 75% DRN, 50% DRN and without fertilization)], which formed the plot. The subplot was formed by presence and absence of green fertilizer. At the same time installed a parcel with mineral fertilizer at the recommended dose for crop. The evaluation times formed the subsubplot. It was evaluated fresh weight, dry weight, length and width of leaves, absolute and relative growth rate, stomatal conductance, transpiration, net photosynthesis, internal carbon concentration, water and carbon use efficiency, SPAD index, leaf and soil nitrogen, phosphorus and potassium content. The results were submitted to analysis of variance, regression and mean test. Regardless of the nitrogen source used, 7.5 g N/plant showed higher growth leaf 'D' of pineapple ‘Vitória’. The highest values of leaf gas exchange were observed in fertilization with 7.5 g N in the absence of green manure, independent of manure used. The highest NPK concentration in the leaves of pineapple ‘Vitória’ was observed at 300 days after planting. There was no correlation between SPAD and N content in the leaves of the pineapple ‘Vitória’. xvi NPK soil content it were highest at 300 days after planting, decreasing at the end of the growth phase. The fertilizer sources used did not change the growth characteristics, gas exchange and nutrition of pineapple ‘Vitória’.