Sombreamento e adubação nitrogenada influenciando acúmulo de biomassa em palma forrageira cv. miúda (Nopalea cochenillifera (L) Salm-Dick)

Abstract

Nopalea cochenillifera cv. Miúda is a widely cultivated cactus forage in the Brazilian semi-arid zone that covers the states of Alagoas, Pernambuco and Sergipe. In spite of having approximately a century of its presence in this region like fodder plant, is still little studied in what concerns its capacity of use for other porpuses and in other forms. In the regions mentioned above, it is very common to observe this plant developing very well under the canopy of some arboreal plants, such as algaroba (Prosopis spp) or even umbuzeiro (Spondias tuberosa L.), however, it is an eventual and unplanned event, however, reveals the ability of Nopalea cochenillifera Saml Dick to adapt to the shadow condition. The objective of this work was to evaluate the biomass production and adaptation to shading through the investigation of the behavior of physiological and biometric variables inherent to the CAM plant, forage palm cv. (Nopalea cochenillifera Salm - Dick) submitted to various levels of shading and nitrogen fertilization. The experiment was carried out in a field in the Agrarian Sciences Center of the Federal University of Alagoas, in a 4 x 2 factorial scheme, in a randomized block design, with four replications, with four levels of shading (0%, 30%, 40%, 70% ) and two levels of nitrogen fertilization (0 and 200 kg of N / ha). the shadow effect produced by bamboo supports with sombrite canvas on each parcel. The following biometric variables were analyzed: cladodes width and length, plant height and diameter, cladode area, cladode area index, number of cladodes per plant, dry matter and dry matter of plants. As for physiological variables, fluorescence of chlorophyll a (Fv / Fm and Yield), nocturnal acidity, chlorophyll and carotenoid, cladode and soil temperature and percentage of cladode nitrogen were measured. The results showedthatNopaleacochenilliferapresentsphenotypeplasticityforadaptationtoshade. However, the treatment with plants in full sun was where the plant had the highest value of accumulation of dry matter, reaching the equivalent of 9.57 tons per hectare 374 after planting.