Trocas gasosas e crescimento inicial de Tabebuia aurea submetida á adubação fosfatada e orgânica.

Abstract

In the recovery of degraded areas under the Caatinga biome, there is a need to adopt a program for the sustainable management of its natural resources, including the maintenance and / or reinsertion of native plants. However, due to the loss of fertility due to the erosion process of these areas, there is a need for prior intervention in soil fertility after the knowledge of the limiting nutrients, so that suitable conditions are created for the establishment of the species to be reintroduced under such conditions . The objective of this study was to evaluate the influence of doses of phosphorus (P) and organic matter (M.O) on the initial growth and physiological aspects of the craibeira (Tabebuia aurea). The work was carried out from October 2016 to April 2017 in a setting of the CCTA / UFCG. The experimental design was a completely randomized design, in a 5 x 2 factorial scheme, with four replications, totaling 40 experimental units. The factors corresponded to five doses of P (0, 100, 150 and 200 mg dm-3) and two doses of organic matter (0 and 50 g/kg). During 120 days, every 15 days, plant height and stem diameter were evaluated. At the end of this period, the dry mass production of the plant, the gas exchanges, the fractions of P in the leaf, the utilization efficiency of P and the P content in the soil were evaluated. P doses gave increases in the gas exchange and initial growth of the no-fodder plants. The addition of organic matter increased the P content in the soil and the initial growth of the crab, except for root dry mass. The soluble phosphorus fractions were not good indicators of the prediction of the phosphate nutrition of the fodder without organic fertilization. With addition of organic matter the Po and Pts were elevated with the doses of phosphorus. The highest EUP (phosphorus utilization efficiency) was in low availability of this nutrient in the soil and with organic matter addition.