Produção de mudas, revegetação e eficiência nutricional de espécies nativas na recuperação de áreas degradadas no Bioma Mata Atlântica

Abstract

The forest remnants of the Atlantic Forest are well below the original vegetation, and with this increase the occurrence of areas degraded by anthropic activities resulting from economic growth causing removal of the fertile soil layer and exposure of horizons of low fertility. These areas, for the most part, are compacted because they are in the subsurface horizons and with deficits in the nutrient content, making the development of the species impossible. Therefore, in order to be successful in projects for the recovery of degraded areas, quality seedlings are necessary, to use techniques that allow the development of the species in these areas, to know the species that adapt to a particular type of degradation and its nutritional requirements. Aiming at the recovery and management of degraded areas four experiments were developed. In the first experiment the objective was to produce quality seedlings of Canavalia rosea with low cost using different substrates and fertilizers. The levels of fertilization with simple superphosphate, simple superphosphate + micronutrients, NPK 04-14-08 and NPK 04- 14-08 + micronutrients provided seedlings with height, number of leaves, leaf area and total dry mass statistically superior to the seedlings produced without fertilization. The substrate with higher proportion of clay provided higher height, number of leaves and leaf area of the seedlings compared to the sandier substrate. The lowest cost of production of the substrates to produce vigorous seedlings was found on the substrate more clayey with simple superphosphate application. In the second experiment the objective was to evaluate the soil preparation and fertilization levels with NPK 04-14- 08 in the planting of five native species in an area degraded by clay extraction. The type of soil preparation did not influence the development of the species in the field. Fertilization in the planting with NPK 04-14-08 allowed the tested species to adapt to the area degraded by clay extraction, and the species Dalbergia ecastaphyllum and Schinus terebinthifolius showed a more rapid development, while Inga laurina, Protium heptaphyllum and Psidium cattleyanum had a slower development. In the third experiment the objective was to evaluate the growth, biomass production, content and nutritional efficiency of Ipomoea pes-caprae, cultivated in nutrient solution under phosphorus concentrations. Growth and biomass production of I. pes-caprae were not affected by the reduction of the P concentration in the nutrient solution. The macronutrient contents found even at the lowest concentrations of P, are considered satisfactory. The most accumulated and efficiently absorbed nutrients were N, K and Ca, whereas P, S and Mg were the most efficiently used by the species. In the fourth experiment the objective was to propose mathematical equations using linear dimensions to estimate the leaf area of C. rosea. The leaf area of C. rosea can be measured quickly, easily and non-destructively through the product of the multiplication of the length along the main vein with the maximum width of the leaf blade of the last leaflet, by the determined power model equation