GROWTH RATES OF CATINGUEIRA SEEDLINGS SUBMITTED TO DIFFERENT SUBSTRATES AND SHADING

Caesalpinia pyramidalis Tul. is a native species from the caatinga biome, with a great resistance to drought and great economic potential. However, there is no information regarding the development of this species under different substrates and light intensities, the major environmental factors that influence forest seedling growth. The objective of this work was to evaluate the effect of different shadings and substrates on the growth rates of C. pyramidalis seedlings. The experiment was carried out at the Universidade do Estado da Bahia and Embrapa Semi-Arido. The seeds were sowed in recipients filled with different substrates: soil, sand, soil+ sand, soil+ sand+ goat manure and commercial substrate. The recipients were maintained under different shadings: sunlight (no shading) and at 30%, 50% and 75% shadings. 30, 60 and 100 days after the emergence stabilization, the seedlings were evaluated as to the absolute growth rate, relative growth rate, net assimilation rate, leaf area ratio, specific leaf area, specific leaf weight and leaf weight ratio. There was no interaction between the two studied factors for any growth rate. Under the conditions of this work, it is possible to conclude that, in general, the growth rates of C. pyramidalis seedlings were not influenced by shading and that the soil collected in the caatinga region, associated or not, to sand and manure, allowed a higher growth.