Crescimento inicial do pinhão-manso (Jatropha curcas L.) submetido a regimes hídricos em duas classes de solos

Abstract

The present work has as goal analyzing the effect of different water regimes on the initial growth of physic nut. Two experiments were conducted under greenhouse conditions of the Embrapa Western Agriculture, located in Dourados, Mato Grosso do Sul State, Brazil. At the first using dystrophic Red Latosol, and at the second dystroferric Red Latosol. In both experiments, the treatments corresponded to water regimes stipulated in 20, 40, 60, 80 e 100% of the soil water retention capacity. The experimental design adopted was completely randomized with five treatments (water regimes) and five replicates. Each replicate corresponded to one plant cultivated in polyethylene pots containing 5 dm3 of dystrophic Red Latosol or dystroferric Red Latosol, collected at the Jatiuca farm in Anastacio, MS, and at the experimental area of the Embrapa Western Agriculture, in Dourados, MS, respectively. At the two experiments the evaluations of plants height, stem diameter, number of leaves and chlorophyll content were performed in six dates. Already dry mass of the leaves, petioles, stems and roots were determined at the end of the experiments. At the first experiment, were also evaluated the stomatal conductance, transpiration and photosynthetic rate, who were determined in two dates. And at the end of second experiment were also evaluated the leaf area and the volume of root of all plants. The water regimes of 60 and 80% of the soil water retention capacity provide the best responses to the physiological variables and of growth to the culture of physic nut in dystrophic Red Latosol. The water regimes superiors the 80 % of the soil water retention capacity propiciated the plants of physic nut highest growth in height, stem diameter, number of leaves, leaf area, chlorophyll and dry masses in dystroferric Red Latosol.