Efeito do substrato e fontes de nitrogênio no crescimento inicial de pinhão-manso (Jatropha curcas L.).

Abstract

The Jatropha curcas L., has potentialities for biodiesel production which is a fact that has aroused the interest of researchers in searching of more knowledge about this oilseed. The objective of this work was to study the effect of two different substrates and three nitrogen sources in Jatropha curcas L. seedlings growth. The essay was conducted during 80 days, in 50% shade environment; the treatments were arranged in a factorial 4 x 2, corresponding, respectively, to nitrogen sources and substrates, and were distributed according to the a completely randomized design (DIC) with five replications. The substrates used were: clay soil (S1) and clay soil:sand (1:1 v/v). The nitrogen sources were: ammonium sulfate (N1); calcium nitrate (N2); urea (N3). The data relating to morphological parameters were collected every 15 days, and in the end of the experiment, seedlings were cut at ground level, so as to separate shoot and roots. The plant material was dried at 65 °C, to constant weight, and then the levels of nitrogen (N), phosphorus (P) and potassium (K) were evaluated. Both substrate and nitrogen source influenced the morphological parameters of Jatropha curcas L. in its seedlings stage, so that the substrate composed of clay soil and sand (1:1 v/v) ensured better crop establishment, the nitrogen fertilization affected the relative shoot / root ratio. Calcium nitrate and urea influenced the foliar accumulation of N, P and K; and were responsible for the best morphological responses of the Jatropha curcas L.