Adubação sulfatada no crambe (Crambe abssynica Hoechst) e seus efeitos no crescimento, no enxofre absorvido e recuperado por extratores químicos

Abstract

The study aimed to evaluate the use of sulfur in the crambe crop under sulphate fertilization and its relations with sulfur availability in a Rhodic Acrustox (LVdf) and an Typic Haplorthox (LVd). The experiments were conducted in greenhouse and in the Laboratory of Soil Fertility, in the Federal University of Grande Dourados, Dourados-MS, from March to October 2009. The experimental design utilized was the completely randomized, in a factorial scheme 2 x 6 with four replications, which factors were two classes of soil (LVdf and LVd), and six doses of sulfur (0, 15, 30, 60, 90 and 120 mg dm-3 S). To study the use of the S by plants of crambe, when the plants were at maximum flowering, were evaluated for height of plants, dry matter of shoots and roots, S content in shoots and roots, the accumulation of S in shoots and roots, and calculated the indices of efficiency of utilization, absorption and translocation of S. The assessment of S recovered in soils was determined by the chemical extractors Ca(H2PO4)2 500 mg L-1 P in HOAc 2 mol L-1, Ca(H2PO4)2 500 mg L-1 P in H2O and CaCl2 10 mmol L-1. In soils with low availability of S the crambe crop showed deficiency symptoms, highlighting the need to use appropriate doses for the better plants development. It was found that application of doses up to 40 mg dm-3 S, increased the growth and dry matter production of crambe. To assess the availability of S, it is recommended to use the extractor Ca(H2PO4)2 in H2O, since this extractor has practicality in routine laboratory and recover soil concentrations of S which are correlated with the amounts of S absorbed by plants.