Response of bean cultivars to sulphur

Abstract

The present experiment was carried out under greenhouse conditions at the Soil Science Department of Universidade Federal de Lavras (UFLA), using a Dark-Red Latosol (Oxisol), medium texture, cerrado phase, from Itumirim municipality, MG, Brazil. The objective of this research was to evaluate the effects of sulphur rates in the growth of different bean (Phaseolus vulgaris L.) cultivars, and to determine the critic levels of S in the shoots. The treatments consisted of four S rates (0, 30, 60 and 120 mg/kg soil) and three bean cultivars (Carioca, Ouro and H-4), arranged in a completely randomized design, replicated three times. The cultivars showed significant responses in shoot dry matter (SDM) production when S was applied; however, the gains in SDM varied according to the cultivar. Except for the H-4 cultivar, the S fertilization also increased the root dry matter production, but with lower increases than that observed for the SDM. The N/S and P/S relations, as well as the critic levels of S in the SDM, corresponding to 90% of the maximum SDM, varied among cultivars. The N/S relations in the SDM were 20.97, 20.81 and 18.68, whereas the P/S relations were 2.24, 1.33 and 0.87, respectively in the Carioca, Ouro and H-4 bean cultivars. The critic levels of S in the SDM were 1.89, 2.21 and 2.16 g of S/kg, for Carioca, Ouro and H-4 bean cultivar, respectively. The S utilization efficiency at the S doses enough to reach 90% of the maximum SDM varied according to the bean cultivars, showing that the selection and breeding of the genetic material adapted to different S soil availability is possible.