Resumo

CARCIOCHI, Walter Daniel; CONTRERAS, Lucas Ezequiel; CRESPO, Cecilia  e  BARBIERI, Pablo Andrés. Cover crops: effect on sulfur availability in soybean. Cienc. suelo [online]. 2019, vol.37, n.2, pp.269-280. ISSN 1850-2067.

Selecting the cover crop (CC) specie may affect sulfur (S) availability for the succeeding soybean (Glycine max (L.) Merr.) crop. Thus, the objective of this work was to evaluate the effect of oat (Avena sativa L.) and vetch (Vicia villosa Roth.) as CC and S fertilization on some parameters that define S availability and yield in the succeeding soybean. Three field experiments were conducted in different areas of southeastern Buenos Aires province, where the combination of three levels of CC (oats, vetch, and a control without CC) with two levels of S fertilization (0 and 15 kg S ha^-1) was evaluated in soybean. Determinations included: SO₄ ^-2-S content in soil (0-60 cm) at soybean sowing, greenness index (IV) at the beginning of flowering (R1), and seed yield. The main results were: i) CC accumulated between 7 and 17 kg S ha^-1, allowing reductions of S losses by leaching during the winter fallow, ii) vetch increased S availability in the soil at soybean planting by 28 kg S ha^-1, compared to oat and the control, iii) soybean IV was lower when preceded by oat compared to vetch and the control, iv) there was no yield response to S fertilization, v) in two of the three sites vetch reduced soybean seed yield, possibly due to a negative effect on nodulation and biological nitrogen fixation, which should be tested in future works.

Palavras-chave : Oat; vetch; sulfate; greenness index; yield.