Resumo

CICORE, Pablo; SAINZ ROZAS, Hernán; ECHEVERRIA, Hernán  e  BARBIERI, Pablo. Nodular dry matter and accumulated nitrogen in soybean as a function of water and sulfur availability and tillage system. Cienc. suelo [online]. 2005, vol.23, n.2, pp.205-210. ISSN 1850-2067.

Nodular dry matter (NDM) and accumulated nitrogen (AN) in a soybean crop were evaluated as a function of tillage system [no-tillage (NT) and conventional tillage(CT)] and sulfur (S) availability in two experiments carried out under irrigation (Ri) and rainfed conditions (Se). The experiment was carried out at Balcarce in the 2002-2003 growing season. The NDM, determined at R5 stage, was not affected by S fertilization (P>0.10) but was higher under NT in Se (P< 0.05). Under Ri NDM was higher under NT but this difference was not significant. The AN was not affected by S fertilization, and under rainfed conditions, it was significantly lower (P<0.05) under CT. The AN was positively related with NDM but the r² value was low (36%), suggesting that NDM was not the only factor regulating biological N₂-fixation.

Palavras-chave : Soybean; Biological N₂-fixation; Nodulation; Tillage system; Water; Sulfur.

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