Soil organic carbon in cropping sequences with predominance of soya bean in the argentinean humid Pampas

MARTINEZ, JUAN P.; CRESPO, CECILIA; SAINZ ROZAS, HERNÁN; ECHEVERRÍA, HERNÁN; STUDDERT, GUILLERMO; MARTINEZ, FERNADO; CORDONE, GRACIELA; BARBIERI, PABLO

SOIL USE AND MANAGEMENT

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 36 p. 173 - 183

0266-0032

Soya bean (Glycine max (L.) Merr.) monoculture can lead to a decrease in labile fractionsof soil organic carbon (SOC). This study sought to evaluate the effects of covercrops (CC), application of fertilizer, and crop rotation on SOC, particulate organiccarbon (POC), and soil carbon input in soya bean-based crop sequences under a no-tillcropping system in the Argentinean Humid Pampas. Five crop sequences at twosites differing in initial SOC were evaluated: continuous soya bean (Sb), continuoussoya bean fertilized with phosphorus (P) and sulphur (S) (Sbf), grass CC / PS-fertilizedsoya bean (CC/Sbf), nitrogen (N)-fertilized CC / PS-fertilized soya bean (CCf/Sbf) and NPS-fertilized crop rotation with high intensification sequence index (ISI) (Rot). At 0?5 cm, SOC and POC were higher (p < .05) in the sequences with higher residue-C supply (CC/Sbf; CCf/Sbf and Rot) at both sites. Changes in SOC at 0?20 cm simulated by AMG model closely tracked measured results at 0?20 cm.Findings from this study suggest that the inclusion of CC or crop rotation with highISI improved C balance in soils under crop sequences with soya bean predominance.