Carbohydrate Composition and Water-Stable Aggregation of an Oxisol as Affected by Crop Sequence under No-Till

Autor(es)

Martins, Marcio dos Reis ^[1] ; Angers, Denis A. ^[2] ; Cora, Jose Eduardo ^[1]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ, Dep Soil Sci, BR-14884900 Jaboticabal, SP - Brazil

^[2] Agr & Agri Food Canada, Soils & Crops Res & Dev Ctr, Quebec City, PQ G1V 2J3 - Canada

• Tipo de documento: Artigo Científico
• Fonte: Soil Science Society of America Journal; v. 76, n. 2, p. 475-484, MAR 2012.
• Citações Web of Science: 19

Resumo

In no-till systems, plants play a substantial role in soil physical conditioning because physical management is otherwise confined to sowing operations. We performed a study to determine the effect of 28 different crop sequences on soil water-stable aggregation, soil organic C (SOC), and the neutral carbohydrate composition of the surface layer (0-5-cm depth) of an Oxisol under no-till. Summer crop sequences with corn (Zea mays L.) on a continuous basis or in rotation with soybean {[}Glycine max (L.) Merr.] showed a higher mean weight diameter (MWD) of water-stable aggregates than those with a rice (Oryza sativa L.)-bean (Phaseolus vulgaris L.)-cotton (Gossypium hirsutum L.) rotation. Among winter crops, pearl millet {[}Pennisetum americanum (L.) Leeke] or grain sorghum {[}Sorghum bicolor (L.) Moench] were associated with a higher MWD than oilseed radish (Raphanus sativus L. var. oleiformis Pers.). Plant tissues of Poaceae species (corn, pearl millet, and sorghum) were enriched in pentoses relative to other plant species. A principal component analysis showed a close positive relationship of the soil aggregate MWD with the soil xylose content, but not with other soil monosaccharide and SOC contents, and a positive relationship with the amount of pentose input to the soil, notably from aboveground plant materials. A possible explanation is that pentosans are used as an energy source by filamentous microorganisms, which play a well-known role in stabilizing soil aggregates. Our results suggest that plant-derived carbohydrates mediate crop species effects on soil structure under no-till conditions, and this effect appears to be independent of changes in total SOC. (AU)

• Processo FAPESP: 08/57755-5 - Efeitos de sequencias de culturas em sistema de semeadura direta sobre componentes organicos e a estabilidade de agregados do solo
• Beneficiário: Márcio dos Reis Martins
• Modalidade de apoio: Bolsas no Brasil - Doutorado