Aggregate distribution, stability and release of water dispersible clay for two subtropical Oxisols

Scientia Agricola

Antonio Carlos De Azevedo¹  Darrel Gene Schulze² 

[1] ,UFSM Depto. de Solos Santa Maria RS ,Brasil

关键词: land use;    disaggregation;    soil tillage;    soil management;    uso da terra;    desagregação;    preparo do solo;    manejo do solo;   

DOI  :  10.1590/S0103-90162007000100006

来源: SciELO

【 摘 要 】

The behavior of a soil regarding the dispersion and aggregation of its particles is very important for the development of environmental and agricultural soil functions. This study was conducted to determine how aggregate distribution and stability are impacted by land uses and how the release of Water Dispersible Clay (WDC) relates to disaggregation in Oxisols from subtropical Brazil. Samples from two Oxisols, collected at three depths from sites under no-tillage (NT), conventional tillage (CT) and native vegetation (NV) land uses were shaken in 250 mL plastic bottles for intervals up to 27 hours. The mass of aggregates was measured in five size classes ranging from 53 to 2000 µm. Most aggregates larger than 500 mm disappeared during the first 7.5 hours of shaking, concurrent with an increase in WDC release and without change in soil suspension pH and electrical conductivity, without increase in smaller aggregates. Therefore, there is no aggregate hierarchy in these soils and the release of WDC was caused by breaking aggregates within the 500 to 2000 mm range. Land uses affect mass of aggregates in each size class, but the aggregate stability depends on its size, not land use.

【 授权许可】

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