Influence of Crust Formation on Soil Porosity under Tillage Systems and Simulated Rainfall

Jaqueline Dalla Rosa (1) , Miguel Cooper (2, 3) , Frédéric Darboux (4) , João Carlos Medeiros (1) , Carla Campanaro (2, 3) , Luiz Roberto Martins Pinto (5)

1 Campus Professora Cinobelina Elvas
2 Departamento de Ciência do solo
3 USP - Universidade de São Paulo = University of São Paulo
4 URSols - Unité de Science du Sol (Orléans)
5 Campus Soane Nazaré de Andrade

Surface crusts, formed by raindrop impact, degrade the soil surface structure causing changes in porosity. An experiment was conducted with the objective of evaluating the influence of the formation of a crusting layer on the porosity (percentage of area, shape and size) of a Haplic Acrisol under three tillage systems, and simulated rainfall. The tillage systems were: conventional tillage (CT), reduced tillage (RT) and no-tillage (NT). Each tillage system was submitted to different levels of simulated rainfall (0, 27, 54 and 80 mm) at an intensity of 80 mm·h−1. Undisturbed soil samples were collected and resin impregnated for image analysis in two layers: layer 1 (0–1 cm) and layer 2 (1–2 cm). Image analysis was used to obtain the pore area percentage, pore shape and size. The degradation of the soil surface and change in porosity, caused by rainfall, occurred differently in the tillage systems. In the CT and RT systems, the most pronounced pore changes caused by rainfall occurred in layer 1, but in the NT system, this change occurred in layer 2. The rainfall caused change of pore area percentage in the CT and RT systems, with reduction of complex and an increase of rounded pores. The NT system showed greater occurrence of the rounded pores (vesicles), originated by processes of wetting below the residue cover, and by alternating periods of wetting and drying. In this study, the changes in porosity were attributed to two main factors: (1) to the effect of the raindrop directly on the soil surface (for CT and RT tillage systems) and (2) water transfer processes in the soil surface (for NT systems).

Mots clés: image analysis; pore shape; pore size; soil crusting; soil structure; rain simulator

Mots clés: analyse d'images; structure du sol; diamètre des pores; travail du sol; simulateur de pluie; modèle de formation de croûte; taille des pores; croute de sol; porosité du sol; croute; formation des sols

Domaines: Environnement et Société; Sciences de la Terre; Modélisation et simulation

Jaqueline Dalla Rosa, Miguel Cooper, Frédéric Darboux, João Carlos Medeiros, Carla Campanaro, et al.. Influence of Crust Formation on Soil Porosity under Tillage Systems and Simulated Rainfall. Hydrology, 2017, 4 (1), pp.1-15. ⟨10.3390/hydrology4010003⟩. ⟨hal-01594552⟩