Surface and incorporated liming effects on clay dispersion, water availability, and aeration capacity of a Dystrudept soil

Liming represents a management procedure that can affect the soil structure and its thermodynamic processes. In this context, the aims of this study were to assess (i) the effects of the surface and incorporated liming on the clay dispersion, soil water availability, and aeration capacity; (ii) the influence of soil chemical alterations in its physical attributes. For this, a field experiment was installed in a family farming property, located in the southeastern region of the State of Parana, in a Dystrudept soil. The treatments were 3 application modes (on the surface, incorporated via plowing and incorporated via subsoiling and harrowing), with and without 15 Mg.ha(-1) of lime, aiming to increase the base saturation in the topsoil (0 - 0.20 m) to approximately 70%. Eighteen months after application, undisturbed and disturbed soil samples were collected from the 0 - 0.10 and 0.10 - 0.20 m layers to evaluate the waterdispersed clay (WDC), water content at the field capacity (theta(FC)) and at the permanent wilting point (theta(PWP)), plant available water capacity (PAWC), relative water capacity (RWC), aeration capacity (AC), granulometry and the soil structural and chemical attributes. WDC content in the 0 - 0.10 m layer increased when the soil was revolved and it was influenced exclusively when lime was applied on the soil surface. With surface liming there were increase in. FC, theta(PWP), PAWC and RWC, and reduction in AC in the 0 - 0.10 m layer. In the 0.10 - 0.20 m layer isolated effects were verified of the modes application and liming on. FC, PAWC and RWC, while. PWP was not influenced by treatments. The soil water availability and aeration capacity alterations were mainly affected by micro and macroporosity increases, pH reduction, Al3+ precipitation, and substitution of this ion in the exchange complex by Ca2+ and Mg2+.