Pore size distribution in soils irrigated with sodic water and wastewater

Abstract

Soil porosity, especially pore size distribution, is an important controlling factor for soil infiltration, hydraulic conductivity, and water retention. This study aimed to verify the effect of secondary-treated domestic wastewater (STW) on the porosity of a sandy loam Oxisol in the city of Lins, state of São Paulo, Brazil. The two-year experiment was divided into three plots: soil cultivated with corn and sunflower and irrigated with STW, soil cultivated and irrigated with sodic groundwater, and non-irrigated and non-cultivated soil (control). At the end of the experiment, undisturbed core samples were sampled from 0 to 2.0 m (8 depths). The water retention curves were obtained by tension plates and Richard's pressure plate apparatus, and the pore size distribution inferred from the retention curves. It was found that irrigation with treated wastewater and treated groundwater led to a decrease in microporosity (V MI), defined as the pore class ranging from 0.2 to 50 μm diameter. On the other hand, a significant increase in cryptoporosity (V CRI) (< 0.2 μm) was identified throughout the soil profile. The presence of Na+ in both waters confirmed the role of this ion on pore size distribution and soil moisture (higher water retention).

Modification of sandy soil hydrophysical environment through bagasse additive under laboratory experiment

“…When the contact angle equals zero, the pore diameters corresponding to pressure 0.1, 0.33 and 15 bars are equal to 28.8, 8.6 and 0.19 µm, respectively. Pores with diameter >28.8 µm were classified as rapid drainable pores (RDP) or 'macropores', pores with diameters of 28.8-0.19 µm as water holding pores (WHP), and pore with diameter <0.19 µm as fine capillary pores (FCP) or 'micropores' (Gonçalves et al, 2010).…”

The changes in the physical and hydraulic properties of a loamy soil under irrigation with simpler-reclaimed wastewaters

“…Water retention, infiltration and hydraulic conductivity are among the soil hydraulic properties affected by soil porosity and pore size distribution (Gonç alves et al, 2010;Wang et al, 2003). Mojid and Wyseure (2013) determined enhanced saturated hydraulic conductivity and water retention capacity values in the wastewater irrigation conditions compared to freshwater irrigation.…”

Modeling of Saturated Hydraulic Conductivity and Mean Soil Pore Diameter in an Alluvial Loamy Soil

“…(Abdel-Monem et al 2009). In addition, Gonçalves et al 2010. illustrated that the irrigation with treated wastewater (sodic waters) modifies the soil pore size distribution and pore mean diameter by slightly increasing macroporosity (pore diameter higher than 50 μm) and decreasing microporosity (0.2-50 μm).…”