Pore system configuration and hydraulic properties. Temporal variation during the crop cycle in different soil types of Argentinean Pampas Region

Soil hydraulic properties and pore system configuration are important parameters to understand soil physical behavior under different tillage systems. However, there are some contradictory results, including the influence of soil type on the temporal variation of these properties during the crop cycle. The aim of this work was to determine soil hydraulic properties and soil pore system configuration in different sampling dates during the crop cycle under no tillage (NT) and conventional tillage (CT) in three representative soil types from Argentinean Pampas Region. Soil hydraulic conductivity at different tensions, pore size distribution (PoSD), water-conducting porosity and soil pore connectivity were determined in a loam Abruptic Argiudoll (Chascomds site, CHA); a silty loam Typic Argiudoll, (Pergamino site, PER); a sandy loam Entic Haplustoll (Dorila site, DOR), under NT and CT. Temporal trends of soil hydraulic properties were different in each site, depending on the tillage system. PoSD and hydraulic properties showed more pronounced temporal changes in CHA and PER as compared with DOR. Mean values of K-0 ranged between 0.47 and 3.85 cm h(-1), corresponding to PER, under NT, and CHA, under CT, respectively. CT treatment presented higher values of hydraulic conductivity and water-conducting macro porosity, especially between spring and summer, related to higher biological activity, except in PER. It was observed that tillage can increase temporally the values of total macroporosity, while the biological activity during the growing period increases the connectivity of soil macropores, improving water transport.