Measurement of soil hydraulic properties, such as hydraulic conductivity (K) and quantification of water-conducting macroporosity and mesoporosity (θma, and θme), is important to improve the understanding of soil physical behavior. The aim of this study was to assess the effects of soil loosening on θma and θme, as well as on K, and to relate the importance of θma and θme to infiltration. The experimental design was completely randomized, with two treatments: (i) no tillage and (ii) conservation tillage (CnT). The soil was classified as a Typic Argiudoll, with a silty loam A horizon. A tension disc infiltrometer at three ascending soil-water pressure heads (−6 cm, −3 cm, and 0) was used to infer θma, θme, and K at different water potentials (K6, K3, and K0, respectively), after harvest.
The K values obtained for each tension were statistically greater for CnT than for no tillage. To summarize, mean values of K varied between 0.50 and 2.06 cm h−1.
θma and θme were statistically greater for CnT. Soil loosening created water-conducting macroporosity and mesoporosity that remained active after harvest.
Saturated hydraulic conductivity, K0, was mainly influenced by θma for both treatments. The influence of θma on K0 was greater for CnT. This result indicates that the increment in K0 by soil loosening is mainly due to the creation of water-conducting macropores, supporting the idea that studies of effect of tillage on water movement should focus on macroporosity.
1Facultad de Ciencias Agrarias y Forestales, UNLP. Calles 60 y 119, CC 31. 1900 La Plata, Argentina. Dr. C. Germán Soracco is corresponding author. E-mail: firstname.lastname@example.org
2Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
Received August 31, 2010.
Accepted for publication May 20, 2011.
Financial Disclosures/Conflicts of Interest: None reported.