Using Tension Disc Infiltrometer to Determine Infiltration and Water-Conducting Macroporosity and Mesoporosity Relationships in an Agricultural Silty Loam Soil

摘要

Measurement of soil hydraulic properties, such as hydraulic conductivity (K) and quantification of water-conducting macroporosity and mesoporosity (circle minus(ma), and circle minus(me)), is important to improve the understanding of soil physical behavior. The aim of this study was to assess the effects of soil loosening on circle minus(ma) and circle minus(me), as well as on K, and to relate the importance of circle minus(ma) and circle minus(me) 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 circle minus(ma), circle minus(me), and K at different water potentials (K-6, K-3, and K-0, 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).circle minus(ma) and circle minus(me) were statistically greater for CnT. Soil loosening created water-conducting macroporosity and mesoporosity that remained active after harvest.Saturated hydraulic conductivity, K-0, was mainly influenced by circle minus ma for both treatments. The influence of circle minus ma on K-0 was greater for CnT. This result indicates that the increment in K-0 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.