Root induced changes of effective 1D hydraulic properties in a soil column

Area of Science:

• Soil science
• Agronomy
• Environmental science

Background:

• Roots are critical for soil structure and pore formation.
• Understanding root-induced changes in pore size distribution (PSD) is vital for soil health.
• Active root growth involves complex pore dynamics, including clogging and formation.

Purpose of the Study:

• To quantify root-induced changes in soil pore size distribution (PSD).
• To differentiate between pore clogging and pore formation during active root growth.
• To model pore evolution under the influence of plant roots.

Main Methods:

• Utilized a column experiment with mustard and rye cover crops, plus an unplanted control.
• Applied Kosugi's lognormal PSD model with inverse estimation for parameter determination.
• Employed a convection-dispersion-like model to describe pore evolution dynamics.

Main Results:

• Rooted soils exhibited wider PSD, with increased large macropores (>500 µm) and micropores (<2.5 µm).
• Fine macropores, mesopores, and larger micropores decreased in rooted treatments.
• The pore evolution model effectively captured root-induced changes, unlike soil structure degradation in the control.

Conclusions:

• Root activity leads to soil heterogenization, a dominant structure formation process.
• Pore clogging contributes to reduced pore volume, but other factors are involved.
• Root-pore interactions involve multiple mechanical and biochemical processes influencing micro- and macropores.