TABLE 4.

Parameter values used in scenario simulations of the recovery of soil structure following severe compaction as a result of root production and earthworm activity

Parameter	Value
Porosity, ϕ, cm3/cm3	0.4
Minimum porosity, ϕ min, cm3/cm3	0.3
Micropore fraction of textural porosity, f t(mic)	0.8
Particle density, γ s, g/cm3	2.7
Root density, γ r, g/cm3	1.2
Fraction coarse roots, f c(r)	0.2
Root production, R g (=Br τ r), g cm−3 year−1	0.0012; 0.00012 a
Bioturbation rate, τ s, year−1	0.12; 0.012
Fraction of micropores in casts, f casts(mic)	0.8
Cast void ratio, ε casts	0.6

^aEquivalent to 30% of an above‐ground biomass production of 10 and 1 t ha⁻¹ year⁻¹ for an annual crop added to a soil layer 25 cm in thickness.