The assessment of bulk density in the time is due above all to soil shrinkage-swellings and has an asymptotic trend.

The reduction of bulk density after tillage is simulated as proposed in EPIC (Williams et al., 1984):

ρ(I) is bulk density after tillage, ρ0 is bulk density before tillage and ρcis bulk density at -33 kPa (maximum). I is a tillage intensity index, that is provided by a table (Williams et al., 1984).

Larsbo and Jarvis (2003) proposed an alternative way to simulate the same process, using the minimum density after tillage:

where ρm is the minimum density after tillage.

Created with the Personal Edition of HelpNDoc: Easy EPub and documentation editor