lfr: Land Fertility Regeneration
Variable
Agricultural sector
Land Fertility Regeneration [Veg eq kg/(year*year*hectare)]
lfr = ( ilf - lfert )/ lfrt

lfr in the updating graph: ( how to read )
In nodes
ilf : inherent land fertility
lfrt : land fertility regeneration time
lfert : Land Fertility
Out nodes
lfert : Land Fertility