Preliminary analyses showed that biomass yield reached more
than 97% of the on-farm plateau yield on the 5th year after planting
in all soil texture classes. Therefore, the 5th year after planting was
used to estimate on-farm plateau biomass yield, YOF. This same predefined
year was also used to calculate the average actual observed
on-farm plateau of biomass yield using available yields from fields
harvested on the 5th year after planting. This average on-farm
biomass yield plateau was later used to calculate yield gaps.
Curve-based yield plateaus and biomass yield by the end of the first
year (Y0) were estimated for each soil texture category (heavy,
middle and light; H/M/L) using the Gompertz model (Equation (2)).