This study analyses grain yields of soybean monitored in the variety trials performed in North-East Italy from 1983 to 2015 by
ERSA FVG in order to evaluate the existence of yield trends and how inter-annual yield oscillation could be explained either by
meteorological, genetic or agronomic factors. In this period, about 400 varieties have been tested and, despite of agricultural inputs
reduction and little change of genotypes, statistical analysis underlines an average yield increase of about 30 kg ha-1 year-1. The
regression analysis suggests that the average daily thermal excursion explains inter-annual yield variations much more than other
environmental variables (rain and soil characteristics). In conclusion, the higher yields observed in the last years seem mostly due
to both environmental conditions and improved cultivation techniques.
