Tillage systems significantly affected dry matter production in
2006, 2007 and 2008, but not in 2009, the wettest year (Fig. 3). N
fertilization significantly increased dry matter production at several
growth stages in 2006, 2007 and 2009, but not in 2008, the driest
year. In 2008, the interaction between N fertilization and tillage
system was significant at various growth stages. N fertilization
usually increased crop growth under NT, by an average of 50% on ZN,
while it did not lead to any response under CT.