National and regional maize grain and silage strip trial yields

Abstract

Maize (Zea mays) grain yield in New Zealand has increased linearly, on average by 104 kg/ha/year (R2=0.51) while maize silage yield has increased linearly on average by 166 kg DM/ha/year (R2=0.47), based on strip trial data (1991-2015 for grain, and 1996-2015 for silage). Over the same periods, grain yields (based on 14% moisture content) have increased on average in the lower North Island (LNI) by 175 kg/ha/year (R2=0.45) while average silage yields have increased in the Waikato by 212 kg DM/ha/year (R2=0.48), in the LNI by 177 kg DM/ha/year (R2=0.31) and the South Island by 155 kg DM/ha/year (R2=0.30). Annual variations in yield can be attributed to changes in trial locations and trial co-operators over time. However, overall trends towards increasing yield are due to improvements in hybrid genetics, maize agronomy and management practises. Growing and harvesting costs for producing maize silage on an average soil fertility property in the Waikato have increased 3 c/kg DM over 13 years. Keywords: maize silage, maize grain, Zea mays, corn, yield