This report discusses the effects of maize establishment methods on established plant populations, maize yields, and associated gross margins. It is based on the findings of 38 FAR maize tillage and establishment trials between 2005 and 2020. This report discusses the effects of maize establishment methods on established plant populations, maize yields, and associated gross margins. It is based on the findings of 38 FAR maize tillage and establishment trials between 2005 and 2020.
A meta-analysis of 38 FAR trials investigating different tillage establishment methods for maize production was carried out by Plant & Food Research (PFR). The main findings included:
A yield advantage to using full cultivation establishment practices was observed. Median grain yield was approximately 5% higher, or 0.5 t/ha for full cultivation (FC) compared to the no tillage (NT) treatment, while 25 % of the trials had a FC yield advantage >10%. It is, however, not possible to comment upon whether best practice tillage was conducted in these trials.
When a subset of the data was used to include only sites with a seeding rate of 88–90 thousand seeds per hectare, the established plant population was consistently lower for the NT tillage (median 85 000 seeds/ha) than strip tillage (ST) and FC treatments (medians 90 and 88 000 seeds/ha). Established plant population is often considered to be more variable under NT than FC, but we did not observe it to be more variable, just lower overall.
While there are insufficient data to compare results robustly, there is no indication of yield advantage or penalty associated with nitrogen (N) fertiliser rate, or of an N interaction with tillage treatment. We observed for two silage trials where zero fertiliser N was applied, yields of ~18 and 27 t DM/ha were recorded. As no soil mineral N information was available, we cannot comment on whether this trend is observed due to ample soil and fertiliser N in the growing system, resulting in yields being limited by factors other than N or otherwise.
Using a slightly modified overall dataset to investigate financial aspects, we found that the economic advantage tended to favour NT. This was largely assumed to be associated with taking into account the cost of additional cultivation passes for FC and was noted despite our previous observation of a small yield advantage to FC.