Amie Hunter, agronomist and technical support at Hutchinsons, has provided advice on successful maize establishment.
“With over 50% of the potential yield of maize dependent on good soil structure, the old saying of “well sown, half grown” has never been more appropriate than for the UK maize crop this spring,” she says.
She notes that maize does not cope well with compaction or wet feet, and that it is important to mitigate these risks where possible.
“Poor soil structure will lead to a lower maize yield regardless of variety choice, fertiliser or herbicide programmes. So it is important to start right – fields should be assessed for compaction, and if required, consider subsoiling or appropriate cultivations at the correct depth to remove the compacted layer.
“Maize seedbeds should be level and allow good seed to soil contact – but the surface should be moderately cloddy. The slightly cloddy surface allows for drainage and prevents capping, as most maize crops fail if they sit in wet, cold soils.”
When drilling later, with warm conditions, she says that a finer seedbed may be suitable. However, overworked soil can cause small, compacted layers at seed depth, and if conditions become wet, this can negatively impact rooting and yield.
“Soil temperatures should be monitored daily with at least three consecutive days of a minimum of 8oC (10oC for heavy soils) before drilling. The use of film allows soils to warm up quicker and retain warmth so drilling under film may start from lower temperatures – potentially from 60C. “
Nutrient planning
Maize can put on a considerable amount of growth in a short period of time, so the correct nutrition has to be present to support this.
“Maize is often grown in rotations with considerable organic manure use, so it is vital a suitable nutrient management plan is in place ensuring correct nutrient supply and taking account of any organic amendments.
“Despite being such a large crop, maize is a notoriously “lazy rooter” early on,” she notes. “Phosphate is vital for early root development and moves only millimetres in the soil, hence maize responds very well to starter fertiliser placed near the seed at drilling.
“Traditionally in the form of DAP there are now microgranular products such as Primary-P available offering protected phosphate applied at very low overall rates and trials have shown significant yield benefits and excellent nutrient use efficiency: applying small amounts in a targeted area.”
This should be combined with a well-planned herbicide programme, with yield losses of up to 60% possible if this is mishandled.
“Maize is very susceptible to weed competition particularly early on, so herbicide timing is absolutely key. A delay in weed control from the 2-3 leaf stage to the 4-6 leaf stage can see a 5t/ha yield difference! ,” says Amie.
“The correct use of glyphosate to start off weed free is vital, and a pre-emergence herbicide is strongly recommended. Not only does this pre-emergence herbicide reduce the early weed burden, but it also allows us to be more targeted with the post-emergence and avoid harsh tank-mixes at this post-em timing. “
Depending on target weeds, a pre-emergence based around a minimum of 1200g pendimethalin /ha is a good starting point, she advises. “Post-emergence herbicides should be targeted and adjusted according to weed spectrum but completed by the 4-leaf stage of the maize to minimise the impact on yield.”