Highlights from the MGA Conference

Published 13 March 15

For those who were unable to attend the Maize Growers Association Conference in late February, Tom Goatman, DairyCo extension officer, provides an overview.

Cover crops in reducing soil and nutrient loss – Hans Spelling Oestergaard (SEGS, Denmark)

Hans Spelling discussed the experience of Danish environmental legislation implementation, and the strategies being investigated for growing cover crops in maize to reduce nitrogen leaching over autumn and winter.  His work has involved screening 18 different cover crops and assessing the suitability for growing in maize, utilising different sowing techniques and times and on different soil types.  He identified two critical aspects to cover crop selection:

  1. The cover crop must germinate before the maize closes the rows.
  2. The cover crop must not be so vigorous that it interferes with the maize.

The work conducted in Denmark has concluded that cover crops sown at the same time as maize reduce the yield significantly on soils with low fertility (pre-crop grain or maize), but not on soils with high fertility (pre-crop grass with clover).  The most effective method of sowing the cover crop in maize was to strip sow in 3 rows (20cm from the maize plants) at a precise depth of 1-2cm. In terms of choice, slow growing species such as tall fescue were identified for early sowing with fast growing species such as perennial ryegrass identified for later sowing.

New insect pests of Maize: The European Corn Borer and the Western Corn Rootworm – James Bell, Rothamstead, UK

James Bell discussed the emergence of two new insect pests to maize crops in the UK, the first being The European Corn Borer.  This is a moth and was first discovered feeding in maize in 2012 in Devon, causing serious damage to the crop.  James highlighted that there have also been reports of adults migrating or the larvae causing maize crop damage in Hampshire, Sussex and Essex and believes the true extent of the problem is likely to be considerably under-reported.   

The adult moths either first generation or second generation (if larvae have overwintered in maize stalks below ground) lay eggs on the maize.  These then hatch and the larvae bore inside the maize stem feeding on tissue and disrupting the flow of nutrients in the stem. 

James highlighted that if corn borer is suspected, cutting through and affected maize plant stem will reveal the larvae feeding inside.  Monitoring and surveillance of the pest is critical and James encouraged the reporting of any sightings of the pest to Rothamsted, the reporting page can be found at: http://www.rothamsted.ac.uk/european-corn-borer The second pest discussed was the Western Corn Rootworm.  The beetle has been recorded at a few sites in the UK but not formally since 2007.  He highlighted that, although the pest has been eradicated, growers should remain vigilant.  The larvae feed on the roots of the maize plant and the first sign of the pest being present is a characteristic ‘goose-necking’ leading to eventual lodging of the plant due to the effect on the plant’s structural stability.

According to James, both pests struggle under a rotational system and the best method of control of both of them is to avoid planting continuous maize and routinely rotate fields where possible. 

Update on New Cross Compliance Rules for Soils – Simon Draper

Simon Draper highlighted the three new Good Agriculture and Environmental Condition standards to cover soil management responsibilities:

GAEC 4 - Providing minimum soil cover

GAEC 5 - Minimising soil erosion

GAEC 6 – Maintaining the level of organic matter in soil.

Simon highlighted the importance of understand the soil protection risks associated with growing maize crops on different types of topography and soil type and to ensure that responsibilities under the GAEC’s are fulfilled.  He highlighted the use of under sowing with grass as an important management tool with a number of recommendations:

  • Use half the normal seed rate at the 6-8 leaf stage of the maize.
  • The easiest way to sow the seed is by broadcasting but it does give the most variable results. In Denmark where there is less summer rainfall specially adapted drills are used to drill in between the rows.  In the UK, cereal drills could be used up until the 6 leaf stage without too much damage to the maize crop.
  • Soil moisture at grass sowing time is important as germination will be reliant on soil moisture.
  • Generally apply herbicides as pre-emergence or early post-emergence.
  • Herbicides will have some effect on the grass germination.  The effect is not total but does cause poor germination and slow growth.  Slow growth is helpful in reducing competition with maize.
  • Where a grass crop is required after maize, avoid the use of Nicosulfuron and/or foramsulfuron+iodasulfuron.

The Cross compliance in England: soil protection standard 2015 can be found at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/397046/CCSoilPS_2015_v1_WEB.pdf

Full conference papers are available to MGA members on the Maize Growers Association website.