Growing Maize Under Film in a Tough Environment – Forager Magazine – Jim Clark

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Maize Demo Day Jim ClarkFast establishing, early maturing maize varieties are essential for growers in high rainfall areas who want to avoid the environmental risks of a late harvest.

In areas of high rainfall, combining an early maturing maize variety with growing under film is a sure-fire way to maximise yields and get the crop off early before the risk of wet weather.

Failure to get the crop off before rain sets in can lead to those all too familiar wet, muddy conditions, which can create multiple environmental issues including soil erosion, compaction and nitrogen leaching into water courses.

With this in mind, Jim Clark, Cumbria-based agronomist for Hutchinsons, believes growing maize under film is well worth considering in challenging maize growing regions where variable heat units from sunlight and high rainfall can be a problem. The film will promote early maturity and early harvest along with that all important balance of quality and yield.

“In this part of the world, the ‘Holy Grail’ of maize varieties needs to deliver at least 30% starch, 30% dry matter and 6tDM/acre when harvested in late September,” explains Jim. “In order for it to be a reliable, cost-effective feed source, it must also be grown under film.”

For the last seven years, Jim has been working with dairy farmer, John Ferguson, to produce maize under film at Blencogo House Farm near Wigton. Of the 156ha (386 acres) family owned farm, 35ha (87 acres) are in maize, 32ha (79 acres) are in cereals and 89ha (220 acres) are in grazing and multi-cut silage leys. Not including cereals in the figures, homegrown forage accounts for 3,000 litres of the 11,000 litre average in the year-round calving herd of 240 commercial Holsteins.

“Land doesn’t become available for sale very often in this area, and when it does, it is very expensive. It is essential that we maximise the land resources we have available to grow as much homegrown feed as possible,” says John.

“Growing maize under film helps to ensure rapid establishment. This is essential to get the crop harvested before autumn rains set in because harvesting in wet conditions will cause significant erosion issues to our soil. Maize under film also allows us to grow a high quality, cost-effective feed with a lot of bulk to optimise land production.”

Cost of Growing Maize Under Film

Yield DM t/acre


£/t DM

Contractor costs/acre

Contractor costs/t DM

Total costs/t DM

Cost rent/t DM (£100/acre)

Cost inc. rent/t DM

























Figures provided by Jim Clark, Hutchinsons


Growing a successful maize crop

Before any maize varieties are grown on farm, they are trialled by Hutchinsons for two to three years in local research plots. This is to determine the best establishment methods and to ensure they are suitable for the regional climate.

Jim says: “While growing maize under film will add to the cost of production compared to growing it in the open, our trials and farm results have found improvements in quality and fresh weight yield will make up the difference. We want maize under film to yield at least 6tDM/acre. Including all growing, contractor and rent costs, you’re growing a high quality feed source for £77.22tDM (see chart).

“In order to be a cost-effective feed, maize must have the right growing conditions – which includes adequate heat units – otherwise the mature crop will be very inconsistent.”

Following positive trial results in 2017 that yielded 16,884tDM/ha (6.8tDM/acre), 33.6% DM, 11.6 ME and 27.7% starch content, Cardiff was selected for the 2019 planting season. This new variety from Germinal was added to the British Society of Plant Breeder’s 2020 Forage Maize Less Favourable Descriptive Lists for its ability to produce high quality silage in challenging conditions.

Thanks to a combination of variety traits and good management, the 2019 harvest at Blencogo House Farm, saw a dry weight yield of 6.2tDM/acre, 30.3% DM, 11.7ME and 32.3% starch. The crop was planted on April 10 and harvested in late September.

Targeted nutrient application has been an important factor in hitting yields and an early harvest. Prior to planting, John had fields soil tested and applied N, P, K and lime accordingly. When fields were drilled in conjunction with Samco Green Film application, 45kg N/ha was applied to the seedbed with a preemergence herbicide. To stay on top of weed competition, the maize crop was treated with a broadleaved weed and grass weed herbicide six weeks after establishment.

In the first week of July, 20 litres/ha of N Durance was applied. This is a slow release fertiliser that contributes 40kg/ha of nitrogen over the course of six weeks.

“Fertiliser application is one of the most important elements to feed the cob so it can reach early maturity for cob size and grain fill,” adds Jim.


Jim Clark’s advice for successful maize crops

  1. Test soils for efficient nutrient management.
  2. Select varieties for a balance of quality and early maturity.
  3. Apply a pre-emergence herbicide at drilling to avoid issues from weed competition.
  4. Utilise a slow release nitrogen to feed cobs for early maturity.
  5. Judge a maize crop based on cob growth, not plant height.
  6. In tough climates, grow under film for a more consistent crop.