Switching to plastic has its advantages

Brown fields with white plastic stripes have been springing up since the end of last month – and it seems to be a more common sight this year than last.

Wynnstay says its customers are certainly growing more maize under plastic, with the massive popularity seen in South Wales for the last couple of years spreading into the West Midlands and beyond.

Mike Mustoe, senior agronomist for the company, says there has long been interest in growing grain maize under plastic and the move to growing more forage maize and ground ear maize in the same way is quite justified.

Interest from his customers has been because of the higher fresh weight yields offered from plastic and, therefore, the higher starch content.

He says larger dairy farmers growing up to 70 hectares (173 acres) of forage maize are putting 12-16 hectares (30-40 acres) under plastic in order to harvest some crop early, either to get cows settled on the winter ration sooner or reduce the risk of running out of maize silage when feeding it all-year-round.

Mr Mustoe says farmers considering plastic should do the calculations carefully and he would question the benefits if drilling cannot be done until the middle or end of May.

Clear advantage

A clear advantage is the crop matures earlier, potentially avoiding harvesting in the type of wet conditions seen last autumn.

One dairy farmer drawn by the promise of higher fresh weight yields is Ralph Fernihough of Tunstall Hall Farm, Market Drayton, Shropshire.

He owns 55 hectares (135 acres) and rents a further 42 hectares (105 acres). Each year 14 hectares (35 acres) of the rented ground is used to grow maize, and this time just under six hectares (14 acres) of that has been put under plastic.

Mr Fernihough says his neighbour put some plastic down last year and could have harvested it in August, although he took it later for grain. Impressed by that, Mr Fernihough is trying the same on a field that has produced maize ‘for quite a few years'.

Getting the crop off early will give him the option to do something different with the field afterwards, such as putting a grass ley in or wheat for wholecrop.

The field was sown on March 20, mostly with Pioneer Justina but with a couple of rows of Kokon as an experiment. Both varieties are approved for growing under plastic, as they can burst through the pinholes in the biodegradable material while some varieties cannot.

The field was prepared last autumn with an application of chicken muck just ahead of ploughing in October.

A pre-emergence herbicide was applied when the seed was drilled and the plastic lain, and a post-emergence treatment may be needed depending on the season.

The aim is to harvest at the end of August or the first week of September, around three weeks earlier than Mr Fernihough is used to and potentially five weeks earlier than his 2008 harvest.

The rest of the maize acreage will be a mix of Ixxus and Destiny, varieties that have done well at Tunstall Hall in the past. This will be planted in the third week of April and will be ensiled separately when harvested in late September.

Warm and moist soil

Mr Fernihough says he immediately saw how the plastic was keeping the soil underneath warm and moist and is looking forward to seeing how the field yields.

His maize usually does well, as the soil is light, averaging 44-49 tonnes per ha (18-20 tonnes per acre) and peaking at 62 tonnes per ha (25 tonnes per acre). He is hoping for nearer 75 tonnes per hectare (30 tonnes per acre) with the addition of plastic.

He has done his calculations and knows the crop grown under plastic will cost £742 per hectare (£300 per acre), an additional £247 (£100) compared to conventional maize.

But the benefits are more than just the yield and additional starch, he says. There is the option to plant grass or wheat afterwards, plus the fact less acreage is needed, reducing contractor fees and allowing him to rent a field adjacent to his main holding rather than one nine miles away used in previous years.

“If we can do 30 tonne to the acre then obviously we're still paying the contractor to only do 14 acres, so you've got to take that into consideration really,” he says.

“And the field is a lot closer. When we were transporting maize from nine miles away it was a considerable cost.”

Mr Fernihough says he has not ruled out growing all his maize under plastic but is treating this year as ‘trial and error'.

He feeds maize silage throughout the year to his herd of 150 commercial Holsteins, offering a ration of 60 per cent grass silage and 40 per cent maize.

The ration is kept consistent although the volume is reduced in the summer months when milk production is driven by grazed grass. Yields are averaging at 9,600 litres.

As the soil is light, Mr Fernihough says hot years present more problems than the last couple of wet summers.

The grass can ‘burn off' within a fortnight of warm weather with only 10 per cent of the diet coming from grazing in those circumstances and the rest from the ration.

Therefore, Mr Fernihough aims to get all his clamps full and prefers to have forage left over in spring rather than run short.

He uses a contractor for first cut silage, getting as much grass as possible. A large selection of owned machinery then allows him to take smaller second, third and fourth cuts as and when he wishes.

Cutting costs

In addition to a mower, rakes, silage trailers and a forage harvester, Mr Fernihough also has a muck spreader, fertiliser spreader and plough, in order to do the vast majority of machinery work himself, believing it helps cut costs. He employs one full-time member of staff.

Slurry is spread frequently, as the farm only has two weeks worth of storage and the light land can take it. However, recent changes to the NVZ regulations mean he will have to invest in a new slurry store and adhere to stricter closed period rules.

Although the land is light and cows can go out early, Mr Fernihough says the grass is not there at the moment to support them and so they are still currently housed. Bedding is sawdust on mattresses with a sprinkling of sand.

Dry cows are bedded on sand only and Mr Fernihough says this keeps mastitis very low. Dry cows are now housed in a newly adapted shed, along with the first of the heifers to be reared at Tunstall Hall.

Historically Mr Fernihough operated a flying herd but made the switch to rearing his own replacement eight months ago when prices became too restrictive.

He converted a storage shed to house dry cows and heifers and has enough smaller buildings about the place for calves. A new building has been erected for storage.

There are now 25 heifers on the unit, and although it is a long way off, Mr Fernihough is looking forward to getting them into the herd and hopefully increasing to 170 milkers, which is the capacity of his cubicle shed.

In comparison, it will be a much shorter wait to see how his maize fares under plastic.