In the first of our 2017 Maize Matters series, we look at varietal choice and the importance of keeping on top of weed control, as well as the potential benefits of growing the crop under film.
Last year’s maize crop went on record as one of the best in recent history, in terms of both early harvest and feed quality, according to independent nutritionist, Richard Webster, who is based in the Midlands. It provided an ideal complement to grass silage, which was disappointingly high in fibre and low in energy and protein.
For first-time growers, he recommends choosing a variety which combines good initial vigour with early cob maturity and a high starch content potential, especially on farms in marginal areas.
“Early vigour is one of the most important traits in a variety, because the crop canopy will be established in time to make the most of the sunlight and long days in June and July,” says Mr Webster. “This will produce a bulk crop that is high in starch and matures to permit an early harvest.”
Agrovista’s John Ball points to the need to get on top of weed control while maize plants are young. Some 60 per cent of his Lancashire clients use a pre-emergence treatment, usually based on pendimethalin, although others have had success with a single, post-emergence application of Syngenta’s Elumis.
“A pre-em will be needed on fields where continuous maize is grown, or where competitive weeds such as annual meadow grass or fat hen are present,” says Mr Ball. “A typical application would be based on either Stomp at 2.5 litres/ha or Wing-P, at 3 litres/ha. This will sensitise the plants and increase the knock-out rate of the post-emergence spray.”
Meanwhile, a single, post-em treatment may be adequate on farms with a lower weed burden, or with longer rotations, especially they include grazed grass, he suggests. It may also be the only option, when there has been insufficient moisture in the top two centimetres of soil to activate the pre-em application. Elumis, which can be used up to the eight-leaf stage, combines mesotrione + nicosulfuron in one liquid treatment, covering a wide spectrum of weeds and with greater efficacy, compared with standard straight options, he says. Complementary adjuvants and wetting agents have been selected and particle size has been reduced, for faster uptake.
“Decisions will be based on individual farm situations and Elumis is just one of the weapons in our armoury,” says Mr Ball. “Weeds which overtake young maize plants intercept light and slow down growth rates. This produces a smaller cob with reduced starch; the very quality which growers are hoping to maximise.”
IT MAY be time to take a fresh look at growing maize under film, according to Mike Corp of Procam South West, who says modern products are much-improved.
“The new, biodegradeable films have thermic and ultraviolet degrading properties and high elasticity. Plants can break through the layer with ease and this helps to keep stress levels to a minimum. They allow the grower the flexibility of being able to sow varieties which are two to three maturity groups below the norm, as well as the security of knowing harvest will produce high yields and good ME figures.”
However, he warns that varieties for film should be chosen with care.
“The main proviso is that maize under film requires a variety which has been tested using the technique and produced good results. This is because individual varieties do not necessarily perform in the same way under film as they do when they are used in a conventional growing system,” says Mr Corp.
Agrovista’s Simon Nelson also advises careful varietal choice for growing under film and he urges growers to drill early.
“The point of using film is to protect the plant by warming the soil, thereby speeding up establishment,” he explains.
“Having invested in creating favourable conditions for the seeds to germinate in early season, it will therefore pay to make the most of the longer growing period and choosing late-maturing, high yielding varieties. This will go a long way towards achieving the ‘magic’ target figures of 28 per cent dry matter and 30 per cent starch.”
Maize-growing under film has an advantage over conventional systems, as growers do not have to delay drilling until the soil reaches the minimum temperature of 10degC and rising, for three consecutive days, adds Mr Nelson, who reports that roughly 90 per cent of his customers in Cumbria use the system.
“As long as the soil is dry enough to create a good seedbed, maize can be drilled into this greenhouse environment, until conditions are right for emergence. Good quality modern films will not break down unless there is sufficient sunshine and heat. Until that occurs, they will remain intact. Film does increase input costs, but it will produce more consistent results in marginal areas.”