12th September 2022

College trial compares maize under plastic with open-sown maize

Myerscough College near Preston in Lancashire has hosted an open day in conjunction with agronomy company Agrovista, showcasing their trial of maize under plastic versus open-sown maize. There were 22 varieties in the trial, and amongst those showing good early vigour and the ability to quickly break through the plastic was variety Ambition from seed breeder Limagrain. 

The trial aims to provide a true indication of the differences between open-sown maize and maize grown under plastic. All plots were drilled on the same first available sowing date, 24th April. 

Agronomist Nigel Walley from Agrovista explained: “There are only a limited number of varieties which we would recommend for growing under plastic. Certain varieties tend to creep along the ground and are unable to penetrate through the film. Others show severe stress after breaking through the plastic, negating the advantage it offers. 

“The trial is designed to assess the cost benefits of the different systems and the performance of the different varieties. Each variety is scored on its ability to penetrate through the plastic with minimum stress.” 

Mr Walley said: “Limagrain variety Ambition broke through the plastic very quickly and demonstrated good early vigour. Another which shows potential is new variety Emblem, it was included in the trials for the first time this year and is due on next year’s NIAB List.” 

The trials have also incorporated maize undersown with both hybrid ryegrasses and vetches to provide a forage crop overwintering option. The maize was undersown with the grass mixture once it had reached the eight leaf stage. In addition, undersowing also helps reduce soil erosion and significantly reduces the risk of nitrate run-off. 

Different herbicide programmes were also trialled to establish which will control weeds in the maize crop without killing the ryegrass or vetch. Mr Walley explained: “The results were promising, having another forage crop available after the maize, along with the environmental benefits of the undersowing, is a definite benefit and there will be further trials.” 

Mr Walley added: “Although both plots were harvested on the 9th October, the maize under plastic should have been harvested a fortnight earlier. The early varieties under plastic were well past their optimum harvest date. Quality results are not back yet, but the dry matter of the plant is estimated at well over 30%, with starch levels approaching 40%. 

“From previous trials we know that maize under plastic will have higher starch and dry matter yields than the same variety grown conventionally. In the open-sown plots we’ve seen mature cobs on plants which are still green, resulting in lower than expected dry matters, particularly with mid maturity varieties. It’s the same with most commercial crops, especially those harvested in early October.

 â€œPlastic film is often used as a management tool to bring crop maturity forward to allow early wheat drilling. But although there are extra costs in growing maize under plastic, for some growers it is a necessity, especially in marginal areas. Choosing the right variety is paramount, only by conducting extensive trials do we find what performs well and what doesn’t. 

“The correct choice of plastic film is also essential. Agrovista only advocates the use of Samco System film, however they have several grades available, some of which show significant advantages over others.”

For more details, growers can contact Nigel Walley at Agrovista on 07833 236515.

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