Myerscough College near Preston in Lancashire has hosted an openday in conjunction with agronomy company Agrovista, showcasing their trial of maizeunder plastic versus open-sown maize. There were 22 varieties in the trial, andamongst those showing good early vigour and the ability to quickly breakthrough the plastic was variety Ambition from seed breeder Limagrain.
The trial aims to provide a true indication of the differencesbetween open-sown maize and maize grown under plastic. All plots were drilledon the same first available sowing date, 24th April.
Agronomist Nigel Walley from Agrovista explained: There are onlya limited number of varieties which we would recommend for growing underplastic. Certain varieties tend to creep along the ground and are unable topenetrate through the film. Others show severe stress after breaking throughthe plastic, negating the advantage it offers.
The trial is designed to assess the cost benefits of thedifferent systems and the performance of the different varieties. Each varietyis scored on its ability to penetrate through the plastic with minimum stress.
Mr Walley said: Limagrain variety Ambition broke through theplastic very quickly and demonstrated good early vigour. Another which showspotential is new variety Emblem, it was included in the trials for the firsttime this year and is due on next years NIAB List.
The trials have also incorporated maize undersown with both hybridryegrasses and vetches to provide a forage crop overwintering option. The maizewas undersown with the grass mixture once it had reached the eight leaf stage.In addition, undersowing also helps reduce soil erosion and significantlyreduces the risk of nitrate run-off.
Different herbicide programmes were also trialled to establishwhich will control weeds in the maize crop without killing the ryegrass orvetch. Mr Walley explained: The results were promising, having another foragecrop available after the maize, along with the environmental benefits of theundersowing, is a definite benefit and there will be further trials.
Mr Walley added: Although both plots were harvested on the 9thOctober, the maize under plastic should have been harvested a fortnightearlier. The early varieties under plastic were well past their optimum harvestdate. Quality results are not back yet, but the dry matter of the plant isestimated at well over 30%, with starch levels approaching 40%.
From previous trials we know that maize under plastic will havehigher starch and dry matter yields than the same variety grown conventionally.In the open-sown plots weve seen mature cobs on plants which are still green,resulting in lower than expected dry matters, particularly with mid maturityvarieties. Its the same with most commercial crops, especially those harvestedin early October.
Plastic film is often used as a management tool to bring cropmaturity forward to allow early wheat drilling. But although there are extracosts in growing maize under plastic, for some growers it is a necessity,especially in marginal areas. Choosing the right variety is paramount, only byconducting extensive trials do we find what performs well and what doesnt.
The correct choice of plastic film is also essential. Agrovistaonly advocates the use of Samco System film, however they have several gradesavailable, some of which show significant advantages over others.