Work at Crichton Royal Farm is showing it is possible to get a perfectly good crop of maize after taking a cut of silage earlier in the year.

Choosing ultra early varieties and biodegradable film to aid establishment can allow milk producers to take a cut of silage and get a fully mature maize crop later in the year, new results from Dumfries’s Crichton Royal Farm are suggesting.

Not only can the approach boost overall forage production, but it also has significant environmental benefits, believes the unit’s manager, Hugh McClymont. “One of the most important aspects of moving to more sustainable production in the future is the concept of getting more from the resources we have, so taking two crops from the same piece of land in the same year has obvious advantages,” he said.

“But if we can do this while adding additional environmental benefits such as using less inputs, reducing damage to the land and getting more reliable crop production then that is technology we should really all be considering.

“Over the last few years, we’ve conducted many trials into how maize starch-based film can help producers in marginal areas get crops of maize that finish properly and produce good yields, but it’s increasingly apparent the benefits can be far greater than this.”

Maize forage is a key constituent of rations for the six different recorded groups of cows that make up the 450-strong herd currently milked at Crichton Royal, he explained. “All lactating cows receive maize silage as a proportion of their diet but what this is depends on the group and whether we’re feeding high energy or low energy rations.

“Being a research farm, our set up is complex, but our high genetic merit cows will be producing 12,500kg/cow per year with about 950kg/cow per year of milk solids whilst the lower-end genetic cows are doing more like 8800kg, with 600kg of milk solids. The forage base for all rations is pretty much the same with around 4-5kg DM/cow per day of maize silage, 8-10kg DM/cow/day of grass silage and 3kg DM/cow day of wholecrop wheat.

“Whereas the high yielders’ high energy ration will be based on 40% forage and 60% concentrates, the lower energy ration is the other way around at 40% concentrates and 60% forage, so the higher yielders are getting a lot more concentrate.”

All cows receive these rations as a full TMR, fed to stimulate rumen function and make best use of all the available forages, Mr McClymont explained. “Maize is a very high energy feed and can be more reliable than grass. If the weather is with us up here, we can make grass silage at around 30% DM, but in many years it can also be more like 20% DM.

“The beauty of maize is that if you grow it properly with the varieties and technology now available, it is usually at the top end of that at 30-35%DM because you can leave it maturing in the field until it is ready to harvest.

“That is where the combination film and variety is critical. Getting that right is essential not just so you achieve good establishment but also so the maize will mature early enough to harvest safely and give you enough time to get another crop in behind it.”

Such thinking led Hugh to consider last year whether it would be possible to take a cut of silage, get his maize in and harvested, then get a crop of winter wheat drilled.

“Crichton Royal farm sits on 300ha of grassland and we usually have around 40ha of maize. Last year, some of that early drilled into stubble left over winter and the rest went into land where we out-wintered dairy heifers on brassicas and big bale silage. The land we wanted to try for the late drilling was that used for ScotGrass 2019 which took place on May 15.

“As soon as the event was over, we took a cut of silage, applied slurry, ploughed it in then power harrowed the land and the maize was drilled. The ultra early variety Picker was chosen because of it’s known ability to mature fully with a reduced number of heat units.

“It was hoped this combined with the film would make up for the time we had lost waiting for ScotGrass to finish. The crop was drilled at 100,000 seeds/ha under Samco ‘White’ film and within 10 days it had germinated and was visible above the ground. Three weeks later, it was bursting through the film and was away.

“It was then harvested in the first week of October yielding 40-50t/ha at 32% DM and was a good mature crop, which has fed really well. The field it came from was back in wheat straight away – so all in all, it’s had three crops in the same year,” he said.

The results prove the advantages the film had in terms of producing a good crop of high energy maize when otherwise this might not be possible, but the benefits don’t stop there, Hugh believed. “Because we’re drilling into an old grass sward, there would obviously be nutrients released as that decomposed, but there was also a lot of manure applied before hand. All of these processes would be speeded up by the warmer temperatures created under the film.

“These warmer conditions would also help increase mineralisation of soil Nitrogen with all of these factors leading to better nutrient utilisation efficiency and less need for additional fertiliser.

“Last year, we applied ‘Efficie-N-t 28’ foliar nitrogen when the plants were 0.75m high to give them a bit of a boost, but apart from that no additional nutrition was required. A little bit of pre-emergence herbicide is used at drilling under the film, but because the maize plants grow so quickly, they easily out-compete any weeds so savings in herbicides can be considerable too. The withdrawal of Mesurol won’t affect us as much as others either, as the film gives a lot of protection against birds.”

Early harvest and lack of potential damage to soil in wetter conditions is also an advantage of the film, added Mr McClymont. “The quicker the crop reaches maturity, the sooner you can get in and harvest, so you’re reducing the risk of having to go in later when ground conditions can be much wetter.

“This not only reduces damage to soil structure, it also helps reduce soil erosion as you can get another crop in so land is not left bare over the winter. We’ve harvested Picker in September, but we’ve had really good results with varieties like Marco and Cathy under the film too.”

“Plus, once it’s done its job, it just degrades naturally in the sunlight. By the time we’re ploughing, we never see a trace of it,” he said.