Could growing maize after first-cut silage, or an early grazing round, help to lift total forage production on dairy units this season? We spoke to a forage specialist to find out more.
TEXT PHIL EADES
Despite recent encouraging movements in milk prices, the opportunity to improve margins will be impacted by current and forecasted higher purchased feeds costs. So anything that can improve the total quantity and quality of forages made this summer will potentially help reduce the levels of purchased feeds required going into next winter.
“Maximising production from home-grown forage must remain a priority this season because, despite the increased cost of fertiliser, forage, whether grazed or conserved, remains the cheapest way to feed dairy cows,” says LG Seeds’ Tim Richmond. “Producers with good stocks of high-quality forage will be in a better position to formulate cost-effective rations.”
For producers who can successfully grow maize, there could be significant benefits from drilling maize as a replacement for poorer producing grass swards if the field is suitable for growing maize.
“Not all grass swards are as productive as others, and all dairy units will have some poorer yielding, worn-out fields – possibly suffering from more poaching or a higher proportion of less productive grasses.
“Ideally, these fields would be reseeded, but waiting to do this until the autumn means accepting a lower level of productivity,” says Mr Richmond.
“For units where maize is an option, and if the field is suitable, cultivating it this spring and drilling maize could offer significant benefits.”
He suggests it’s possible to take either an early grazing or a slightly earlier first cut and still grow a successful maize crop. Maize breeding programmes mean there is a good choice of early and ultra-early varieties, which can mature successfully in a shorter growing season and still produce a high yield of quality forage.
Maize drilling: opt for early or ultra-early varieties
“These varieties could all be drilled successfully in early May, which would allow a decent early first cut of grass to be taken beforehand,” he explains. “Alternatively, the field could have been heavily grazed, helping develop a grass wedge on the rest of the grazing block, and potentially helping protect other grazing paddocks from poaching.
“Although we saw late-drilled crops perform well in 2021, and catch up with earlier drilled crops, it is vital to make sure a suitable maize variety is drilled. And be realistic about the field and whether it is suitable for maize, avoiding those with compaction or waterlogging issues.”
Mr Richmond says the benefits of replacing a less-productive grass sward for one season with maize can be significant. Data from Trouw Nutrition Grasswatch show that, during the past six years, grassland has averaged 7,000kgDM/ha from late May until the end of the season. “During the same period, a late-drilled maize crop can be expected to yield at least 13 tonnes of dry matter per hectare with many varieties producing more than 15 tonnes of dry matter. So maize could double dry-matter production.
“Then there is quality,” adds Mr Richmond. “Typically, second-cut grass silage will be around 10.7MJ/kgDM while third cut will be 10.5MJ/kgDM. And there can be considerable variation. Maize is a more consistent forage and typically averages 11.5MJ/kgDM.
“This adds up to a significantly higher potential production from forage. Even taking a modest yield of 13tDM/ha for maize, the higher dry matter yield and energy content compared to second- and third-cut grass silages adds up to an extra 14,000 litres per hectare from forage. This is equivalent to a saving of 6.3 tonnes of concentrate per hectare of maize.”
Knowing that more forage has been secured for the winter, it might be possible to then also reduce the quantity of third-cut silage and release more grassland for mid- and late-season grazing.
“Maize is also less expensive to grow than grass,” Mr Richmond. “Maize requires 120kgN/ha compared to 250kgN/ha for a three-cut grass silage system.”
Data from the Maize Growers Association shows grass silage costs £83/tDM to grow, excluding rent, while on the same basis a 13tDM/ha crop of maize costs £73/tDM. This drops to £54/tDM if the yield increases to 17tDM/ha.
“Maize can also save on purchased fertiliser costs as much of the nitrogen requirement can be supplied from slurry as opposed to bagged fertiliser,” Mr Richmond says.
Assuming maize is harvested in good time, there will also still be time to establish a new grass ley ready for the following year. Alternatively, in more marginal areas, a catch crop of forage rye or Westerwolds would be a good option, with the land put back into grass or maize again in the spring.
Mr Richmond stresses this approach will not be suitable for every situation. The farm and field must be suitable for growing maize, and then attention to detail must be paid to variety selection and establishment.
“Producers must choose an early variety. Look for one with an FAO less than 170, combined with good early vigour and feed quality. Varieties including Gema, Prospect and Trooper would all fit the bill, helping ensure a crop with yields comparable to later maturing varieties, but which are ready to harvest sooner, and allowing the successor crop to be established.”
Prepare the seed bed well and ensure soil temperatures of between 8˚C and 10˚C at drilling depth, to ensure a rapid germination. As maize sown after grass can be at increased risk of wireworm and leatherjackets, also use a seed treatment such as Starcover Force.
“For units where maize can be grown successfully, taking a hard look at quality of grassland and replacing poorer quality swards with a crop of maize, could help get the best return from fertiliser by boosting overall forage productivity. And it will also help to insulate businesses from higher feed costs next winter,” adds Mr Richmond. “It’s certainly worth taking a closer look at the options.”