Late-sown maize experiment set to lift forage stocks
By Richard Allison
UNCONVINCED by the benefits of third cut grass silage, one producer has sown a maize crop following second cut ryegrass silage in June.
Experimenting with a 5ha (13 acre) field at Hurlands Farm, Petworth, West Sussex, John Hancock believes it will increase forage production for his 180-cow herd, which averages 7800 litres.
"Third cut silage is normally a struggle on our light greensand soil with the sward consisting mainly of seed heads and there never seems to be enough winter forage to maintain the high stocking rate."
The maize was sown in June – six weeks later than normal – following two silage cuts of ryegrass. Total ryegrass yields were 46t/ha (18.6t/acre), with first cut taken on May 7 and second cut on June 20.
The experimental maize crop is expected to yield 29t/ha (11.7t/acre) when harvested at the same time as the main crop in late October. "I prefer to harvest maize later, at a higher dry matter, because that allows sufficient time for the following winter wheat to establish without any yield penalty," says Mr Hancock.
Maize plants have grown to nearly 2.4m (8ft) in eight weeks and are now partitioning energy into the cobs. They will continue to swell over the next few weeks as the crop matures, he adds.
The crop was established after spraying off grass with glyphosate and ploughing it in. The seed-bed received a 12:15:20 NPK product and mono-ammonium phosphate applied through the seed drill.
"All fertilisers used on the farm also contain sulphur. However, no slurry was applied before drilling maize because the field is too far from the farm."
Producers considering sowing maize in June must have irrigation available, says Mr Hancock. "Irrigation is often needed to ensure adequate moisture for germination. The crop at Hurlands Farm is on greensand, which usually has insufficient moisture for germination in late June."
To ensure a reasonable yield, an early maturing maize variety is required, says seed supplier Grainseeds Neil Groom. "Although there are several early maturing varieties available which are designed for growing in marginal maize areas, Mr Hancock also wanted a reasonable starch content when harvested at the same time as the other crop in late October to save on contractor costs.
"The variety Nancis met all these demands due to its high cob ripeness and starch potential."
There will be a penalty on dry matter yield and starch content from the shorter growing season, but the forage is still a bonus, says Mr Hancock. "Even with a lower starch content, it is a useful high quality forage for bullocks, dry cows or heifers."
Another advantage of late maize is less reliance on weather at harvesting – all it takes is a wet day to reduce third cut silage quality. Maize silage is also more consistent with a metabolisable energy content between 10.5 and 11MJ/kg DM.
"Maize silage is fed to cows in a mixed forage diet including grass silage and brewers grains. This mix insures against seasonal variability in grass silage quality."
Mr Hancock believes growing a late maize crop instead of taking a third cut will be economic. Third cut yields are normally low and its harvesting costs high because contractor fees are based on area, he says.
At Hurlands Farm, maize is grown in an arable rotation with winter wheat and turnips. "There is little time when the land is bare, so the risk of soil wash is reduced and cropping maximised."
Turnip catch crops are also an essential part of Mr Hancocks winter feeding strategy. They are direct drilled following winter wheat and, like late maize, need to be irrigated to ensure good germination.
Turnips typically yield 10-15t/acre, but there is no point growing the crop unless it is grown well and justifies time spent each day moving the electric fence.
"The farm has a long history of double cropping because the light soil warms up rapidly in spring so extending the growing season. Now we are achieving triple cropping." *
• Irrigation essential.
• Early maturing variety.
• Increase forage production.