Be flexible with late-drilled maize crops
14 April 2009 | Mark Britton
Drilling forage maize in late April and early May doesn’t have to be restricted to varieties in NIAB maturity class 10 or 11.
Growers should not get hung-up on optimum drilling dates and maturity class (MC) if the crop still has to be sown. Instead, consider the impact of soil temperature, crop location and a flexible harvest date. This could mean potentially high yielding sites are not compromised by drilling lower-yielding, but very early-maturing varieties.
“The traditional optimum target drilling date for forage maize has always been 20th April,” says Nigel Padbury, technical, sales and marketing manager for NK, the Syngenta Seeds brand for maize in the UK. “With some high-daytime temperatures in March some growers could have felt pressured into drilling early in an attempt to offset any potential harvest delays following the difficulties of the past few years.”
However, even after a few days of warm sunshine seedbeds can still be cold and wet. This will only encourage soil and seed-borne diseases and affect plant counts and establishment. Nigel advises growers that it is only safe to drill when soil temperatures reach a consistent 5oC to 7oC and there is little or no risk of severe frost.
So, which varieties can be drilled after 20th April? Screening varieties by maturity class remains the major deciding factor. For those aiming for a September harvest the accepted choice are varieties with a MC 10 or 11 rating, including Camelot, Scimitar and Avenir - which after 11 years on the Descriptive List is the benchmark for earliness.
But if growers can be flexible with the final harvest date and dry matter content then later maturing, higher yielding varieties are a real possibility. This can be confirmed using NK’s easy-to-use, online variety selector at www.nk.com/uk which takes less than five minutes from start to finish. The selector is based on matching a variety’s maturity rating to the environment it is grown in and takes just five easy steps. Simply click on a target dry matter percentage; target harvest date; drilling date; field altitude; and the county in which you farm. The selector then calculates the most suitable maturity class to aim for and suggests varieties within the maturity class.
“A variety with a MC 10, for example Avenir, is recommended for a farm in Cheshire below 60 metres altitude, drilling in the second week of May and aiming to harvest at 32% DM in the first week of October,” says Nigel. “But by reducing the DM to 28% and delaying harvest for a week the farmer could drill a significantly higher yielding MC 6 variety, for example Paddy or NK Bull.
If the altitude is then increased above 60 metres the grower is advised to go back to an earlier maturing variety that needs fewer accumulated heat units. It’s about finding that compromise between yield, quality and maturity.”
Later-drilled varieties could also benefit from a seed treatment advises Syngenta’s seed treatment product manager Will Holmes. The seed treatment Maxim XL (fludioxonil and mefenoxam) has just achieved UK approval. Already used across two-thirds of the UK maize area, until now it has only been used on imported seed. Will suggests that this twin-acting fungicide mix is a major step forward from older treatments such as thiram.
“While more of a problem with early drilled stands, seedling-blight diseases are becoming more prevalent in the UK as the maize area increases. Every opportunity to reduce plant losses and improve growth in later-sown crops could also make a difference and it can help to reduce lodging risk later on in the season,” says Will Holmes.
