The second article in our KWS Maize Matters series for 2018 offers some advice on varietal choice and highlights the importance of timely drilling and good early nutrition.
High starch is a primary target for most growers of maize for dairy total mixed ration (TMR) and beef rations, says John Burgess of KWS, and plant breeders have made rapid progress on quality over the past decade. In 2008, NIAB list varieties averaged 31.4 per cent starch, while the figure for 2018 had risen to 35.1 per cent.
Mr Burgess says: “As plant breeders, we have focused on improving starch levels, so growers who choose one of the newer varieties will invariably find they are moving up on starch percentage points by at least 1-2.
“Starch content can be tweaked by manipulating plant population and adjusting harvest dates, but varietal choice will have the biggest influence on the quality of the end product.”
Another element to consider is the variety FAO number, which is an international indicator of hybrid maize maturity, adds Mr Burgess.
“It is only recently early varieties with a maturity rating of 150 have been introduced. The market has responded to environmental concerns over late harvests, which can increase the risk of soil structure damage and soil run-off.
“Varieties which permit an early harvest have also allowed the expansion of the geographical area in which it is possible to grow a successful crop. In addition, a variety which is ready to cut two or three weeks ahead of its rivals can be left to mature in the clamp for a longer period – the ideal figure is six weeks. In trials, palatability and starch degradeability in the rumen has been shown to be improved in a more mature maize silage.”
Growers who take advantage of using the KWS free online soil temperature service as a tool to guide drilling dates are finding benefits, reports Mr Burgess. He feels it will be particularly relevant this season.
“We have had a few consecutive mild springs and it is all too easy to become complacent and rely on previous sowing dates for drilling date decisions. However, the long spell of cold weather combined with a particularly wet winter, have exacerbated the need to exercise patience.
“As well as having an effect on nutrient uptake, soil temperature regulates maize growth up to the 4-5 leaf stage. The small canopy of the young plant compromises its ability to intercept sunlight and this will prevent the roots from sourcing soil nutrients, especially in low temperatures.
“Our soil temperature service provides the local figure at 10cm, to give an indication of the conditions into which the roots will grow. It also supplies information on soil surface temperature, to highlight the risk of frost,” says Mr Burgess.
Francis Dunne of Field Options stresses the availability of key nutrients is essential for the successful early establishment of maize, pointing out the crop has a poor metabolism at low temperatures. In certain circumstances, a starter fertiliser will enhance early vigour, leading to better cob development and resulting in earlier ripening, higher yields and increased energy content.
“The greatest response to a starter fertiliser is seen where growers plan early drilling and following a cool spring, especially if the land has a low nutrient status,” says Mr Dunne. “It is also advisable when choosing varieties with low vigour, and when growing on marginal sites.
“Di-Ammonium phosphate (DAP) has always been the industry standard, but it ranges in quality and that can cause problems with the sensitive metering on maize drills. Significant crop responses rely on the accurate placement of phosphate, sulphur and zinc.
“A specialist maize starter fertiliser will contain all of the main nutrients, plus humic compounds, to further enhance availability, allowing the use of lower rates and giving a similar response to DAP.”