A focus on improved root structure and quicker emergence will be vital for maize crops this season to reduce the impact of water-logging and compaction following the wet spring weather, warns George Hepburn, QLF Agronomy.
He explains that attention must be paid to soil structure in maize planting sites, particularly areas where maize is cropped continuously, as yield losses can often be seen as a consequence of compacted soils.
“Robust tillage and the fact that it needs to be harvested with heavy machinery at a time when conditions can be wet are the main causes for compaction,” says Mr Hepworth.
The benefits of farmyard manure (FYM) are often overlooked, but Mr Hepburn explains that they can contribute towards making maize crops very cost effective, he says: “When managed and applied correctly it can be one of the best forms of fertiliser. What’s more, these types of fertiliser are generally free, making them a very cost effective.”
Rather than seeing FYM as a bulky and heavy waste product, Mr Hepburn explains that as well as providing Nitrogen, Phosphorus and Potassium, it is also high in organic matter, helping to improve soil structure and also provides a food source for the soil biology.
Mr Hepburn explains that assuming FYM is 25 per cent dry matter, cattle FYM can provide 6kg/t N, 3kg/t P and 8kg/t K, taking into account current fertiliser prices this equates to a value of over £10/t.
“This means that at a typical application rate of 25t/ha, cattle FYM can provide up to £125 worth of available nutrients that do not need to be paid for,” he says. However values in FYM can vary so it is advisable to get an analysis. See the table for more information.
“However, to unlock its full potential I would recommend including a carbon source, such as molasses, pre and at planting. This really helps stimulate the soil biology by providing an energy source which aids the breakdown of the organic matter in FYM into a more readily available format for the plant in a shorter time period,” says Mr Hepburn.
A trial found that applying a liquid carbon based fertiliser at 20l/ha, pre and post emergence caused an 11 per cent increase in yield and a lift in starch, alongside quicker emergence and a larger root mass, compared with a control group which did not have the fertiliser.
Mr Hepburn says: “This was mainly due to better availability of nutrients which meant that crops were able to get up and away from pests and disease and build better root structures.
“Therefore, including a naturally derived fertiliser which improves soil structure and maximising its availability with a carbon source could be extremely valuable this season to not only help the bottom line.”
To help with the control of weeds in maize crops, Ed Stevens, Hutchinsons Agronomy Services explains that rapid emergence and a vigorous crop should be a priority. Growers should be prepared to be patient with drilling dates depending on the weather and make good use of seedbed fertilisers.
“Once it has reached the six to eight leaf stage, the crop can withstand and out compete most weeds,” he explains.
Pyridate, a post-emergence herbicide, has proved to be effective when used to ensure crops remained weed free in the critical six-week period following drilling.
When trialled in crops of both forage and seed maize, Pyridate, was able to get on top of mugwort and crane’s bill, as well as more common broad-leafed weeds such as fat hen and chickweed.
Pyridate has been found to be very effective when combined with other herbicides such as Callisto and Calaris, however Calaris will be withdrawn in February 2019.
Maize crops can be very vulnerable to weed competition in early growth stages, post-emergence treatments should be applied when the first cotyledon weeds show.
When it comes to application, Mr Stevens advises the use of angles nozzles, “They allow the spray to penetrate and reduce the impacts of any shading by the maize plants.”