What lessons can be learned from 2023 maize harvest?

Farmers harvesting maize later in October 2023 were plagued by wet and difficult conditions.

“Maize was a lot riper than people thought it was. Farmers were put off harvesting because the fields still looked green, but the cobs were ready.

“There was also a lot of fourth- and fifth-cut grass silage that contractors were still harvesting, and that was prioritised over maize,” recalls agronomist Ian Evans from BCW Agriculture.

See also: How maize is helping beef producer hit target weights earlier

“If you harvested it at the right time – at the end of September, into the first week of October – the crops were generally good quality, but crops taken later were too dry [up to 40% dry matter], and starch and digestibility were reduced because of higher lignin levels,” he adds.

Richard Hopwood, nutritionist from ACT, says some maize has struggled to hit 28% starch and dry matter is inconsistent.

“I have seen many variable maize samples this year. On average, yields are back two litres a cow [on the 2022 maize crop] and in beef cattle, it is costing 200g of liveweight a day.”

Richard says 2024 presents a good opportunity for farmers to plan for buffer maize stocks.

“Spring cereal planting is down because of the weather and the lure of SFI [Sustainable Farming Incentive], so it might be wise to consider growing more this coming harvest.”

Below, Ian and Richard reflect on where some growers went wrong in 2023 and offer advice to ensure a better harvest this year.

Select the right site

Varieties have improved to achieve early maturity and standing ability, but site selection is still imperative, says Ian.

“We have got blasé, thinking we can grow maize anywhere. Some people are still growing it on ground they shouldn’t be. Some farmers might need to admit they can no longer grow maize,” he warns.

He says fields should be:

• Free-draining and relatively flat
• South-facing and not too exposed.

Select the right variety

Farmers must choose the correct variety for their growing climate, stresses Ian.

Each variety has a Food and Agriculture Organisation (FAO) rating. This is an expression of the number of heat units the plant requires to reach maturity. Higher numbers indicate a longer growing season.

Ian says as a rough guide:

• In the North, a variety with an FAO rating of 160 is suitable
• Further south, use a variety with an FAO of 180-200
• In the Midlands, choose a variety in between these (FAO 160-180).

Growers may need to use a selection of varieties to suit different fields and stagger harvest, he adds.

For a precise guide, farmers can use the Maize Growers Association’s site and maturity group selector.

This asks questions about altitude/aspect and rainfall, for example, and helps identify whether a particular field is suitable and which variety to select.

Richard says digestibility and starch are important feeding considerations and urges farmers to look for varieties that have been bred for these traits.

Get soil fertility and crop nutrition right

Ian says this year, farmers need to reset and get back to basics – and this includes ensuring soil is sufficiently fertile. He stresses: “Maize is a hungry crop that requires good soil fertility.”

He advises:

• pH should be 6.5
• Potash is required for cell division and growth (aim for index 2-3)
• Phosphate helps to stimulate root emergence (aim for index 2-3)
• The crop has the highest demand for phosphorus from the middle of July to the middle of August
• The earliest foliar nitrogen should be applied is mid-June
• Make sure the correct foliar feed is used to avoid scorching the plant.

Alleviate soil compaction

Soil compaction is likely to be an issue this year because fields are still wet, and those that were harvested later in adverse conditions will have damaged fields.

“Wait until it dries and go in with a cultivator such as a Shakerator or chisel plough. Make sure the leg depth is working at the level of compaction,” says Ian.

Do not drill maize too late

Some farmers left it too late (June) to drill maize: the weather turned dry and the crop failed to germinate, he reflects.

The dry weather also caused “brackling” or snapping. This is because plants grew tall, causing cobs to form further up the stems, which then toppled over, explains Richard.

Ian says soil temperatures are typically warm enough to plant maize after 15 April. He adds: “The big secret is to be organised – get your fields prepared beforehand and put your contractor on standby.”

• Soil temperatures must be 8C at planting on lighter soils and 10-12C on heavier soils.
• Consider using film at planting. This can help bring harvest date forward by 14-21 days and boost yields, but it needs to be weighed against increased growing costs.

Be prepared to harvest earlier

To avoid crops going past their best and harvesting in wet conditions, check them regularly.

“Field assessments need to be done more consistently. No one considered last season how the unusually high winds dried crops rapidly.

“Plants need to be assessed weekly and you should take at least five to six cob samples in each field,” advises Richard.

• Check maturity by breaking off a cob, snapping it in two and carefully cutting a kernel in half. The milk line should be one-third of the way down the grain, and the other two-thirds should be showing set starch.

Consider leaving more stalk in the field

Last harvest, crop yields were high, which contributed to a reduction in quality, explains Richard.

“Typically, the plant-to-cob ratio will be 50:50. This harvest, it has been 65:35 in favour of the plant,” he says, adding that because the cob contains the starch, less cob means overall the crop’s starch content is poor.

He advises that if bumper crops grow this year, the cutting height should be raised to leave more of the stalk in the field.

Doing this will not only prevent quality from being diluted but avoid clamps being overfilled. Overfilling has led to higher forage wastage this year caused by aerobic spoilage.

He adds: “Avoid overfilling pits because it makes it difficult to consolidate and sheet. Instead, have a separate pile on a solid floor, which can be secured with a sheet.”

When harvesting, make sure:

• The chop length is 20-30mm
• Grain is cracked in half – large volumes of maize last harvest meant some grain was not cracked and passed straight through animals.

Choose the correct additives

In some instances, the wrong additives are used to suit the convenience of contractors, warns Richard.

He says ultra-low-volume microbiological additives are often used, because they cover more acres and prevent chopper downtime, when what is needed is a higher-volume, food-grade liquid preservative.

Microbiological additives preserve quality, while non-corrosive preservatives help cool the crop, control yeasts and moulds, and prevent heating, he explains.

Guidance on variety selection