Monitor soil conditions and drilling depth (March 25)

As producers look ahead and prepare for the 2025 maize-growing season we share some timely advice on varietal choice and seedbed management.

TEXT WENDY SHORT

Maize crop performance in 2025 was variable and described, overall, as ‘acceptable’ by agronomists and producers alike. But what can growers do to improve this year’s crop and ensure that 2025’s forage is better than ‘OK’?

KWS’ Tom Turner says that they should start by looking at variety choice: “This is key to achieving yield and quality targets. Matching variety to location and soil type is crucial, and projected harvest dates must also be considered,” he explains. “It is also important to take the long view, using five-year average results for the unit, rather than basing decisions on 2024 performance. So, even if the previous year was disappointing, avoid knee jerk reactions to that.”

He adds that some of the modern ultra-early and early varieties have a short growing season and can help to bring forward harvest dates, without a significant yield compromise. They are particularly appropriate on units that have signed up for maize SFI options, because these require a window for establishing winter cover.

“That said, later-maturing varieties can be useful where maize represents a high percentage of TMR diets, as they combine high energy yields with moderate starch content. This can reduce the risk of acidosis.”

He also urges producers to remember that maize prefers a relatively light, warm seedbed. “Maize plants do not perform well in compacted soils. The most cost-efficient option is to create a seedbed that allows maize to root freely, and a sub-soiler may come in useful. This will require fairly dry conditions, as the soil cannot be in a ‘plastic’ state. So an assessment of soil friability is essential to minimise soil-structure damage. Exercising patience is critical and the same applies to drilling.”

When it comes to herbicides, he says that a drive to reduce input costs can influence spraying strategies. “But young maize is highly vulnerable to competition. So I always recommend using a pre-emergence and a post emergence herbicide as an insurance policy.

Crop emergence: soil temperature at drilling impacts success

Weed competition

“Maize will fail to get off to a good start if it is faced with early weed competition. A pre-emergence spray will ensure that weed growth is tackled at the outset, particularly if the weather causes delays in the application of a post-emergence treatment.”

Mr Turner also stresses that it is crucial to wait until the soil temperature reaches a consistent temperature before sowing maize seed. “Soils must have reached 8OC for four consecutive days on light soils and 12OC on heavy soils,” he stresses. “Yield penalties will apply if drilling is premature, with a harmful effect on germination rates and an uneven pattern of emergence, as well as limiting nutrient uptakes.”

Conversely, late drilling will delay cutting dates and may take some units into a period that is less than ideal for harvesting.

“This can result in crop yield and quality losses, along with soil-structure damage, which can have a negative effect on the following crops. On units where drilling can be subject to delays, early-maturing varieties will allow for a degree of catch-up,” he adds.

Drill settings will depend on sowing timings. “As a rule, use 5cm for April and early-May sowings, followed by between 5cm and 7cm for mid-season drilling.

Soil moisture

“Planting was pushed back in 2024, due to high rainfall and low temperatures on many units. And if this applies again in 2025, drilling up to 9cm may be relevant on light soils, to give seedlings access to vital soil moisture.

“In dry conditions, it is advisable to use a fairly deep drill setting, which can promote rooting and minimise the risk of lodging later on in the season.”

The flip side is that a drill setting that is too shallow can reduce plant stability and this particularly applies to maize grown on exposed sites and/or at high altitudes. “It will also prevent the seedlings and young plants from accessing water in a drought situation. Hopefully we will not see a repeat of 2024’s cold, wet spring so that drilling and crop-management timings can follow their usual pattern.”

Drill settings also need to be carefully monitored. “Settings must be checked and double-checked throughout the sowing period, whether the producer is in charge of the operation, or a contractor is being used. Inaccurate settings will produce an uneven crop, and no variety can perform to its potential if it is poorly placed in the seedbed.

“Another issue that I see when crop walking is double planting. This will weaken the root structure and mean that some plants will receive more valuable sunlight, moisture, and nutrients than others.

“Whatever the weather ahead, it is important to follow the basic rules of agronomy when establishing a maize crop. Attention to detail will pay dividends,” says Mr Turner.

Drill depth recommendations

early-to-mid season (April to early May) - 5cm

mid-season (early-May onwards) - 5cm - 7cm

late season (mid-May onwards) - 7cm - 9cm