Maize Watch 2022: Lower yields result from summer drought

The maize harvest is progressing well in many parts of the country, with crops doing better than first estimated. However, the summer drought has resulted in lower yields in most areas.

This is according to Neil Groom of forage specialist Grainseed, which is collating samples for Farmers Weekly from across the country during the harvest season (see table below).

Three of the six farms taking weekly samples, in Norfolk, West Sussex and Derbyshire, have now harvested their crops.

Assessing clamp yield

“Once your maize is clamped, you can start to formulate a plan for winter feeding,” says Mr Groom.

“Many foragers now have accurate yield monitors, so they know how many tonnes have been clamped. If this is not available, measuring the clamp will give a good estimate.

“Normally, the density of maize silage in the clamp is 750kg/sq m, but if a SiloCompactor has been used, it could be up to 1,000kg/sq m.”

Ideally, the clamp should be sealed to aid good fermentation, he says. Once it is stable, a silage analysis should be undertaken every month and the ration adjusted accordingly.

The longer the maize is clamped, the more accessible the starch will become to the rumen bugs, he adds.

Devon harvest imminent

Chris Blake, who farms near Crediton in Devon, is sampling his maize for Farmers Weekly and intends to start cutting at the end of this week.

“We had some early September rains, which greened the crops up and saved the grassland,” he says. “Now we’re milking off grass again as the cows calve. Our maize crops are a mixed bag, but cobs are good.”

Much of Mr Blake’s maize is grown on neighbouring arable land, where an early harvest is needed to allow wheat to be drilled in early October.

Soil organic matter

Any fields not going into wheat will be drilled with Westerwolds ryegrasses and rolled to reduce the risk of soil erosion from maize stubbles over winter. It will also use nutrients available in the soil to prevent leaching.

These fields will be grazed by young heifers early in the new year before they are returned to maize next April.

Mr Groom says this is a good strategy to keep the fields biologically active and help maintain soil organic matter levels.

“When grasses are in the rotation, we will often see soil organic matter levels at 8% or more, whereas arable soils will be below 3% and often about 1%. Soil structure, nutrient and water-holding capacity are all improved from the inclusion of grassland in the rotation,” he says.