How two arable farmers apply manure to standing crops

Applying manures to standing crops in the spring can help to reduce fertiliser costs, improve soil condition and minimise environmental losses.

Tighter regulations, along with high fertiliser prices, are prompting a re-think about the use of manures on arable farms, with growers keen to get the most from the nutrients they contain while avoiding any leaching.

An important resource when used in the right way, manures do more than supply a range of crop nutrients, with their organic matter content also helping with soil health goals.

See also: How farm data integration could improve N use efficiency

“The nutrient value of these materials has more than doubled recently,” says Lizzie Sagoo, soil scientist with Adas.

“Getting their worth in terms of crop nutrients and organic matter content has to be balanced with losses from nitrate leaching and ammonia emissions.”

Nitrate leaching tends to be higher when applications are made during the autumn and early winter – when crops aren’t growing and rainfall is higher following application – so the shift away from the autumn spreading of solid manures is expected to gather momentum.

Farmers Weekly has spoken to two growers who are making  spring spreading in standing crops work.

Reducing fertiliser use

For Mr Suddes, who was named Soil Farmer of the Year in 2017 and is a member of the Green Farm Collective, the practice means that bagged fertiliser use continues to come down, while the farm’s hungry glacial till soils are being improved.

“We’re getting the benefit of the nutrients, when they’re most needed by the crops, and preventing the leaching losses that can occur from autumn and winter spreading,” he says.

Given current inflationary pressures, appropriate and accurate spreading of farmyard manure in the spring is also helping to peg his costs of production, while making good use of a resource already on the farm and smoothing out workloads.  

Soil health is much better, with earthworm activity and soil biology on the up, helped by the farm’s very diverse rotation and no-till approach.

Soil organic matter levels have risen over the years, with cattle manure continuing to be targeted at fields in most need.

Applications are generally made in March, just as soils are starting to warm up, when both worms and soil fungi are more active, so the manures disappear quickly, he explains.

“The worms get to work on it almost immediately,” he says. “They pull it into the soil profile, so we let them do the hard graft.”  

Having switched to direct-drilling in 2009, he is overseeing an integrated system that prioritises soil health and biodiversity, while reducing the farm’s reliance on synthetic inputs.

“I would expect to see crop damage if we were trying to put too much on,” says Mr Suddes. “Even when we first started, with our old 8m muck spreader, the wheat was undamaged by the spreading operation.”

Twin disc spreader

The purchase of a Richard Western twin disc spreader three years ago improved the practice and allowed him to spread it wider, going up to 48m in wheat.

In oilseed rape, he limits the spread to 24m, to protect the plants as they start to grow away in the spring.

“Having been no-till for 13 years, there’s no problem with getting a 24t muckspreader up the tramlines,” he points out. “Our soils travel very well now.”

A free-range poultry enterprise on the farm provides 800t of chicken muck a year.

It is analysed before it is applied at a rate of 5t/ha across the board, so that Mr Suddes knows how much nutrient is being applied and can match and top-up supplies to the needs of the crop.

He points out that a theoretical, much higher 14t/ha application of chicken litter would provide 250kg of nitrogen, of which 30-50% is available, on normal soils.

“More research needs doing, but there is tremendous nutrient value in these materials. They are soil conditioners too.”

Having 280 head of beef cattle at South Farm means that he is also able to make use of half-rotted manure, leaving it for three to four months before spreading it at a rate of 10t/ha.

He finds it preferable to do this in the spring, as autumn workloads are already very high and there’s a greater risk of leaching.

“Depending on the timing of application, the manure can also work as soil armour, helping to protect it.”

On one occasion, cattle muck was applied to a brome-infested winter barley crop just prior to T1, so that the weed population was partly smothered.

“It allowed the barley to grow away,” he recalls. “We were able to harvest it before the brome seeds were viable, so it helped with our weed control.”