Get to grips with crop nutrition

Alternative forms of crop nutrition will be under the spotlight at Cereals 2005. Paul Spackman looks at what the host farming company is doing already and what”s on display at the event.

TIGHTER CONTROLS on waste going into landfill and pressure on artificial fertiliser prices mean alternative sources of crop nutrition are an increasingly attractive option, according to Cereals 2005 host Velcourt.

Changes to landfill legislation in December will ban the dumping of class three waste, such as catering waste, in landfill. Velcourt”s Keith Norman believes conversion to a fertiliser in slurry or pellet form could offer a potential solution to waste management problems and provide farmers with a cheaper source of fertiliser.

The firm”s farms director Douglas Inglis agrees. “Increasing landfill taxes and restrictions on sewage sludge mean there is only really one place it can go – onto the land.”

Using local council composted green garden waste as a source of fertiliser is one such option, already being used by Matt Gregory, who manages Velcourt”s 930ha Greenwell Farms, near Orford, Suffolk.

 “For the past three years we have been part of a trial looking at varying rates of compost from 0-100 tonnes/ha to see what the nutrient and soil organic matter benefit is.”

Results so far show that where compost is used, organic matter levels have increased by 2-4 %.

Nitrogen rates can potentially be cut by 20-30kg/ha – something that will be tried this season, he adds.

Compost increases the water holding capacity of the soil, therefore it is only irrigated crops on light land with a high sand content that tend to show the real yield benefits, especially when applications are greater than 50t/ha. “Because compost is a waste product, we need to have approval to use it – especially on veg.”

While improving organic matter content has helped soil workability, the effects haven”t been great enough to change working practices at present, he says.

Fellow Velcourt farm manager Mark Wells agrees on the importance of improving organic matter levels. On his 400ha arable and dairy farm at Ixworth, near Bury St Edmunds, farmyard manure is applied to both maize and sugar beet land.

When applied at a rate of 15t/ha, the manure provides about 90kg/ha of nitrogen – based on RB209 re-commendations.

But while only about 10% of this is available in year one, it acts as an excellent soil conditioner, putting organic matter back into the sandy loam soil, he adds.

“It”s a good, cheap, available product and has definitely improved workability on the heavier land.”

All growers should pay attention to the nutrient status of soils to maximise productivity in the long term, adds Mr Norman. “It”s simply no use having a short-term rape and pillage approach.”

He suggests growers have a comprehensive audit done by an independent consultant to identify the status of soils, from micro nutrient content to cation exchange capacity.

Anyone wanting to use waste products as a fertiliser source will need to undertake such an audit as a matter of course, adds Mr Gregory. A test can typically cost between 75-100, but can be justified as it removes the guess work from soil management decisions.

Spotlight on the latest technical innovations 

Throughout the build-up to Cereals 2005 on June 15 and 16, near Royston, Herts, farmers weekly and FWi are working with hosts Velcourt to give you a behind the scenes look at the latest technical innovations on show.

Four leading nitrogen application models will be tested against each other – Rothamsted”s Sundial, Yara”s N-Plan, the Kemira Growhow package and the PLANET software. Initial results have found recommended N rates varied by up to 100kg/ha across the models – some of which can be put down to the amount of information fed into each one, says Velcourt”s Paul Cartwright.

 Also under the spotlight is the biological conversion of catering waste to fertiliser at temperatures which sterilise any dangerous pathogens, says the firm”s Keith Norman.

 “At present, the end product comes as a slurry, but studies are now looking at dehydrating this to pellet form. Nitrogen contents are quite low – around 4% – but it is hoped this can be increased to over 20%.”

 Velcourt is also looking into biofortifying wheat with selenium amended fertilisers to enrich bread products. Selenium has a host of health benefits, including improving male fertility and reducing the risk of breast and prostate cancer, says Mr Norman.

 Adding slow release agents to liquid fertiliser will also be looked at. “Slow release N on sandy land that is growing vegetable crops under fleece has given us an extra two weeks of N,” says Suffolk farmer Matt Gregory. But Velcourt”s Douglas Inglis reminds growers that N release will be primarily determined by soil temperature – as temperatures increase, more N becomes available.