Changing nitrogen sources, using inputs more effectively and adopting min-till cultivation techniques can all be used to reduce the carbon footprint of malting barley.

This is the message from an ongoing programme of grower training days run by the HGCA, Muntons Malt and NIAB TAG. The aim is to bring together growers and processors to enable a better understanding of the role they both play in reducing carbon emissions.

There are two key drivers behind the need to reduce the carbon footprint of the malt supply chain. First there is current and potential new government legislation and second, there is increasing pressure from consumers.

“Our environmental impact is more at the forefront than ever,” says HGCA director Rebecca Geraghty. “We are approached on a daily basis by customers who want to know how green we are.”

Muntons latest research estimates that more than 60% of the carbon emitted to produce the finished malt comes from the growing process. “We need to know where we can influence our carbon footprint without making life more difficult,” highlights Nigel Davies, manufacturing and technical director at the firm.

Growing the barley crop is an area that Muntons believes can achieve the greatest carbon reduction to their final malt product with minimal effort. The largest contributor to the carbon footprint of growing malting barley is nitrogen fertiliser, at nearly half 48%, while nitrous oxide accounts for 35% and fuel for 17%.

Dr Davies points out that if most emissions from the growing of malting barley come from the use of artificial nitrogen fertiliser, then the sector should look for low-carbon alternatives.

Fertiliser manufacturers are already installing scrubbers to reduce nitrous oxide emissions by 90%, such as Yara which is using N2O catalytic abatement technology.

But green waste, he argues, is another such alternative, though unlikely to fully replace artificial nitrogen fertilisers. It does not have the stigma or complications of sewage sludge, but can provide a significant proportion of the nitrogen needs of malting barley.

“Green Compost doesn’t just help reduce carbon use, it can also help with water retention, so helping crops cope during dry spells,” he says. “there is a financial saving – using compost can result in growers using up to 60% less nitrogen fertiliser.”

However, he stresses that green compost used on malting barley has to be PAS 100+ certified, a quality standard for green compost that eliminates the potential for contamination and is free from materials that can taint the barley, such as onion, leek or garlic waste.

Ron Stobart of NIAB TAG points to the use of cover crops to improve soil fertility as another means of reducing artificial fertiliser rates. For example, spring barley with a trefoil cover crop and a 75kg/ha nitrogen rate achieved a yield improvement of 0.25-0.50t/ha over land at the same nitrogen rate, but with no cover crop. Lower nitrogen rates achieved proportionately greater yield differences.

Another way that growers can reduce their carbon footprint is by looking at their fuel use. Soil cultivations can have a high fuel requirements, so growers could consider more fuel-efficient alternatives to traditional cultivation techniques.

Research into the fuel demands of various cultivation techniques is ongoing, but data collected by machinery manufacturer Amazone’s Tikhill trials would suggest a big difference between the fuel used for deep ploughing (35 litres/ha) compared with minimum tillage at (7.7 litres/ha) which could translate into a significant reduction in fuel use and a similar reduction in carbon emissions.

Ian Beecher Jones, independant precision farming consultant highlights that precision farming practices already being used to increase efficiency of valuable inputs such as nitrogen are also reducing the carbon footprint. “If we make more money we are probably reducing our footprint because we are using our inputs more efficiently” he says.

Understanding how exactly precision farming will reduce a growers footprint is dependant on a number of factors. Mr Beecher Jones points out that the key is to understand your current position and the potential savings you can make before investing in technology.

Muntons has already reduced the carbon footprint of its malt with the installation of the most energy-efficient kiln heaters available, which have a zero year payback, saving 8% a year on gas costs and giving the company CO2 credits, which can then help to reduce its tax bill.

Calculate your own carbon footprint

To help better understand carbon footprinting Muntons has worked with the Centre For Low Carbon Futures and the Stockholm Environment Institute to develop a carbon calculator specifically aimed at malting barley growers.

Growers answer nine diferent questions on yield, seed quantities, fertiliser usage and tractor hours. The Calculator will then use this information to generate the growers carbon emsissions. To access the calculator, go to www.muntons.com/about/carboncost.php

Green compost

Green compost and byproducts from anaerobic digestion offer many benefits to malying barley growers, according to Martin Wood, director of Earthcare Technical.

Ongoing trials are being run across the UK by ADAS with funding from DEFRA and the Waste Resource Action Programme (WRAP). “We are measuring and investigating the agronomic benefit of those two materials,” says Dr Wood.

“Green waste is useful source of P+K, but not necessarily nitrogen,” he says. Spread at the NVZ limit of 30t/ha the total nutrient value of the compost is around £170/ha. However, he adds that the supply of stable organic matter is the number one benefit from compost.

“Digestate is a relatively new material, we don’t know as much about it in terms of its fertiliser replacement value,” says Dr Wood.

“Nearly 80% of this nitrogen in food-based digestate is available, compared with only 45% in cattle slurry,” he adds. The financial value of the nutrients in a typical food-based digestate applied at 30cu m/ha is around £129.

“If you are considering using compost or digestate you should consult the purchaser of your crop and you should get an accurate analysis of that material.” Dr Wood also emphasises the need to ensure compost is produced to Pas100 standard and digestate to PAS110.