Harnessing cover crops to beat climate change
As featured in Arable Farming Magazine
Harnessing cover crops to beat climate change
by Arable Farming October 2020 issue
While hard figures on cover crops benefits can be difficult to come by, one project involving East Yorkshire vining pea growers aims to change that. Marianne Curtis reports.
A farm-based project that it is claimed could help return atmospheric CO2 to pre-industrial levels has been launched in East Yorkshire.
As well as having the potential to counter the effects of climate change, the Sustainable Landscapes Humber Project could also help reduce flooding and improve soil health.
The project is a collaboration between Yorkshire Water, Birds Eye and supply chain consultancy Future Food Solutions.
Research expertise is being provided by the University of Hull, with support from Teesside University.
However, at its core are more than 40 farmers from across East Yorkshire and North Lincolnshire, based in the Yorkshire Water catchment area, who grow vining peas for Nomad Foods-owned Birds Eye.
The Sustainable Landscapes Humber Project involves these farmers growing cover crops before or after vining peas.
The cover crops dubbed pop-up rainforests by Future Food Solutions are made up of a number of plant species chosen for their ability to capture large amounts of CO2 from the atmosphere, says Future Food Solutions director Paul Rhodes.
Pre-trials funded by Yorkshire Water and facilitated by the UK Birds Eye agricultural team show growing cover crops can increase soil organic matter by
up to 40 tonnes per hectare, which can sequester more than 4t of atmospheric carbon per year.
As soil organic matter has fallen by 50% over the past 60 years, using cover crops to restore these levels has the potential to re-establish soil health, but could also help to reverse the ongoing rise in atmospheric CO2 levels, according to Mr Rhodes.
The pre-project trials have already achieved a rise in soil organic matter, more than doubling levels in just five years, from 3% to more than 6%.
James Young, agriculture and vegetable sourcing director, Nomad Foods, says:
We have a rich history in the Humber catchment area, having worked with local farmers for more than 60 years growing the highest quality peas for our
Sustainable agriculture is at the heart of our company purpose at Nomad, and has always been at the core of the partnership with these farmers.
Therefore, were very excited to be involved in this project and to have the opportunity to work collaboratively with partners on finding solutions to issues such as climate change and flooding, as well as improving soil health for future crop production.
As well as Birds Eye, Mr Rhodes sees opportunities to get other brands involved in the project, particularly those which buy wheat for flour for Yorkshire puddings,
or those which buy malting barley and oats.
The benefits to the supply chain are significant, creating zero carbon food chains and cover crops are part of that.
Project participant Paul Martinson adds: It is a story we can tell which makes the potential market a little bit more than simply a commodity market.
In the field Paul Martinson, Yokefleet, Goole
Paul Martinson farms 380 hectares at Yokefleet, Goole.
Soils range from blow away sand to heavy clays and the rotation includes wheat, barley, oilseed rape and vining peas, with more spring crops this year.
Vining peas have been grown on the farm since 1969. Mr Martinson has been growing peas for Birds Eye since the mid- 1990s. Peas are grown within a 30-mile radius of the Birds Eye factory and from harvesting to freezing takes only 2.5 hours.
Drilling of peas began in April and finished on June 10 this year, with harvesting of the earliest drilled crops starting on June 18.
Mr Martinson says: Yields have been good we averaged 4.7t/ha.
The Sustainable Landscapes Humber Project involves 40 growers, all members of the Green Pea company, explains Mr Rhodes.
Half of the growers are growing a cover crop after peas and before wheat, and half will grow the cover crop after wheat or barley and before peas.
The aim is to improve soil organic matter and workability, help deal with soil-borne pests and diseases and help prevent flooding by increasing soils water absorption capacity.
For the trial, Mr Martinson planned to grow one cover crop before peas and one after.
However, he did not have time to sow his post pea cover crop due the weather delaying the pea harvest, meaning there would have been insufficient time for
the cover crop to mature before preparation for the following wheat crop to be planted.
For the pre-pea cover crop, Mr Martinson has drilled a cover crop of oats and phacelia.
It will be allowed to mature in the next few months, improving soil condition until he starts the preparation for drilling peas next year.
The amount of above ground biomass created by the cover crop at its peak will be measured, says Mr Rhodes.
We will take samples and Lancrop Laboratories is measuring nitrogen, phosphorus, potassium and dry matter content. From what is above ground we can calculate the below ground biomass and work out how much carbon is sequestered and what levels of nutrients are captured.
From total carbon we can work out soil organic matter level and come to a value in terms of the amount of carbon sequestered and the value of the nutrients captured. As they break down, they are available to the next crop which can reduce the nitrogen bill and carbon footprint. Nitrogen requirement of wheat is 70% of the carbon footprint for the crop.
Improving soil organic matter increases the workability of soil, enables it to hold water when it rains and helps boost water availability if there is a dry spring, says Mr Rhodes.
Mr Martinson is looking forward to getting hard data on the impact of cover crops.
He says: Cover crops are in vogue, but getting real data back to see the benefit thats the attraction.
He has already been taking steps to improve soil organic matter content on-farm.
We went out of beef in 2001 and have recently gone back in as soil was lacking in farmyard manure.
Improving soil organic matter by 1% means it can hold 200,000 litres/ha more water, says Mr Rhodes. This could make a contribution to reducing flooding in Hull, where the River Humber flooded in 2013.