Soil focus key to sustainability drive
As featured in Arable Farming Magazine
Soil focus key to sustainability drive
by Arable Farming Magazine July 2022 issue
Homemade compost, reduced tillage and cover cropping have been central to improving the arable sustainability on one Worcestershire farm.
A combination of challenging silty clay land, contract-farmed with heavy kit for many years, and lighter sandy gravel ground that continues to be rented out for field vegetable production has not made for an easy transition to a more sustainable arable system at Agriis Green Horizons Network farm at Salford Lodge, Pitchill, just outside Evesham, over the past decade.
And host farmer Tom Hughes efforts to match both the productivity and low environmental impact of the substantial broiler business developed and run by his parents, Malcolm and Liz, remains very much âa work in progress.
Even so, the improvements he and his agronomist have made so far are obvious in reductions in black-grass and brome problems, in far better structured and more resilient soils, and in the all-important bottom line not to mention results from the first year of ADAS YEN Zero benchmarking.
Fresh from working on a progressive Wiltshire downland unit, Mr Hughes came back to the family business in 2013 to take the land in-hand.
He recalls âjumping in at the deep end with the 120 hectares of heavy ground not in vegetable production, full of enthusiasm for a no-till approach.
With all the land rented out until then, we had no machinery at all, he says.
The ground had been demanding increasing amounts of horsepower to support deep working and power harrowing.
Unsurprisingly too, given the poor soil conditions, black-grass counts were knocking on the door of 1,500 heads/sq.m.
This certainly focused the mind and drew us to Agriis heavy land work at Stow Longa which has heavily influenced our thinking.
We were tempted to do a reset with the plough.
Instead though, we decided on a winter of intensive multiple stale seedbeds followed by five years of no-till spring cropping.
At the same time, we mole ploughed the whole area to link in with the drains my parents installed in the 1980s.
After alternating spring wheats and linseeds followed by canary seed, our first crop of winter wheat in 2019 averaged 10.75 tonnes/ha with no black-grass in sight.
It was a good year for wheat, but this clearly proved the value of our soil-centred approach.
In 2016, the vegetable ground was brought back into the rotation to address the worryingly low organic matters and poor structure, making the soils very prone to capping in the wet and baking hard in the dry.
Good quality land with irrigation is at a premium locally.
So, it makes sound economic sense to keep renting it out.
But field vegetable growing is not the most compatible with a no-till approach.
By cropping the ground themselves three years in every four and working closely with their vegetable-growing partners, the team has made sure soil improvement efforts are not compromised by the lands year in vegetables.
Theyve been very receptive to this, says Mr Hughes.
We now have full overwinter cover ahead of every spring-sown crop, together with a programme of sustained annual organic matter addition.
When we hand ground back for the vegetables generally after a winter cereal our partners spread certified green waste.
We then establish the winter cover with a mix of species designed to suit their following crop on contract.
At the same time, we are working closely with them to reduce their tillage.
Integrating this land into the arable business instead of leaving it permanently rented out has added a further complication.
Poultry litter from the familys 10 broiler sheds has been important in improving the rest of the acreage, but this cannot be applied directly within the vegetable rotation.
To address this issue, Mr Hughes has developed his own simple but very effective composting operation.
This involves mixing the litter with chopped straw from the farms 100ha of soft wheat grown for the broiler rations and grass silage from its 35ha of zero input grassland which has to be removed annually under a stewardship agreement.
Mr Hughes Agrii agronomist Kathryn Styan says: The grass silage adds extra green material which aids the composting process.
With a nicely balanced analysis, including 24kg N/t and good amounts of phosphate, potash, magnesium, calcium and sulphur, the 1,000t made annually has proved a much better manure than pure poultry litter.
Its also just right for spring top dressing the winter wheat, overcoming the fundamental conflict between direct drilling and the requirement to incorporate organic manures.
The active worm populations we now have in our soils naturally incorporated it in remarkably short order following application.
Weve seen huge benefits from using the compost as widely as we can alongside our least cultivation, continuous green cover approach.
Organic matter levels are up to 8% in places and all the soils hold water and drain infinitely better.
Ground we could seldom walk in winter without getting covered in mud or sinking in, now scarcely leaves a mark on our boots, or on the soil.
Organic manures providing 20-35% of the N we apply to our wheat is a big financial win these days.
We only used 180kg/ha of N overall on wheat averaging 9.8t/ha last season 40kg/ha less than the year before.
Results from the six fields of winter oats, winter wheat and forage maize we entered into the initial year of YEN Zero last season as part of the Green Horizons initiative are also very encouraging, she adds.
The yields Tom has been averaging for each crop are at the top end of the project results, while the greenhouse gas emissions remain some of the lowest.
All crops scored especially well for emissions from the key areas of operations and synthetic nitrogen production and application.
Operational emissions reflect the extent to which cultivations have been minimised at Salford Lodge.
Central to this is the 4.8-metre trailed Weaving GD drill used for all arable and cover crop sowing and chosen for the effectiveness of its angled double disc coulter system in cutting and closing the slot as well as the accuracy of its seed placement.
Mr Hughes says: Soil improvements are allowing us to direct drill more crops more effectively every year.
Our ground is becoming much more resilient to weather and machinery too.
But we still need to relieve the panning which is inevitable in our silty clay soils.
We also have to eliminate the system of beds used for vegetable growing and incorporate substantial crop residues.
We have three bits of the cultivation kit which we use as sparingly as possible all from Weaving.
We started off by retrofitting their ultra-low disturbance legs to a Subdisc for deeper working but now rely far more on the LD topsoiler at just six inches.
After vegetables the lightweight Shortdisc is our first choice for tackling the residues left behind.
While they accept some cultivation will remain inevitable at Salford Lodge for the foreseeable future, in no way does this lessen their enthusiasm for cover crops.
Cover crop mix
From a simple combination of mustard, black oats and tillage radish, they are currently trying a 12-way mix based on vetch, sunflower and black oats with four species of clover, fodder and tillage radish, buckwheat and phacelia on the heavy ground ahead of linseed, and on the light ground ahead of maize.
In addition to widening the diversity of rooting and biology, they see this as the best insurance against changing conditions, knowing that some elements of the mix will always establish well but they are likely to be different ones in different seasons.
We match our covers very much to the time of sowing as well as the following crop.
Early harvested vegetables give the best opportunity for them to work ahead of either autumn-sown cereals or maize in spring, so we tend to use more complex mixes here.
Even after vegetable crops coming off as late as October, though, we think its important to get something in generally something simpler and cheaper at a higher seed rate.
This is more to protect the ground from rain impact than to do much good structurally,says Ms Styan.
With the challenge of making the 70ha of maize they grow annually for a local AD plant more sustainable, the Salford Lodge team tried establishing a crop into a more permanent clover mix last season.
They set up the ground with the LD topsoiler, applied compost then matched the drill to the LDs leg spacing with GPS and blocked-off coulters.
Not having a precision drill, however, made for very uneven sowing, leading to much poorer yields than the 40t/ha they generally harvest.
Serious weed problems which had to be sprayed off also meant the clover was lost.
Undeterred by this, the team remain determined to maintain the pace of their sustainability improvement especially as far as maize is concerned and excited by the opportunities they see to do so.
Among their positive experiences on the cereal side, they have been harnessing variable rate seeding to even up field performance; using LiquiSafe liquid fertiliser treatment to eliminate at least one spring pass; better balancing crop nutrition to improve overall nutrient use efficiency; employing biologicals at T0 and T3 to reduce reliance on fungicides; and using yield mapping and Gatekeeper to track their progress.
Mr Hughes says: We are putting lots of little things together in our soil-focused approach to improve what we do in crop production alongside and as closely as we can with all the other environmental and carbon improvements being made by our broader family business.
These include 15ha of short rotation willow coppice and a wood chipping operation; 10 biomass boilers, 23 air source heat pumps, plus a new ground source installation and a 10ha array of solar panels.
Having my brother George so heavily involved at the sharp end of a renewable energy and carbon sequestration business is a great help here, making what we are doing part of a truly integrated family-wide effort, adds Mr Hughes.