Developing practical solutions to drive sustainability – Fruit & Vine
From cutting carbon emissions to new habitat creation, the increasing focus on sustainability is manifesting itself in many different ways on UK farms, orchards and vineyards ...
Many factors are driving the need to improve sustainability, often centred around the environment, such as government targets to hit net zero by 2050, and policies to enhance biodiversity, or protect natural resources.
Such high-level targets are filtering through supply chains, and increasingly affecting the decisions growers make; a trend that is only likely to continue in coming years.
The launch of the Sustainable Wines of Great Britain (SWGB) initiative in 2020, is just one example. It aims to put sustainability at the heart of the English and Welsh wine industry, and has already attracted many leading vineyards.
Supermarket buyers are also talking more seriously about their ambitions to source ‘low impact produce’, at least at a strategic level, although price inevitably remains a major driver of buying decisions, especially during tougher economic times.
“But buyers know they still have targets to meet and growers will play their part in helping to decarbonise the supply chain,” Hutchinsons agronomist, Rob Saunders says.
While environmental and social considerations are often at the heart of the sustainability agenda, financial aspects are equally important, he adds.
“You can’t talk about sustainability and just focus on environmental or social aspects. We’re in a capitalist system, so production has to be financially sustainable as well.”
Equally, profit cannot come at the expense of the environment or other capital resources, whether labour, or the soil, he adds. “No business that derives its income from running down its capital base can credibly report a profit.”
It’s a concept that lies at the heart of the ‘triple bottom line’ accounting framework, often shortened to ‘the three Ps’; profit, people, and the planet.
None are mutually exclusive, of course. More targeted fertiliser application, for example, benefits crop growth, the environment by reducing the carbon footprint, and the bottom line through cost savings, while profitable businesses secure employment and support rural economies.
“So much of sustainability is about efficiency of resource use,” Mr Saunders adds. “One of those resources is land, so we need to make the very best use of the land we’re deploying. By driving upyield per unit area, you are invariably driving down the resource use per kilogram of output, whether that’s sprays, water, fertiliser, or labour.”
Digital mapping and precision technology are playing an increasingly important role in improving efficiency, and making businesses more sustainable, Mr Saunders says.
Many growers are already realising the benefits of TerraMap high-definition soil scanning, for example. The system uses passive, gamma-ray detection technology, to produce a high-definition map (based on 800 data points per hectare) showing all common nutrient properties, pH, soil texture, organic matter, carbon (organic and active) and cation exchange capacity, plus elevation and plant available water.
The data highlights variability across sites and allows subsequent management to be targeted more accurately.
Given the wealth of data potentially available to growers, systems such as Omnia are invaluable for providing a central ‘hub’ to record, store and analyse information, including TerraMap soil scans, crop observations, or weather data.
Omnia’s weather forecasting capability is particularly useful, especially when combined with pest and disease forecasting models to predict threats such as scab, canker or mildew.
Improving orchard sustainability Hutchinsons is involved with several projects that are looking to improve the sustainability of production systems across orchard and vineyard sectors, utilising the latest tools and techniques.
One such example is the 10-year Helios project, now halfway through, which is investigating whether higher orchard yields can be sustainably achieved by redesigning canopy and tree architecture to better utilise sunlight. Designs are also ‘robot ready’ with a view to greater mechanisation in the future – something that may be the main way to overcome ongoing labour shortages in the sector.
Initial findings from the first five years show promising results, as well as highlighting various challenges still to overcome, particularly around the speed of tree establishment in some growing terms.
“Orchards don’t pay back until at least years five, six or seven, so it’s a bit early to pick out the best systems,” says Mr Saunders. “Most orchards look good when young, but it’s keeping them productive in later years that can be the challenge, as productivity declines as trees age, and diseases such as canker inevitably creep in.”
But, it is changing consumer trends that potentially present the biggest challenge, as varieties come and go out of fashion. Cox, for example, was replaced by Gala, and now Gala orchards are being replaced by the likes of Jazz, Kanzi and Pink Lady.
“The varietal treadmill is speeding up, which means new varieties coming along now will have a shorter lifespan than those that have gone before, so the focus on rapidly establishing an orchard and getting early payback has to be even sharper.”
At Helios, the V-system of growing has shown a particularly impressive yield build up, with excellent quality, however it is not suited to machine harvesting. One of the most promising systems so far has been the low cost M116 rootstock orchard, which is shaping up well with a lower upfront capital investment.
A separate project is aiming to find more sustainable uses for old orchard trees that have reached the end of their productive life, and help growers reduce their carbon footprint, by producing biochar.
The idea is that because biochar is extremely resistant to bacterial breakdown, it is able to lock away carbon in a more stable form, reducing the amount lost to the environment.
Producing biochar involves carbonising the wood from old trees under high temperatures (300-1,000℃), in the presence of little, or no oxygen; a process known as pyrolysis, similar to charcoal production. This leaves behind a solid material containing around 80% elemental carbon, that can be used as a soil improver, and a long-term carbon store.
Mr Saunders says biochar sequesters around half of the total carbon contained within trees, and its application to soil could provide a way of increasing organic matter beyond the natural equilibrium.
“Many people don’t realise there is a maximum level of organic matter that any soil can support, beyond which it starts to cycle and oxidise more quickly, so adding more organic matter beyond this point simply isn’t effective.”
The organic matter ceiling is linked to clay content, with more clay-based soils able to achieve a higher equilibrium than sandier soils.
“The only way you can increase organic matter content beyond the natural ceiling is by either flooding land to create a peat bog, or by adding biochar.”
Within the two-year project, Hutchinsons is working with Edinburgh University to conduct detailed life cycle analysis of orchard cropping. It is also undertaking agronomic evaluations of biochar use in new, and recently planted orchards, looking at the impact of high and low doses on soils and orchard productivity.
“If we can positively influence some characteristics of orchard trees, especially young tree establishment, through improving nutrient availability, building soil organisms, increasing moisture holding capacity of the soil, or building better soil texture, and potentially getting trees into full cropping one year faster, that will have a very significant impact on the viability of an orchard.”
The team will also look at other aspects, such as whether biochar use increases the calcium, or dry matter content of apples, which in turn could affect storability.
“Other parts of the world, such as Germany, Scandinavia and the US, are ahead of us on this, so the UK is behind the curve, with very limited orchard-specific data on biochar use. There are lots of unknowns, which is why we’re doing this project.”
Although work is focused on orchards, the principles apply elsewhere, including vineyards, where large amounts of material are often removed on an annual basis, says Mr Saunders.
In large, productive vineyards, there may be scope to bale up prunings to use as a feedstock for turning into biochar, as well as removing material and reducing the risk of disease carryover. “It’s potentially adding another output from the vineyard, providing wine, employment, environmental services in terms of biodiversity, and carbon sequestration.”
There is increasing interest in sowing green covers in many situations to suppress weeds, improve soil health, and build biodiversity. They also offer an added aesthetic factor, which may be important to those who open sites for public events or tourism.
Using cover crops to improve soil health in hop gardens is the subject of one Innovative Farmers project.
“It comes from the realisation that at the end of a cropping cycle, the entire hop plant is removed, and growers understandably don’t want to put old material back onto the land for fear of spreading disease, notably verticillium wilt,” says Mr Saunders, “So, over time, soil organic matter declines.”
Growers typically counter this by importing other sources of organic material, such as straw, compost and manure, which can be expensive, and raises the risk of damaging soil structure when running heavy spreading equipment on wet soils outside the growing season.
“We’re therefore looking at growing organic matter in-situ, by establishing a cover crop just ahead of harvest, which is then terminated in March or April the following year, so it’s not competing with the hops.
“This introduces a lot of organic matter into the hop garden without needing to buy it in.”
Concerns about verticillium wilt risk limit the cover crop species that can be used in hop gardens, Mr Saunders acknowledges, but monocots are unaffected by the disease, so work up to now has focused on oat and rye mixes.
“It would be interesting to try a more diverse cover crop mix, perhaps including a legume, such as red clover. But the unknown is how these other species may act as an alternative host for verticillium wilt.”
It is hoped that a separate Innovative Farmers project, looking at controlling two spotted spider mite with predatory insects, might shed more light on such risks. This ongoing work aims to create more favourable habitats for natural predators, such as Amblyseius andersoni and Amblyseius cucumeris, by establishing cover crops in the alleyways of the hop garden. Mixes could include broad leaf species potentially providing useful information that overlaps with the understanding of how cover crop species influence verticillium wilt risk.
Elsewhere, Hutchinsons is working with a vineyard in the West to see if microclover can be used as a living mulch, for weed suppression, biodiversity and soil health. In vineyards, living mulches could offer added benefits from shading the soil, and reducing soil temperatures in extreme summer heat; benefitting soil organisms and reducing vine stress.
Microclover’s short, stunted growth habit is potentially well suited to the role, as it minimises competition, allows good airflow around vines, and facilitates bunch ripening later in the season. As a legume it also fixes some atmospheric nitrogen to the soil.
“But one issue with legumes is that unless you terminate them, they don’t really volunteer to share that much nitrogen,” notes Mr Saunders.
Another vineyard Mr Saunders works with has sustainable practices at the core of its business, and is borrowing insights from the regenerative agriculture community, developing new approaches to managing cover crops in vineyards that might better utilise the benefits from leguminous species.
They are investigating whether one solution is to establish alternate rows of legume and cereal cover crops. The thinking is that by terminating the legume cover, before sowing it with a cereal, and vice versa, it may be possible to provide a continuous supply of nitrogen to adjacent vines, as well as carbohydrate to support soil biology, from decomposing legume roots.
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