Following on from a previous post ‘in defence of annual vegetables,’ where both the limits and potential of annual horticulture were explored, this writing aims to turn attention to the pioneering solutions and alternatives. The cultivation and domestication of annual crops is over 10,000 years old, and has marked the dawns and dusks of human civilisation. It was through annual cultivation of plants/crops that encouraged previously nomadic humans to settle, originally in Mesopotamia, the Fertile Crescent - now a dustbowl largely due to over-reliance on annual and monocultural production (Hyams 1992).
Accelerated in the last century, our food systems have since been ever more reliant on annual, commodity-based and monocultural cropping, requiring the yearly cultivation of land, tillage, high inputs, often chemicals and fertilisers, all the while our soil has deteriorated alongside the biosphere and its beings. This has led to the perfect storm of biodiversity loss, spiralling climate chance, topsoil loss and many forms of pollution, not to mention the erosion of rural culture, indigenous lands and wild places. All in the name of feeding a world population which will no longer be able to inhabit these degraded lands if we continue business as usual. There has never been a time more urgent to re-assess our food system on multiple levels, and this requires weaving together many promising parts of the active solutions – one of which being perennial crops.
A shift towards perennial agriculture represents the transformation of our culture towards greater permanence, regeneration and rootedness, as many perennial plants model so well for us. Perennial crops grow back every year from the same root systems, deepening their relationships over time, giving more each year, following seasonal rhythms of the Earth and providing a range of ecosystem regeneration services. These crops, including tree crops (e.g. hazelnuts, apples), shrubs (e.g. berries, herbs) and perennial plants (e.g. asparagus, perennial leek, kale), are better for personal, planetary and soil health. And yet the vast majority of our diets rely on non-sustainable annual crops, and our food systems battle with nature to take out and replant these every year in vast monocultures. To be clear, annual crops can be done well, and they have their place in our landscapes and diets, just as you would see annual plants in a healthy native forest. But their benefits, like many organisms, are only realised in relationship and collaboration, in an ecosystem of diverse plants, perennials and a healthy soil food web. To integrate these commons sense biomimetic lessons and bridge the ideals with today’s landscape, it is important to find a pragmatic way to cultivate perennial crops in a commercially viable way.
Below is an overview of integrating perennials and their key benefits, with some examples and suggestions of how to integrate effectively and ecologically within our food systems.
Perennial crops are those that grow without the need for annual cultivation and planting. This includes many high value and nutritious vegetable, herb, fruit and berry crops that can be grown with fewer inputs and less labour than many needy annual crops. Perennials can be incorporated into a horticultural system even on marginal pockets of land whilst regenerating the ecology and economics of a farm enterprise (Shepard 2013). Perennial crops are an emerging market opportunity to sell to restaurants, wholesale and direct to consumer.
Perennials can increase the overall resilience and viability of a farm whilst relying on fewer inputs of time and energy in the long term
Perennial Vegetables represent up to 56% of vegetable species and yet only occupy 6% of horticultural cropland. These species also contain higher nutrient levels, often crop during the UK 'hungry gap' and offer greater climate resilience (Toensmeier 2020). Many perennials will crop for 8 or more years after planting in contrast to annual crop cycles. This allows for undisturbed root development and increased mycorrhizal activity in a thriving soil food web. Perennial cropping systems sequester and store more carbon due to their deeper roots, permanence in the ground, minimal disturbance and continual cover of the soil, aligning with many regenerative agricultural principles (Shepard 2013).
Image 3.1 Asparagus growing between perennial nuts and berries, New Forest Farm 2011
The resulting decrease in soil-erosion, nutrient leaching and fertility (income) loss is significant. Perennial crops also increase biodiversity, hosting insects, pollinators and natural predators to allow for a thriving farm ecosystem and integrated pest management (Toensmeier 2007). Many perennials also add to fertility cycles by providing
plant biomass, leaf mulch and ramial Woodchip (Raskin 2019). Perennial agriculture has not yet been widely
adopted in the UK due to economic barriers to start-up costs., delayed income during establishment,
consumer habits and lack of case studies. However, these barriers are shifting and the converging social, economic and climate contexts are pointing towards a perennial revolution in agriculture.
CASE STUDY - NEW FOREST FARM
Agriculture and horticulture have been dominated by annual crops in the age of cheap fuel and industrial 'productivity', so there are relatively few examples of diverse perennial farms at scale. However, it is increasingly clear and evidenced that perennials can be integrated successfully at a range of scales, from Martin Crawford's Forest Garden approach on 2.5 acres, to Mark Shephards Restoration Agriculture approach on 106 acres. The land is incredibly diverse and yet requires few inputs. Taking a single acre, Shepard produces 2400kg of chestnuts (£48,000 revenue at £20/kg) 3200kg of red currants (£33,600), 900kg asparagus (£16,200) with two cattle, four hogs & 10 turkeys to manage the land and its cycles (Shepard 2013). The majority of labour time in a perennial system is in appropriate design and year 1 establishment, and then harvesting in later years which brings in a high income and supports many livelihoods.
Image 3.2 Perennials at Mark Shepard's 106 acre 'restoration farm' (2013)
EXAMPLES OF MEASURING IMPACT:
· Soil health and stabilisation through observed decrease in run-off and soil health indicators e.g. from samples sent to Soil Ecology Lab
· Carbon sequestration (e.g. measured using Farm Carbon Toolkit),
· Biodiversity Net Gains & ecological surveying
· Diverse and regenerative income streams
· Additional ‘bonus’ income from perennial crops on marginal or shaded land. improvements to the small water cycle, measured by water tests, observed water capture and infiltration
COSTS & ESTABLISHMENT
Many Perennial crops are in the ground at least 2 years before cropping, which prevents many growers from investing in them. Gradual transition from annuals and use of quicker perennials e.g. strawberries can buffer this risk.
Keyline water management recommended but not essential on all sites, costing approximately £1450 per hectare to establish. Electric or permanent fencing for deer, rabbit and badgers advised, costing approx £9/metre
Perennial crops vary in establishment costs. Taking Asparagus as a high cost, high yield example: establishment costs of £7900 per hectare with 16 labour days and 2 days tractor disc cultivation
cropping by year 3 with yields of 3145kg , with market price at £18/kg generating revenue of £56,610 / hectare (figures from Welsh Gov 2021).
Perennial crop integration is suitable on a range of soil types, slopes and climates. Generally well draining sandy-loam soil is ideal, but many varieties will thrive on clay-loam and silty soils with some organic matter (e.g. compost) and mycorrhizae additions at planting.
Many perennials such as berries and herbs can grow well in partial shade so are appropriate on less sunny land sites.
Some wind protection will benefit early growth and establishmen, but staking and deep planting can be used to mitigate this.
As a long term crop, perennials are not so suitable on short term or insecure land tenure, development land or land vulnerable to climate extremes (e.g. flooding).
Economically, if a farm business doesn't have the cashflow to free up annual cropping space, interim funding and support will be required.
Accessibility to markets for niche perennial crops is essential to plan before starting; a growing but small market and suitable context would include pre-existing wholesale relationships, existing CSA scheme and peri-urban areas.
Further reading and sources:
Crawford, M., 2012. How to grow perennial vegetables. Green books.
Hyams, E., 1952. Soil and civilisation. Thames & Hudson. Shepard, M., 2013. Restoration agriculture (No. 631.584 S547r). Texas, US: Acres,. Toensmeier, E., 2007. Perennial Vegetables: From Artichokes to Zuiki Taro, A Gardener's Guide to Over 100 Delicious and Easy to Grow Edibles. Chelsea Green Publishing. Toensmeier, E., 2020. Perennial vegetables: A neglected resource for biodiversity, carbon sequestration, and nutrition. PLoS One, 15(7), p.e0234611. Welsh Government, 2021. An examination of the practical and financial potential for growing small scale asparagus organically at 2 locations in South Wales. Full online research report: https://businesswales.gov.wales/farmingconnect/sites/farmingconnect/files/documents/Asparagus% 20Final%20report.pdf Image 3.1 : Asparagus, Bedlam Farms https://wickedleeks.riverford.co.uk/opinion/perennial-trial-and- error/ Image 3.2: New Forest Farm 2011 https://newforestfarm.us