Why Cover Crops are Important in Regenerative Farming
“Farming is an essential industry without which human life could not be sustained. But it can also be ecologically destructive if not done right. Regenerative farming aims to offset negative ecological impacts by shifting away from outdated and damaging farming techniques in favour of conservation, restoration, ecological stability, and sustainable food production” (Newton et al, 2020[KJ1] ).
What is cover cropping?
Maintaining and preserving healthy soils is paramount to regenerative farming. Traditional intensive crop rotation and over-cultivation in summer, followed by periods of bare earth during a fallow period, can harm soil quality. This cycle damages soil structure, nutrient content, and fertility. Bare ground also severely diminishes soil biology and its viability to sustain future crops. Cover cropping is a technique which actively reverses centuries of soil destruction by planting out empty fields with non-food crops in between cash crop seasons (ADHB, 2015).
So what are the benefits of cover cropping and how does it work?
Improves fertility - When it’s time to sow cash crops the cover crops are converted into organic fertiliser. Cut down and left on the surface of the soil, they break down into a nutritious, organic mulch known as ‘green manure’ to sustain next year's cash crop (AHDB, 2015). For example, plants such as Clovers and Brassicas absorb high amounts of nitrogen which is then released back into the soil (Clark, 2018). This reduces the need for excessive chemical fertilisers that can severely damage soil viability over time (Schiffman, 2017).
Prevents erosion and improves structure - Cover crops protect exposed soils from the elements. Strong winds and rain runoff can displace soil, whilst heavy raindrops or snowfall can compact it, compromising its structure. Grasses such as Wheat have extensive fibrous root systems that prevent compaction below ground whilst creating a barrier to the elements above ground (Cherlinka, 2020). Crops such as Legumes have strong, deep taproots that loosen compacted soil in place of excessive mechanical tillage, improving drainage, particularly in heavy clay soils (AHDB, 2015., Clark, 2018). Crops like Fodder Radish generate high biomass, increasing the amount of beneficial organic matter in the soil (Scottish Government, 2015). This both aids drainage and aeration, but also attracts beneficial organisms whose presence further improves soil structure and health (Clark, 2015).
Controls weeds - Fast-growing cover crops outcompete weeds for sunlight and nutrients, whilst crops like Rye release chemicals which naturally inhibit weed germination (Wilson, 2012). Cover crop mulch further suppresses weeds from taking hold after cash crops are sown. This reduces the need for indiscriminate chemical herbicides that can inadvertently kill nearby fauna, damaging valuable habitats and food sources for wildlife (Jenkins, 2018).
Improves biodiversity and deters pests - Repeatedly cultivating the same cash crops each year creates a loss of biodiversity. Using a varied mix of flowering cover crops such as Flax or Sunflower will attract a diverse range of pollinators and help to conserve native ecosystems (Anon, 2017). They will also attract beneficial creatures who prey on crop pests, acting as biological pest control and reducing the need for chemical pesticides which have catastrophic effects on the wider ecosystem (Wilson, 2012).
Improves soil health – The cover crop provides a continuation of the soil – plant relationship allowing the soil biology to continue to thrive. It also provides shade to the soil protecting the upper layers of soil from getting too hot for the microbes and other soil organisms to survive. As the cover crop dies off the roots add essential levels or carbon to the soil that help hold moisture for the coming cash crop.
Anon. (2017). ‘Habitat Highlight: Flowering Cover Crops’. Xerces Society for Invertebrate Conservation. Available at: https://beebettercertified.org/habitat-highlight-flowering-cover-crops/ (Accessed 29th September 2022).
Agriculture and Horticulture Development Board. (2015). ‘Opportunities for cover crops in conventional arable rotations’. AHDB. Available at: https://projectblue.blob.core.windows.net/media/Default/Imported%20Publication%20Docs/IS41%20Opportunities%20for%20cover%20crops%20in%20conventional%20arable-rotations%20(2018).pdf (Accessed 28th September, 2022).
Cherlinka, V. (2020). ‘Cover Crops: Types And Benefits To Use In Agriculture’. EOS Data Analytics. Available at: https://eos.com/blog/cover-crops/ (Accessed 29th September 2022).
Clark, A. (2015). ’10 Ways Cover Crops Enhance Soil Health’. Sustainable Agriculture Research and Education. Available at: https://www.sare.org/publications/cover-crops/ecosystem-services/10-ways-cover-crops-enhance-soil-health/ (Accessed 28th September, 2022).
Clark, A. (2018). ‘How to pick the right cover crop mix this autumn’. Farmers Weekly. Available at: https://www.fwi.co.uk/arable/land-preparation/cover-crops/pick-right-cover-crop-mix-autumn (Accessed 28th September 2022).
Jenkins, R. (2018). ‘What Are Herbicides? Herbicide Pros & Cons’. ABC Blog. Available at: https://www.abchomeandcommercial.com/blog/herbicide-pros-cons/ (Accessed 29th September 2022).
Newton, P., Civita, N., Frankel-Goldwater, L., Bartel, K., and Johns, C. (2020) What Is Regenerative Agriculture? A Review of Scholar and Practitioner Definitions Based on Processes and Outcomes. Front. Sustain. Food Syst. 4:577723. doi: 10.3389/fsufs.2020.577723
Schiffman, R. (2017). ‘Why It’s Time to Stop Punishing Our Soils with Fertilizers’. Yale School of the Environment. Available at: https://e360.yale.edu/features/why-its-time-to-stop-punishing-our-soils-with-fertilizers-and-chemicals (Accessed 28th September, 2022).
Scottish Government. (2015). ‘Use of Cover Crops Practical Guide’. Farming for a Better Climate. Available at: https://www.fas.scot/downloads/practical-guide-use-of-cover-crops/ (Accessed 29th September 2022).
Wilson, W. (2012). ‘Cover crops: What are the benefits?’. Farmers Weekly. Available at: https://www.fwi.co.uk/arable/cover-crops-what-are-the-benefits (Accessed 29th September 2022).
[KJ1]If you want to include the entire quote verbatim change the font or italicize it so it’s clear it’s a quote. I think its dangerous to poke this “destructive” finger at people we want onside. So we have to be carful how to use it.