How pigs can compost manure on a farm scale, saving you fuel and money

Farmer, Rebecca Hosking, takes a trip to a biodynamic farm in Cornwall to find out how they use Joel Salatin’s method of composting with pigs, rather than diesel, to turn their cow manure into fertiliser. These are pioneering farming techniques in the UK

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I’m sure many are familiar with this scenario: you’re driving along in the countryside and you’re suddenly hit with the overwhelming stench of manure from a farm. A dilemma ensues do you A) wind up your window to stop any more of the smell entering the car thus trapping the low level smell that’s already made it in; or do you B) keep the window down, taking on the full brunt in the hope the smell will quickly pass and fresh air will blow the rest of it away.

Muck-spreading.img_assist_custom-200x133When this happens to us (we’re windows open people) we usually comment – ‘That farm is wasting money’.

What we’re all actually smelling is a combination of Ammonia (NH3), Sulfur Dioxide (SO2), Hydrogen Sulfide (H2S) Nitric oxide (NO) and numerous volatile organic compounds (VOCs). Mixed in with those pungent gases are their odorless greenhouse bedfellows, nitrogen dioxide (NO2), Carbon dioxide (CO2) and methane (CH4).

Whether the smell from the farm is emanating from a yard dung heap, a slurry pit, a shed full of manure from over-wintered cattle or the muck spreader spattering its way across the field… it is the aroma of valuable nutrients fizzing off into the atmosphere where they do considerably more damage than good. Nearly all of these smells are the result of anaerobic decomposition – or as it’s known to the gardener, poor composting.

Now not all farmers are die hard environmentalists and some may even doubt the science behind global warming. All of them, however, are concerned with making ends meet and, as such, the escape of these gasses (particularly the nitrogenous ones) from the farm, where they will fertilize nothing but the nostrils of passers-by, must be a concern. If half the nitrogen in your farmyard manure wafts off over the M5 corridor and beyond then you have to pay good money to replace it to keep the farm productive. And with synthetic nitrogen fertilizer currently trading around £350/tonne, the cost soon adds up.

Gardeners have long known the best way to lock down nitrogen in manure is to compost it; and the best way to do that is to physically turn the material to aerate it. Many studies have trialed alternative methods but as yet nothing beats brute intervention. In all fairness, on a garden scale even we’ve found this is relatively easy to achieve, all you need is a sturdy fork, a bit of elbow grease, cups of tea and biccies.

However if I walk into one of our cattle sheds where the stock has been wintered for three months, the volume of dung to turn and aerate becomes an overwhelming challenge. Could it be possible with human labour? Well, nobody in their right mind would willingly volunteer for this job, no farmer could afford to pay for the necessary workforce and we abolished slavery in England back in 1772 (thankfully), …so no, it’s not an option.


Instead immediate thoughts turn to diesel powered machinery, much work with a front-end loader and investing in a trailer-operated compost turner. This is farmer speak for a lot of money, time, effort and fuel; making it an expensive exercise to even contemplate.

But what if there is another way, which is fraction of the price, requires no manual labor, no fossil fuel and no new farm machinery?

Enter Pigs:  Stage Right

I first became aware about using pigs for this job back in 2007 while reading about holistic farmer – and a bit of a visionary – Joel Salatin. I’m sure many of you will already be aware of his work.

Joel and his family run Polyface Farm in West Virginia. He openly admits they stumbled backwards into pig rearing. Initially they purchased just a few pigs to use as a cost saving device to aerate the farm’s cattle dung into compost. Polyface’s ‘pigaerator pork’ as the Salatins named it is now one of their most popular products.

Since then I’ve heard a lot about the theory of pigaeration and we’ve longed to trial it here, but the older generation on this farm, namely my father and uncle, don’t like change – I think I may have mentioned this before in previous posts! Anyway, in addition they have an irrational dislike of pigs so it’s not going to happen here anytime soon. However, luckily this year our friends decided to test it out on their farm so finally I got to witness it in action.

lozz-and-Jim.issueLaura and Jim Wallwork manage Tregillis, an organic, biodynamic farm at South Petherwin in Cornwall. As I’ve often joked with Laura, I’m happy keeping an open mind but still struggle with cow horns acting as cosmic antennae but, when it come to soil health, we could all learn an awful lot from the biodynamicists. At Tregillis, soil health and condition is a priority, hence their interest in composting dung on a large scale. Last week I popped down to see them and their pigs at work and Laura kindly walked me through what had been happening.

Laura has used Salatin’s approach as a template but has adapted the materials and ingredients to suit the particulars of her own farm. For the composting to be successful and the pigs to be agreeable, the preparation began right back at the beginning of December as the cattle first entered the shed.

Each day while bedding up the stock with fresh oat straw, Laura liberally sprinkled their own grown polycrop of peas, triticale and oats in amongst the bedding.

This differs slightly from Salatin’s original ingredients of woodchip as bedding and corn (maize) as feed. However, whether you use peas or maize, the results are the same. The dry food gets stomped into the bedding by the cattle, where it ferments in the compacted anaerobic dung and urine. The result at the end of winter is thousands of little, sweet, mildly alcoholic piggy treats tantalizingly hidden in a barn full of manure.






With the arrival of Spring, the cattle go back out onto the pasture and the pigs are let in to commence their own version of a giant Easter egg hunt.

By the time I’d arrived the pigs had been at it for a week and had made short work of turning and ploughing the dung back and forth whilst snuffling through the deep litter. It was a joy to see such happy pigs – stimulated, entertained and getting plenty of exercise – a far cry from any intensive pig system.

The next sense that struck me was the agreeable smell. Gone was the all too familiar aroma of cow urea that catches the back of your throat; instead a far milder, sweeter fragrance. Not quite forest floor but closer to that than the smell of raw slurry.

Finally I noticed the texture of the litter was completely different to what I’d expect to see in a used cattle barn. It was far drier with more noticeable brittle and broken up straw. As a comparison, a clod of dung of the same age from one of our barns could knock someone unconscious at twenty yards whereas the stuff from Tregillis would scatter in the spring breeze before it even reached its target.

Adding seaweed

dried-seaweed.img_assist_custom-200x133Laura has come up with her own addition of heartily broadcasting dried seaweed across the bedding; if this works then it’s a smart move. UK soils, owing to thousands of years of agricultural pounding, are mineral poor. Livestock farmers heavily rely on bought in mineral/salt licks to supplement their animals’ dietary needs and cattle get through these licks like…well…a dose of salts.

The licks are expensive and completely unsustainable so by adding the dried seaweed to the bedding Laura hopes to boost her pasture’s mineral content when applying this rich compost later in the year.

In a further Tregillis enhancement, Laura has also been adding a biodynamic herbal preparation to improve the composting process and final result. Like many things biodynamic, I don’t think anyone really knows exactly how it works but it does. As the late ecologist, Frank Egler, said “Nature is not more complicated than we think; nature is more complicated than we can think” and that certainly applies to compost. The trillions upon trillions of births, deaths, rebirths, predations, consumptions, emissions, absorptions, assimilations and reactions that occur to create healthy nourishing compost really is beyond comprehension

So were Laura and Jim happy with the results? …yes and no.

Laura pointed to parts of the bedding that were still wet and to the very bottom layer of dung that the pigs had not touched but she knew exactly where they’d gone wrong. By not spreading the food evenly and not putting a thick layer down first at the beginning of December before bedding up with straw had meant the pigs were not interested in those areas. Pigs are very much led by their snouts so no food means no aerating but it’s something they can easily correct next winter.

Over all though Laura is pleased with the pigs’ efforts. The compost/dung will next be taken out of the shed, covered and left to cure for a good few months before being spread on Tregillis pastures.

before-and-after-shot.img_assist_custom-399x205As for the pigs, well to paraphrase Joel Salatin, “They are farm machinery that never needs an oil change, they appreciate over time; and when you’re done with them, you can either breed from them, sell them, or eat them.” This year, Laura and Jim have a load of lovely sausages in the freezer.

Rebecca Hosking and Tim Green made the BBC2 film, ‘A Farm For a Future’ which explored peak oil and climate change in relation to farming. Whilst researching, they discovered permaculture and decided to return to the small mixed farm that Rebecca grew up on in Devon, help with day to day tasks and experiment with some cutting edge ideas and techniques. They regularly report the results for Permaculture online.

Useful Resources

How to build a pig enclosure from pallets

Joel Salatin’s pattern for carbon farming at Polyface Farm

Heating a greenhouse with compost and manure

Want to find out more? SUBSCRIBE to Permaculture magazine and get a quarterly dose of practical inspiration. Or download a FREE sample issue and try before you buy. Also available as a digital subscription (for just £10) and Apple and Android devices. 

More from Rebecca and Tim

‘A Farm for the Future’ – the full length film on peak oil, farming and permaculture

‘Earth’ – so important they named a planet after it ( and how to build hugel beds)

Fossil fuel fertilizers vs compost teas on the farm

Farming for the future – despite what the neighbours think

How to design more resilient, food producing systems (without money and fossil fuels)


Help spread the permaculture word….

Intensive Beekeeping Seminar & Workshop

29-30 March, 2014


During these intensive 2 days you will focus on the analysis of changes that have affected beekeeping in Cyprus in the past 35 years and their impact, as well as how best to proceed with regards to sustainable beekeeping.  The course will cover the best frames and hives to use for bees, the use of drugs and their influence in honey quality, how to recover colonies and how best to manage them, how to deal with climate change and how to improve the quality of your honey.  Time will be spent both inside the classroom and outside inspecting the 10 hives already functioning at Atsas farm.

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Connecting the Dots: the Big Permaculture Picture

Jeremy Wickremer explains why he believes permaculture offers multiple answers to societal and environmental problems in a beautifully simple and effective way.

Photo © Craig Mackintosh (

The solutions to our current social, economic and environmental challenges can be split into two distinct categories, the ones that are zoomed in on specifics and those that are zoomed out looking at the bigger picture. As an example, if you were only zoomed in on the specifics you might take up jogging to improve your health, but pause every now and again for the brief ‘pleasure’ of a cigarette.

But by zooming out even a little bit, just enough to connect the dots, it can easily be seen that the two behaviours conflict with each other – like having a tug of war. Just as conflicted behaviour and short-term thinking on a personal level leads to distress, conflicted behaviour at a societal level leads to distressing results for society and also our natural world.

If we want to find effective solutions for a better way to live, it means connecting the dots between interrelated problems. Just like you need a holistic vision for a healthy mind and body, the same applies for a healthy planet.

One way of living that seeks to do this is permaculture. To put it simply, permaculture is a design system that mimics nature, where everything in the design supports everything else to produce sustainably. The core principles are; caring for the earth, caring for people, and sharing any surpluses with others. It encompasses growing food, sustainable housing, water harvesting, eliminating waste, renewable energy, agroforestry, animal management, finance, building community and earth repair.

By connecting the dots and thinking sustainably permaculture is an antidote to the giant global game of tug of war that goes on around the planet, with each other and with the planet’s natural resources. Permaculture effectively looks to connect all the different parts of the ecosystem finding solutions where one person winning means everyone wins and the planet wins too.

“Because permaculture is a toolkit for designing low carbon systems and not one method or technique, we can find practitioners working in as many niches as we can perhaps imagine.

There are hill farmers in Britain using permaculture to design more financially and ecologically diverse livelihoods; agro-ecologists in the Amazon planting forest systems for food, medicines and timber that are more biodiverse than surrounding rainforest fragments; urban projects in big cities involving community gardening on abandoned land and rooftops; smallholders the world over with mixed farms combining animals, annuals and perennial crops for food security; even low carbon enterprises that use permaculture principles to design ‘invisible’ structures.

What characterises all of these is the uptake of core ideas like mimicking natural systems, cycling energy, using and valuing the edges and the marginal, enhancing biodiversity and using renewables….. Permaculture is all about using common sense and applied ecology.” Maddy Harland, Editor of Permaculture Magazine.

Around the world permaculture projects are helping people connect with the land and source of their food; in addition it can play a vital role in ecological restoration. Witness initiatives such as the Water Retention Landscape of Tamera in Portugal and Greening the Desert in Jordan documented by film maker John D. Liu.

In London’s Lea Valley, a community food project, Organiclea has been growing food for over 10 years. In 2009, volunteers and friends took over the local council’s abandoned nursery, a 12 acre site with extensive glasshouses, scrubland and woodland edge on the outskirts of London.

A year of observation, mapping, trials and permaculture design helped to turn the site over to the production of a wide range of fruit, salad leaves, vegetables and herbs, with 4 acres of market garden, a forest garden, fruit orchards and a vineyard. Now food grown with high standards of sustainability, using organic and permaculture principles, is distributed by bicycle and electric milkfloat via a box scheme to homes, local market stalls, restaurants and cafes.

Resurgence & Ecologist magazine’s Satish Kumar has a two acre farm in Devon, UK where he integrates permaculture design and grows 80% of his food. He has also established a school for 11-16 year olds where, as well as the traditional subjects, every child learns to grow and cook their own food. Satish says:

“The permaculture garden is the best classroom for biology, for chemistry, for physics, for poetry, for economics, for politics. Every subject you can learn in the garden…permaculture is one of the most beautiful and perfect models for resilient, sustainable, ecological and joyful ways of life.”

You can view a clip from an interview with Satish Kumar on permaculture here. The full interview will be streamed on Grow Local Live!, a 24 hour webcast of events, reports and interviews from the global permaculture community for International Permaculture Day on May 5th. The programme will include leading permaculture designers David Holmgren, Dave Jacke and Geoff Lawton, and feature bioneers such as Vandana Shiva, Rob Hopkins, Helena Norberg-Hodge and Charles Eisenstein.

Take a look at the International Permaculture Day’s website for a whole host of events going on around the world:

Jeremy Wickremer, Transformational Media Initiative


Soil Biology Principles, Compost & Natural Fertilizers: 2 Day Intensive Workshop 21-22/09/13

This 2 day intensive workshop is designed to give you a genuine understanding of soil management, how to increase your top soil and improve production.  Participants will acquire the practical experience of how to grow, manage, and apply beneficial microbes as high value compost and compost tea.  The complex science of soil biology will be presented in an easily understood format so that farmers can embrace and achieve sustainability and profitability.

Making compost at Atsas Organic Farm

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Joel Salatin’s pattern for carbon farming at Polyface Farm

Maddy meets Joel Salatin and hears how Polyface Farm has restored the soil, locked up carbon and makes a healthy profit for all its micro-enterprises. Salatin-style farming is cool!


Joel Salatin (left) with Aranya

Joel Salatin, dubbed by TIME magazine to be the world’s most innovative farmer, hit town yesterday and Aranya, who wrote our bestseller, Permaculture Design Step By Step, and runs RegenAg in the UK, invited me along to a one-day seminar hosted at Cowdray Hall in Sussex to learn more. I have long wanted to meet Joel, having heard about his work from Rebecca Hosking and others and watched YouTubes about his methods. I wasn’t disappointed.