After the rain — How to get more forage from your pasture

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This is a guest post by Niels Corfield, soil health, agroforestry and whole farm planning advisor, researcher and advocate. You can find more articles from him on medium.

What can we do to capitalise on rain when it comes; so we can get more forage and improve the health of our pasture and animals? I’m going to present some observations from pastures around the UK. Along with what I feel are the key opportunities available to graziers (in the West at least).

Key Observations
Below are 2 pics of the same spot in a permanent pasture. What is a fairly typical situation. What can we glean from them?

Firstly, and most importantly, there are clear bare patches. There could be as much as 50% bare soil, in this case.

These images are following a grazing event (in this case rotational grazing). This type of situation may well be similar to what is revealed after a hay cut, although in this case a low “sward density” maybe a more representative way to quantify the amount of bare soil, since much of the soil after a hay cut will be covered with residues (which is good but is only short term) and otherwise covered by leaves, though still open at the base — leaving space (bare soil) between the plants.

Bare patches in the pasture (as in all soils) are a weakness since it’s a place where water and carbon are lost, and soil health is declining. But they may also be an opportunity.

Ideally, there is no bare soil in pasture, it being covered by living plants, a tight/dense sward, with a closed canopy.

See here for details on recording bare soil in pasture.

Ideally these areas are covered with residues (litter or mulch). In a grazing situation, this would be the product of high stock density grazing management, where low utilisation rates leave residuals that are trampled on to the soil surface, see brief discussion on this topic in earlier article here.

A more ideal solution to this is to have a dense sward with leaves and turf tight enough that it forms a closed canopy that covers the soil surface.

We’ll focus on this second approach and see about turning this problem into a solution.

Selecting Options

Establishing seed into existing leys or pasture is notoriously tricky. In this piece I will not focus on the nuance of this process. Except to say that when selecting methods available to you, whether through contract work or doing it your selves, those options that score higher on the soil health principles should be preferred, see above. With obviously the plough down reseeding scoring pretty low.

A few of the standard methods are outlined below:

Ensuring Good Establishment

Broadcast Overseeding
In this case, where we have a high degree of bare soil, broadcasting is an option that is highly indicated. Basically, spinning-on a mixture of seed. Though slot seeding is still a good option, see below. Where considering broadcasting, there are a few things to bear in mind to get a good take:

1.Improve seed-to-soil contact by rolling or trampling
Cambridge rollers, cultipackers etc are suitable for this purpose as well as, grazing livestock at high stock densities — 100,000+kg live weight/ha, for a day or less (aka mob grazing) after broadcasting. Both these practices could be combined with mulching, or bale grazing, see below.

2.Retain soil moisture by covering soil
Even when there has been a lot of rain, it’s still a good idea to maintain that soil moisture, to improve the take.
Do this by spreading loose materials like straw, woodchip etc. To mulch the soil and keep the soil surface damp.
See pics below for illustration. And further discussion in mob grazing section at foot of earlier piece here.

3.Offer fodders in the field (while still moving the animals)
There’s a few different ways to cut this. But basically keeping the animals in the field and keeping them moving, ideally in tight groups, will aid the process of seed establishment. Different options include: bale grazing and green hay strewing.

Both methods mean being able to keep the animals in the field (when there’s insufficient forage left) and, particularly when combined with high stock density grazing they are ways to:

– tread-in seed — see point 1, above
– dung and urine densely — seeds will grow under pats
– provide some residues to cover seeds and retain moisture
– introduce perennial pasture seeds back into the pasture

In fact these solutions provide most of the functions required to achieve good take: seed contact, covered soil, seeds.
While also keeping animals out in the field, removing the need for muck handling in the yard. And providing better conditions for animals, than indoors.

Legume seedlings germinating in manure pile

Slot Seeding
Another option for establishing seed into pasture, perhaps where bare soil is less prevalent, and the appropriate kit is available, is slot seeding.
Drilling, rather than broadcasting means the seed will have the better seed-to-soil contact. It will also be placed below the surface where the soil moisture will be higher, at least nominally.
It is certainly more frugal with seed.
Perhaps the main drawback with this option, is that in these very dry conditions it may be difficult to penetrate the soil surface.
Either way, where the kit is available, this method is perhaps the most robust and economic — when it comes to seed, at least.

What Seeds to Sow

Making Initial Selections
We’ve talked about establishment options. So what’s the best seed to actually sow in the pasture? Given that we have run out of forage (due to a lack of regrowth) and we have a degree of dormancy in our pastures.
What might our selection criteria be for selecting plant species:

  1. Fast growth — forage available this season
  2. Bulk — lot’s of dry matter to make up for the short-fall
  3. Nutritious — ensuring sufficient animal performance

So, what type of plants meet these criteria?
Annuals, diverse mixes of them.

Why Annuals, What’s Wrong with Pasture Grasses etc?
Well in a word growth rate — annuals need to complete their lifecycle in a year or less (so it’s a sprint race for them), in that time they can grow tall and produce a lot of bulk and their seed is cheap. You might even have some in the shed right now.
In this case particularly, as a way to get an early bite, and to beat the season, they are highly indicated.
Coupled with that the option to use warm season species (those adapted for hot dry conditions) they’re doubly indicated.

How to get the best return on investment? Sow mixes of annuals.

Compared to this pasture species are perennials, they are: generally slower growing, slower to establish and typically much smaller plants (adapted for multiple grazing events in one season). This is all related to their life cycle of multiple year.
It’s not to say that they can’t be included in a seed mix for sowing now, but with annuals. There’s also the small consideration of seed cost. And grass seeds are on the upper end, needing to be purchased from specialists seed merchants. Another indication for hay strewing or bale grazing.

Principles of Diversity & Soil Health
One of the most important of the soil health principles is diversity. The key insight being that a diversity of plants feeds a diversity of organisms. This diversity is regarded as the key to soil organic matter formation and to a balanced diet for plants, as each organism has it’s own nutrient mineralising specialisms. Ensuring a better diet for animals.
Diversity is also correlated with increased yield.
This is where cover crops and pasture species, being mixes, really excel, compared to crops which have their own restrictions, tending to monocrops.
Once you add-in annuals into the mix, alongside perennials, you really can push the diversity lever up to 11!
Experience has also shown pasture cropping examples, like this, that have resulted in step-changes in soil aggregation, with all those extra living roots pumping-out exudates into the pasture.

Diversity in Action
When it comes to diversity, how much is enough? And what should you choose? Given there’s so much choice.
Thankfully there’s some simple rules, we have been offered from US practitioners, that we can follow:

  1. 8x species (or more) is a sweet spot, for soil health benefits, from
  2. 3 out of 4 functional groups

Functional Groups
What are these functional groups, and why are they important?
Well they give us some pointers as well as narrowing-down the options somewhat. They are:

  • Warm season grasses
  • Cool season grasses
  • Warm season broadleaves
  • Cool season broadleaves

Perhaps this seems like an odd list. And why choose warm season plants for instance?
Well, the first reason is they can actually grow really fast. Due to the fact they photosynthesise using different frequencies of light, more prevalent in strong sun situations. This is why maize is such a high yielding crop, growing to 7′ in a season. These plants are also known as C4 plants.
The other reason we’d select them, in this particular case is due to the fact that we are actually in a warm season, right now. And our pastures (which are all cool season species) have gone dormant or “burned off” because of the extended dry spell. Warm season plants are adapted for these conditions, and have the ability to grow through the “summer slump”. Though establishment is certainly still an issue.

The Specifics
Below is a table of the main species of cover crops.
Remember select 8 or more species from 3 or more of the functional groups.

There’s nothing to stop you using farm-saved seed: peas, oats, wheats etc.
The other option is to source bird seed mixes and feed cereals locally/in bulk. This will certainly bring down the cost, compared to a seed merchant.
In fact there’s a real advantage to doing this as it will allow you to up the seeding rate. If there’s one golden rule with cover crop establishment it’s:

Don’t skimp on seed, too little is as bad as no seed at all.

Putting It All Together

So what might a successful oversowing of annual-based forage mixes look like?
Some examples below. And a few new bits of jargon, all of which are relevant to this situation. Although the text mostly refers to a cropping situation, they are equally suited to pasture, when due diligence is followed around establishment. It’s clear to see that these mixes have the potential to produce large volumes of diverse (quality) forage in a short space of time.
Pasture stitching is the name given to drilling forage crops into pasture.

Final Thoughts

I hope that this piece offers some practical suggestions of what to do in droughted, burnt-off pasture or more generally in tired pasture, when you want to get a forage boost, or provide forage in the off-season, while improving soil health, and with it animal health — through better quality (diverse) forage.

Take Home Messages

  1. Use the soil health principles to inform your decisions and to direct your observations in pasture
  2. Cover bare soil by litter and living plants
  3. Choose rapid growing annual species for instant results
  4. Diverse plantings are preferred, where planting date is appropriate
  5. Keep costs down by: using your own seed/creative sourcing
  6. Experiment, try some different: mixes, seed rates, establishment methods

And for those that want to find out more, or discuss this in more detail please get in touch or consider joining me on one of my soils courses. If you have any thoughts or questions, get in touch: info@nielscorfield.com

Soil health courses & info
https://www.facebook.com/pg/nielscorfieldland/events/

Further Reading
Part 2 — Realising the Promise of Soil Health in Organic Horticulture
https://medium.com/@nielscorfield_90202/no-till-for-growers-realising-the-promise-of-soil-health-in-organic-horticulture-646fd553257

Don’t think you’ve got time to go out and dig holes? Think differently!

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What does the future hold for farming? Well, the truth is, we don’t have a crystal hoof! But, there is one way to make our farming enterprises resilient, through the wettest of winters and driest of summers. A way of reducing inputs, increasing biodiversity and building a healthy planet. Farming with a focus on regenerating our soils.

We all need to start somewhere on this journey. What does your soil structure look like? Is it compacted? Is your soil at risk of erosion? Is it alive with worms, microbes and fungi? These are the questions we should be asking ourselves as farmers today, and they can be answered by getting out into your fields and observing for yourself.

Whatever type of farm you are, whatever your location, you can benefit from soil monitoring. It is the basis for knowing if your soil is healthy or not and if it supports healthy crops and animals. Without knowing how healthy your soil is, how can you improve it?

Lab tests are only part of the picture, numbers on a page. Soil health analysis is visual, connecting you to your land, monitoring it’s pulse. It is your guide.

But what will you get from soil monitoring? (Apart from muddy fingernails!)

From your first set of tests you create a baseline of your soil health. Straight away you can draw insights from comparing soil test results on fields under different land use. But really the magic happens when you come back to the same sample spots and do these tests again, and again, and again.

Record observations, photograph what you find and save the GPS locations of your sample sites using the Sectormentor app. Next time you can return to the exact same spot on the map and compare it with the last time you were there. Worms love the camera!

Then you will learn if your cover crop roots are improving soil structure, or if your new grazing system is stimulating microbial life and so on. All this information is available to you through simple, low cost tests, and acts as your guide for how to improve your soil health.

Don’t think you’ve got time to go out and dig holes? Think differently!

To be successful at soil monitoring you need to build it into your routine. The first time is always the hardest and perhaps you have another more pressing task (like tidying the farm office!) BUT once you get going, you’ll be hooked.

Day-to-day farming activities you can do when you’re soil monitoring:

Checking livestock
Once you’ve made sure they are all there, no one has jumped the fence and the water trough isn’t overflowing why not fetch your spade, dig a hole and count earthworms? Manure from the beastys feeds dung beetles and worms, so you should find lots of activity.

Crop walking
Heading out to see what growth stage you’re at? This is the time to assess how well your soil is supporting your crops. Is there an area that doesn’t look so good? Perhaps there is a compaction issue, you’ll only know once you get the spade in and do a visual evaluation of soil structure.

Fencing
Need some light relief from moving electric wires or post bashing? It’s likely you’re in fields grazed by our furry and/or feathery friends. Check out the diversity of their forage by throwing a quadrat around and see how what’s growing affects soil biology by doing a slake score.

Taking the dog(s) for a W-A-L-K
We have it on good authority that dogs love to go soil testing, we’ve seen it with our own eyes. They will get a good leg stretch and tail wag as you tour the fields with your spade. They might even carry your quadrat for you.

..and remember, digging one hole is better than digging none. Just dig it!

 

Ready to get started soil monitoring? Check out Sectormentor for Soils – a handy smartphone app to record soil test results and photos in field and online account to analyse your observations.

How to store water in your soil and prevent erosion

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As the weather in the Northern Hemisphere gets rainier going into the Autumn months, the question of our soils’ relationship with water springs to mind. We know that healthy soils absorb much more water than unhealthy soils, and that healthy soil is less likely to degrade into runoff, but what’s the science behind this?

We’ve done some reading around the literature on this subject, to learn how to keep our soils in top shape with regenerative agriculture, and to build a greater resilience to climate extremes like flooding and droughts. 

First, leaving soils uncultivated has been shown to increase the structure of macroaggregates within the soil – many studies show an improved macroaggregate stability in soils under no-till compared with ploughed soil (1,2). This is because the net of undisturbed roots and mycorrhizal hyphae entangle smaller aggregates together, reducing the likelihood of soil runoff during heavy rain, and increasing porosity. You can easily assess the macroaggregate stability of your soil with the VESS test or the Slake test (and the results can then be recorded within our Sectormentor for Soils app!). Hopefully, having an awareness of how your soil scores on these tests will help you to understand how to improve your soil health! 

A long-term study found that conservation agriculture plots retained ⅓ more water under both wind and water erosion compared with conventionally tilled plots (3). Reducing wind and water runoff is significant – we know for example that the devastating US ‘Dust Bowl’ in the 1930s was caused by intensive cultivation, and hugely impacted food security at the time – it’s estimated that 300 million tonnes of topsoil was swept up by the wind, destroying crops and killing livestock (4). With extreme weather events increasing due to climate change, building soil resilience is of utmost importance.

In the same vein, agricultural runoff causes massive ecological damage, and is a major source of nonpoint source pollution in water systems – with runoff likely containing fertilisers, pesticides, nutrients and topsoil. A study comparing four streams with catchments from land under different management, found streams feeding from land under conservation agriculture had a higher diversity of invertebrates and more ‘clean water’ species than streams under tilled land, which was attributed to improved soil structure reducing agricultural runoff (5). The reduced topsoil runoff into nearby rivers and streams also reduces sedimentation, which increases the river’s capacity, as well as the clarity of the water – allowing sunlight to benefit the wildlife and photosynthesis in aquatic plants. Rivers with high sedimentation also absorb more heat from the sun, causing local warming which potentially causes further damage (6). 

Soil erosion in the UK is clearly visible from space. Credit: NEODAAS/University of Dundee

We loved seeing the rainfall simulator at Groundswell this year – it really helped us to visualise the ability of healthy soil to absorb rain! You can watch a video of a rainfall simulator in action here.

Rainfall simulator in action at the 2019 Groundswell show – the bottles on the ground show the water that filtered through the soil in each plot, while the hanging bottles show the ‘runoff’ water.

So, to wrap up, healthy soils absorb and hold more water than degraded soils, which helps to reduce flooding, aquatic pollution, and resistance to drought conditions and wind erosion! Keeping your soil optimally protected involves minimal disturbance, continuous cover with mulch and living roots, and root diversity (from crop diversity) allows for increased microbial populations which help to aggregate soil. All of these come under the soil health principles.

We developed Sectormentor for Soils as a simple solution to help farmers monitor their soil health progression – seeing your soil health improve over time helps you to understand which farming methods are working for you, and hopefully give you an incentive to stay on a regenerative journey!

Learn more about making your soil rain-ready here, and learn about monitoring the impacts of water run-off here

Paper references:

  1. Congreves, K.A., Hayes, A., Verhallen, E.A., Van Erd, L.L. 2015. Long-term impact of tillage and crop rotation on soil health at four temperate agroecosystems. Soil and Tillage Research. 152: 17–28.
  2.  Parihar, C.M. Yadav, M.R., Jat, S.L., Singh, A.K., Kumar, B., Pradhan, S., Chakraborty, D., Jat, M.L., Jat, R.K., Saharawat, Y.S., Yadav, O.P. 2016. Long term effect of conservation agriculture in maize rotations on total organic carbon, physical and biological properties of a sandy loam soil in north-western Indo-Gangetic Plains. Soil and Tillage Research. 161: 116–128 
  3. Van Pelt, R.S., Hushmurodov, S.X., Baumhardt, R.L., Chappell, A., Nearing, M.A., Polyakov, V.O., Strack, J. 2017. The reduction of partitioned wind and water erosion by conservation agriculture. CATENA. 148: 160–167
  4. Baveye, P.C., Rangel, D., Jacobsen, A. R., Laba, M., Darnault, C., Otten, W., Radulowich, R., Camargo, F.A.O. 2011. From dust bowl to dust bowl: soils still a frontier of science. Soil Science Society of America Journal. 75: 6
  5. Barton, D.R., Farmer, M.E.D. 1997. The effects of conservation tillage practices on benthic invertebrate communities in headwater streams in southwestern Ontario, Canada. Environmental Pollution. 96: 207-215
  6.  Lal, R., Reicosky, D.C. & Hanson, J.D. 2007. Evolution of the plow over 10,000 years and the rationale for no-till farming. Soil and Tillage Research. 93:1–12

What is soil health and why should farmers and growers care about it?

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This is a guest post by Niels Corfield, soil health, agroforestry and whole farm planning advisor, researcher and advocate. You can find more articles from him on medium.

In this article I’d like to lay out the main tenets of soil health, but before that I want to present what I feel are the main motivations for “going to all that effort”!

Why bother about soil health?

First of all, in this climate change acceptance world, all forms of agriculture, and land use must wipe their face in terms of carbon. Being at least carbon neutral, if not carbon negative (or positive, whichever way you prefer it phrased).

All land, and all production must sequester carbon and it can, it’s been done, one example has raised their soil organic matter (SOM) from 2.4% to 8–11% in 6 years. 0.5–1% per year increases are regularly achieved.

Every single cropping cycle is a growth cycle and therefore should be net cumulative, in terms of carbon — through the process of root exudation. Simply put, all plants have the potential to improve soil (fertility), it’s the simply the management and composition of those plants (in space & in the rotation) that determine this fact. However, this is very hard to achieve when regularly cultivating, for example.

If you’re serious about climate change, business as usual is not an option. The good news is if you rigorously apply the same health principles production can be carbon negative.

What’s in it for us?

Apart from saving the planet, are there any other arguments for adopting novel practices? Is it just about doing good while our livelihoods suffer? Not at all!

Adopting the soil health principles wholeheartedly is one framework that can both address global issues and bring production benefits — showing that cropping (and farming) doesn’t have to be a zero sum game.

How would these benefits manifest? Everyone knows how well their crops look when the land is in good heart. And that that translates to fewer crop failures, less drought-stress, better infiltration and more yield. Moon on a stick? All of these are correlated with better soil health.

Another benefit of better crumb structure will equate to fewer passes to raise a seed bed, where cultivation is practised. That’s less diesel and better windows for field access (a window that’s fast becoming undependable). Either way there’s wins to be had once we harness the latent potential of plants.

Grass & fertility

Perhaps one of the few things that farmers (and growers) can agree on is that the land is “in best heart” the first year out of grass. So, is there something magic about grass, compared to other plants? Does it have unique “healing powers”?

Basically no, but to be clear, what is it we can say about the conditions under grass?

A living root, covered soil, undisturbed, diverse (ideally), some animal impact (potentially) and few if any chemicals.

Cropland (at left) — Grass margin (at right)

Soil fertility (health) can and should be built within the cropping phase of our operations, and can be achieved without going to grass. Not that grassing-down and fallowing aren’t efficacious practices, just that we have more tools available to us that are perhaps more appropriate in a cropping situation. We just need to closely mimic those conditions we find under grass, and that’s where the soil health principles come in — 7 ways to help you select management practices, and to make decisions on your operation that build soil: cropping or fallow, spring or fall.

One key insight — microbes matter

Perhaps the most important single insight that underpins, most, if not all of us or health principles is the understanding that microbes matter. And they matter to us the growers. But, why do they matter? What’s so good about them? And, what do they do for us? There are three parts to the answer:

Firstly they create crumb structure. Their actions bind together disparate soil particles into crumbs or “aggregates”.

Secondly, they feed plants. They digest elements out of the soil mineral matrix (as well as organic matter) and transform them into plant available nutrients. They literally eat rocks. Hitherto known as decomposition but since the process is done enzymatically it’s much more akin to digestion.

This is what’s known as the “microbial bridge”. Simply put, plants (and healthy plants in particular) are nourished by nutrients provided by organisms.

Thirdly microbes protect plants. Through a number of different mechanisms they either out compete or shield plants from disease-causing organisms and often pests as well. Perhaps the poster child of this final point is mycorrhizal fungi that snare root feeding nematodes which when caught are then digested and past up to the host plant.

So the plants are getting a pretty good deal here! They’re getting a nice loose structure to push their roots through easily, room service and their own live-in healthcare service. Are they getting all that for free? Emphatically no, this is where the soil health principles come in, read on..

The Soil Health Principles

Weed roots, rhizosheath forming (at upper left)

1 The Living Root — maintain a living roots in the soil for as long as possible and as often as possible

This is number one on the list because perhaps it is the most important. Because, simply put, roots make soil and they do this by producing root exudates, — carbon secretions that feed (and recruit) soil organisms, which in return deliver plant available compounds, right in the “root zone”.

Gothelney Farm: Rhizosheaths on oat cover crop (Photo: Fred Price)

If you want to see the effect of the living root on soil structure examine the soil around the roots of the healthiest plants on your farm (often a weed!). So the next time you’re out in the field, take a moment to carefully lift one or two plants and examine those roots. You will typically notice finally grained soil that has excellent crumb structure, potentially some of which may be actually stuck to the roots themselves, in what’s called a “rhizosheath”, this is a phenomenon seen where microbes are active and producing the glue like substances that bind together soil particles into aggregates. Where you see rhizosheaths you can infer from that that root exudation is taking place, as, without this carbon (energy) source these organisms would be inactive.

What you are seeing is soil building in action — where you are seeing crumb structure around roots and rhizosheaths. Without roots and root exudates, organisms become inactive, microbial populations become simplified and ultimately aggregates become consumed by those same organisms, since they have nothing else to eat, as these, glue-like substances, are all organic (carbon based) for example polysaccharides, hence are comestible. Literally the structure of aggregates is edible, Think Hansel and Gretel.

2 Covered Soil — protect soil, from wind, rain and sun, with leaves or residues

Maintaining a soil cover is essential. This is a fact that “nature intrinsically understands”, which is why bare soil is such a magnet for weeds, because without a cover, soil degrades quite rapidly, nutrients are lost, soil caps and water runs off. Ultimately that porous structure crumb structure that we all value is sacrificed. We should be taking steps to reduce the frequency of bare soil as well as the length of those periods.

Bare soil is the enemy of soil health. Don’t farm naked as some say.

3 Minimise Disturbance and Compaction — reduce tillage severity and frequency

No dig and no till are perhaps the foster children of the soil health movement but certainly it shouldn’t be reduced to this one single measure. Simply shifting to no-till and making no other changes will not bring the kind of results that we are really looking for. It will not bring health back to the soil on its own, it must be coupled with the other principles and particularly diversity. That said it’s worth expanding on the rationale for not tilling, by laying out the issues with tillage itself.

The first and most important point to make is that tillage destroys soil structure. This seems counter-intuitive because one of the primary reasons for tillage is to improve structure, or to get a tilth. While certainly there is a loosening effect post tillage, this is a short lived phenomenon, however, the structure of the soil is soon lost and it will then settle back into it’s more native, mineral-structured state, more akin to the subsoil. If all conditions are right then the crop can be established in this short phase, but this window is getting more unreliable by the day.

The reason that tillage destroys soil structure is because when we are talking about crumb structure we are talking about aggregates ultimately, and aggregates are made of small soil particles bound together with glue-like substances that have been secreted by organisms. When you till you break open these aggregates, splitting apart these crumbs, exposing them to oxygen at which point “R-strategist” organisms invade the space and rapidly decompose or digest (literally eat) the binding agents that glue together these crumbs. The process of aggregation is directly analogous to that of making biscuits in that the homogeneous flour (and sugar) particles are bound together by the butter or fat into larger non-uniform (heterogeneous) clumps or crumbs. In this analogy the sugar is analogous to sand and the flour is analogous to clay. And the fat is analogous to those binding agents, those polysaccharides that are biologically derived in the same way that a fat is.

Generally speaking if you want retain good crumb structure then reduce tillage — reduce the depth-, the frequency and minimise inversion.

That said, is there a place for tillage as a force for good? That depends much on the starting point. But there does seem to be a small number of clear cases where tillage (or mechanical interventions in general) can help to rectify the situations related to past management.

If your starting point is tired old pasture (But I thought you just said that pasture ticks all the soil health principles? Well yes it does, but management is always superior).See photo below: Old pasture (especially horse) may well be heavily consolidated and there’s only so much that your crop roots and even cover crop roots can do to undo this situation. In horticulture operation the Real Food Garden, they good results with ploughing the existing pasture and then a year of cover cropping before conversion to no dig.

Horse pasture (at right) — Fence line (at left)

4 Diversity — increase diversity in your plantings and rotations

Diversity above ground feeds diversity below ground. If you want your plant to have a balanced diet it needs to associate with a diversity of organisms that mineralize a diversity of nutrients.

It’s been shown that so that the formation of humic substances and stable aggregates is closely correlated with below ground diversity.

Below ground diversity requires a diversity of foods, from a diversity of root exudates etc.

This is one realm where cover crops can really excel. We can bring in so much diversity. And so long as we’re destroying without tilling, we can retain a significant portion of that beneficial structure. This diversity can be so much more, it can include C4 plants, which are rare and general in the UK cropping situations. Plants like maize, millet, sorghum, quinoa, amaranth, and the more common sunflower and buckwheat.

Trill Farm: High diversity (at left) — Low diversity (at right)

All these fancy seeds in a mix sounds expensive don’t they? Well it doesn’t have to be, just source your seeds from the feed merchant, rather than the seed merchant. Bird seed mixes are a great starting point and most of them already have the 8 species or more, recommended: broadleaves and grasses, warm season and cool season. And when the costs are low you can start sowing at proper seed rates which maybe 2 times or 3 times the standard advice. This overcomes the main pitfall people have when experimenting with cover crops: too little seed.

Schumacher College: Amaranth crop

That said, diversity isn’t limited to cover cropping. We can introduce diversity into our cash cropping operations. This is potentially where some of the biggest wins are actually to be had. Given that increasing species diversity from 1 to 2 represents a doubling in diversity that’s a big win. And going from 2 to 3 represents another 50% increase. So, include: catch crops, intercrops and relay crops whether practical.

There should be gains to be had in this case, so long as we doing our due diligence with the other soil health principles — especially around bare soil and the living root. Again we don’t want massive space between the plants being unfilled with roots and uncovered. This is where intercropping and catch cropping can really pay dividends.

5 Feed Soils — hungry organisms need food to stay active and healthy

This is definitely one area where the organic crew got it right. But what do we mean by this? What eats stuff in soil? Well organisms, life, life eats stuff. Not the “soil” per se, as this is simply a matrix of geological degradants.

What actually eats stuff in the soil is soil organisms: the soil food web members. So the question is then, what do these soil organisms like to eat? Really we’re talking about fungi and bacteria in this case, as they make up the vase majority of soil biomass. So, what’s their preferred food? Well in this case it’s root exudates. Simple to utilise (metabolise) foods such as carbohydrates, often as straightforward as glucose. But that is what’s being supplied by the roots, no? So, that’s covered under principal number one — the living root, right?

Well yes. Except we are in a cropping situation which means there may be a break in cropping. Where there’s a break in cropping, the organisms that are present in the soil, those active communities of bacteria for example that have built up, through your good management of cropping (and potentially diverse cropping) will all go dormant, but before they do, that they will consume the most readily available food source present. And what is that in this case? It will be the binding agents that hold the aggregates together. They will literally eat their own homes because there’s nothing else to eat. Evoking that famous phrase “burning the furniture” — when you’re snowed in and it’s freezing outside and you run out of firewood, you’re only alternative to keep warm is to burn the furniture but once you’ve done that where are you going to sit?

So what are we to conclude from this observation? Simply, where a break in cropping exists, provide a subsistence ration. This would typically be over winter. But either way, this is the prime time to apply bulky organic matter. And if all goes well, when you come to plant your next crop you will have a nice surface tilth and an active population of organisms ready to immediately associate with your plants.

The last two soil health principles are perhaps the least relevant to an organic growing situation. However I include them for the purposes of being thorough.

6 Incorporate Animals

Diversify your straight cropping operation by rotating animals or integrating livestock into your system.

So what’s good about animals? What benefits can they bring to a cropping system? Firstly, their manure contains inoculants that are rare, even in good compost and they can carry out the work of distributing (or applying) that manure through their own natural behaviour.

That said the key rationale behind this particular principle is that all ecosystems contain animals as part of the web, and they add a whole new dimension of diversity to the system so perhaps they should come under principal number 4, but in this case the desire is to be explicit.

Ian Boyd’s farm Whittington Lodge

7 Minimise Use of Chemicals

Simply put, the use of chemicals and synthetics undoes all of your good work further up the list.

Firstly, use of synthetic fertiliser or soluble nutrients in general discourage, the production of root exudates. Basically root exudation is a quid-pro-quo for plants. They’re effectively paying for nutrients in a form that they can absorb with energy (or sugars) the only currency plants hold. So, when a plant is artificially nourished through soluble fertiliser applications it’s need to offer exudates is removed, though this is fine in the short term, however, the removal of foods from our friendly minions (the soil microbes) means they will at best go dormant and at worst start chowing down on the aggregates themselves because there’s nothing else to eat and then go dormant.

Fertilisers in salt form, and in very high concentrations, actually force their way into the plant structure. So the plant almost becomes over nourished or certainly has no control over the quantities and types of nutrients that enter the cell structure.

Further to this and perhaps, more obviously is the use of pesticides etc which basically have all sorts of impacts on non-target species. But it goes without saying that applications of fungicides for example have detrimental effects on mycorrhizal fungi, though that said, so does tillage.

Putting it all together

Ultimately the strengths in this approach, this framework, is that the principles can be applied individually or in consort. But ultimately the real wins are to be had where all of the soil health principles are applied both in the cropping phase and fallow periods.

I like to think of the soil health principles as different levers maybe like you might picture in an old signal box, or a graphic equaliser. With each lever representing a different principle. Ultimately, over time want to be able to push all of the levers up to full, bring all of the benefits to bare.

Furthermore, for each principle there’s obviously a range. Similar to gears on a gearbox. Ultimately where limited by equipment or tools, it’s like being unable to change up from 3rd gear for instance. There’s nothing worse than being stuck in 3rd gear on the motorway. If we can gradually increase the upper maximum we can achieve each year we will gradually be able to leverage more of the latent power of nature to grow better crops.

Conclusion

So in conclusion, the soil health principles are another iteration of nature mimicry, offered, in this case to farmers and growers as a tool for decision-making on-farm.

Simply put, where two options are considered for a particular situation, that which scores highest, in terms of the soil health principles, should be preferred, where practical, or when it becomes practical.

I hope that you will use these principles in your day-to-day practice and in your longer-term rotation planning.

And for those that want to find out more, or discuss this in more detail please get in touch or consider joining me on one of my soils courses this autumn. If you have any thoughts or questions, get in touch: info@nielscorfield.com

Soil health courses & info
https://www.facebook.com/pg/nielscorfieldland/events/

Further Reading
Part 2 — Realising the Promise of Soil Health in Organic Horticulture
https://medium.com/@nielscorfield_90202/no-till-for-growers-realising-the-promise-of-soil-health-in-organic-horticulture-646fd553257

Soil Science Latest: How Can We Sequester More Carbon and Build Soil Health?

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A few weeks ago we presented at Wageningen Soils Conference with Elizabeth Stockdale, Head of Farming, NIAB. We shared about the work we had done together converting the AHDB soils scorecard into an interactive Soil Quality UK Dashboard, with the main focus being “How can we get farmers talking about their soil health, based on soil health tests?”. We had lots of brilliant feedback about the dashboard we built and everyone at the conference was very positive as we talked about the benefits of a very different, more thoughtful, type of user research.

Whilst we were there we also listened to many brilliant talks sharing the latest soil science, some of which were incredibly relevant to the farming community, so we want to share the insights with you.

Building short-term vs long-term Carbon – it’s all down to the microorganisms!

We have all heard of words like humus, humic acid etc in terms of soils and carbon stored in soils. Well it turns out in the words of Johannes Lehman, soil scientist at Cornell University “humus is dead”.

He was very clear that it’s false to think there is such a thing as a long term carbon store that is locked up forever.

The idea that stored organic carbon can be neatly separated into 3 different types (Rapid, labile, stable), which has been the model for many years, is not reflected in the research any longer.

We shouldn’t worry about the idea of building long term carbon vs short term carbon, essentially all carbon that is sucked into the soil via photosynthesis or decaying organisms has the potential to become long-term carbon. What actually matters is which microorganisms are present and what they do with it.

There is no clear silver-bullet pathway to locking up carbon for good, instead we can think of soil organic carbon as an ongoing cycle of carbon gains and losses which we need to constantly manage. To many farmers this may not come as a surprise – that is exactly what we have seen happening in the field. As we practice more regenerative approaches (living roots in the soil, ensuring plenty of plant residues etc) we are quickly seeing the advantages of healthier soils which is so often synonymous with higher soil organic carbon and a more alive soil system (i.e more microorganisms).

Read more in this paper: Microbial models with minimal mineral protection can explain long-term soil organic carbon persistence
Dominic Woolf & Johannes Lehmann  Scientific Reports volume 9, Article number: 6522 (2019)

Johannes showed that soil management techniques on farm to improve food security can have large beneficial effects on soil organic carbon. He drew from an example of changing agricultural practices in Ethiopia where they have been implementing agroforestry, diversified cropping systems, terracing, and many other agroecological practices — first and foremost as a measure to decrease poverty and prevent future drought scenarios. The project was undertaken on 600,000 Ha and had many benefits to the community, food security as well as environmental rehabilitation. However Johannes pointed out that it also had an unintended positive effect of sequestering significant amounts of carbon helping Ethiopia to meet their climate targets.

Read more in this paper: Land restoration in food security programmes: synergies with climate change mitigation
, & Climate Policy Journal Pages 1260-1270 | Received 24 May 2017, Accepted 05 Jan 2018, Published online: 26 Jan 2018

Carbon Current Account and Interest Rates

We discussed these findings with Elizabeth Stockdale, Head of Farming at NIAB, and she gave the analogy that this implies we need to think of our soils like a current account – you are constantly making deposits and withdrawals of carbon, and that will be reflected in your carbon balance. From a farming perspective, what I wanted to know is what is the interest rate on this current account? That essentially would reflect how effective we will be in the long run at sequestering carbon in soils and building up our SOC. The banking analogy also makes a lot of sense, as it reflects the fragility of soil carbon in the face of larger scale disasters and fluxes in the market, as everything can be ‘lost’ at any time.

In summary Johannes Lehmann’s work showed that the focus of building soil organic carbon should be on farm ‘short-term’ carbon cycling interventions (e.g cover cropping, leaving plant residues, agroforestry, composting applications, rotational grazing) and the microorganisms will do the work to build longer term carbon deposits from there! Unfortunately this new understanding of soil organic carbon and the value of microorganisms has not been incorporated into IPCC models yet, so the value of these practices aren’t fully taken into account in global carbon targets…but Johannes said it will all change quickly.

Johannes also posited that the traditional models for understanding soil, based on adsorption and aggregation, although helpful in their way, are not necessary to explain soil organic matter and soil functioning. His work has shown that soil organic carbon and soil function can all be explained by the makeup of microorganisms and the action of microorganisms in the soil. It’s early days for fully understanding this as we still only understand around 5% of all the microorganisms in our soils!

 

The Soil Microbial Carbon Pump – how do microorganisms affect carbon storage in soils?

One model put forward for understanding the effect of microorganisms in sequestering carbon in soils was the Microbial Carbon Pump, explained by Chao Liang from the Chinese Academy of Sciences. The Soil Microbial Carbon Pump is a model for understanding how microbes are an active player in soil carbon storage. Chao showed how it could be applied at many different scales from the rhizosphere (plant root-soil interactions) to the field and landscape scale, which could have implications for understanding the responses of ecosystem carbon processes to global environmental changes.

My interpretation of what he was saying is that there are two types of carbon sequestration pathways through soil microorganisms:

  1. Biomass: The living biomass of the soil i.e living microorganisms taking carbohydrates being offered by plant roots and using it for food, excreting it in the form of slimes, building fungal hyphae etc. This is what Dr Christine Jones refers to as the liquid carbon pathway. (Catabolic pathway)
  2. Necromass: All the dead material, whether plant residues or compost materials etc being broken down and processed by microorganisms. Increasingly scientists are recognising the important role this plays in building soil organic matter. (Anabolic pathway)

Read more in this paper: The Importance of Anabolism in Microbial Control over Carbon Storage
Chao Liang, Joshua P. Schimel, Julie D. Jastrow Nature Microbiology volume2, Article number: 17105 (2017)

Chao showed how this model allowed them to investigate the effects of plant covers on microbial communities and what that meant in terms of the magnitude and composition of the soil carbon pool. He outlined that once the Microbial Carbon Pump processes carbon, it will either be released back to the atmosphere as CO2 – known as the priming effect (i.e decreasing the storage life of the carbon) or further increase the storage life of the carbon – known as the entombing effect. Their results showed that as the fungal proportion in the microorganism community increases the amount of carbon that goes through the entombing effect and becomes longer term carbon significantly increases after a certain time and then remains constantly high, whilst the priming effect although initially peaks, it then decreases and falls significantly below the entombing effect (you can see this in the photos below, where the high fungal content soil sample is the middle graph, highlighted in red)

Essentially what that means is that in soils with a higher proportion of fungi, the carbon is more likely to be turned into longer-life carbon deposits.

What does this mean for farmers?

The scientists are saying that yes it’s all about building microbial communities if you want to increase soil organic carbon.

There is no silver bullet, but it will take new management strategies based on careful monitoring of carbon gains and losses and making sure you are building more carbon on a field than you are taking away.

We can very much see ourselves as key actors when it comes to reducing greenhouse gas emissions and sequestering carbon at a global scale and that employing methodologies that improve soil health and soil microbial communities are the best way to do this. Of course, we already know this is what regenerative agriculture, conservation agriculture, permaculture and so many other farmer-led practices are all about! But it’s good to know the scientists are behind it all, and we hope this will enter the minds of the policy makers sooner rather than later!

We learned a lot from the conference and you will see some changes to Sectormentor for Soils in the coming months as we reflect some of our learnings to bring you some new tools to help you understand what your soil monitoring results mean.

Use maps to save your sample locations

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We’re excited that you can now use the GPS mapping feature in both our iPhone and Android apps, to save the exact locations of where you are doing your soil tests in each field. That way you can very easily come back year after year to the same spot and monitor changes in soil health. We have spoken to many different soil scientists and advisors and we feel that the best way to monitor soil health on your farm is to select specific sample sites and observe trends/changes in soil over time at each site.

As all farmers know, there can be huge amounts of variability, even within a field, so the idea of finding an ‘average’ soil health for the field is difficult, and requires you to have many, many sample sites. So our advice is to just pick 1-3 sample sites in a field, and monitor how things change at each site as you change your management practices. To do this you need to go back to more or less the same spot, which is where being able to mark your sample sites on the map makes things easier!

What does this mean?

With our GPS feature, you can save the location of each of your sample sites within each field, so they appear as pins on the map. This means you can view the location of each sample on the map, and the next time you go out soil testing you have a precise point to go back to, to repeat the tests – just follow the map on your phone to find the same spot in the field.

Why does this matter?

Coming back to the same sample sites when monitoring information on your soils is important. It saves lots of time, as you can sample fewer locations in the field but still have a good idea of how your management is affecting soil health! That’s all because by going back to the same location, you reduce most of the variables, so you can be pretty certain that any changes in what you see and record are due to a change in management (or extreme weather conditions!). 

So, now you’ll really know if that cover crop helped improve your rooting depth and VESS score or not! With GPS you can locate your samples sites more accurately, you can view them on a map, and ensure you return to the same spot each time.

Got any questions about GPS and using Sectormentor for Soils to monitor soil health? Contact us!

Defragmenting UK soils policy – the journey so far…

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Much of what we do is about empowering farmers in the field to build soil health, but of course we realise that we are all part of a bigger system and government policy can have a massive impact on the way land is farmed.

We have always admired the work of the Sustainable Soils Alliance (SSA), bringing an independent and holistic voice to UK soils policy. Here Ursula Billington from the SSA gives us an update on the work they have been doing, what’s next for their policy work and how you can get involved if you are interested…

By Ursula Billington, Sustainable Soil Alliance, June 2019

At the parliamentary launch of the Sustainable Soils Alliance in 2017, the UK Department for Farming and Rural Affairs (DEFRA) Secretary of State Michael Gove charged us to hold the UK government to account on soil health and we’ve been doing this to the best of our abilities ever since. The principle aim of the SSA since inception has been to improve political and public understanding and appreciation of soil in the UK – and to identify the policy mechanisms needed to begin the reversal of land degradation and restore soil health within one generation.

We knew we’d have our work cut out and have spent the last two years ricocheting between positive, fruitful conversations with government, and leaps in appreciation of the frustrating complexity of the soils issue and policies it is embedded within. We’re delighted with the success we’ve had so far, but there’s still a long way to go to ensure the sustainability of our soils for generations to come.

The SSA was born from a knowledge of the crisis affecting soils across the UK, and the globe, and a sense that the time was right, with the dreaded Brexit allowing for a significant reshaping of policy, particularly around the agricultural sector. More recently the focus on climate and ecological breakdown has proved effective in inspiring a wider audience to adopt soils as a solution to the key challenges of our times, and to push even harder for farming, land and environment policy reform.

So the need was identified and the SSA formed a partnership of high profile government, environment, farming and NGO allies to give weight to the cause and generate urgent, immediate action. Two years later, we have established close working relationships with DEFRA, Department for Business, Energy and Industrial Strategy (BEIS), the Environment Agency and the emerging Environmental Land Management Schemes (ELMS) team. We have also inputted in to the new Agriculture and Environment Bills, the 25 Year Plan for the Environment, the new regulatory framework for farmers, the consultation on the future of Welsh farming and more. Success has been based on a slow but steady and reliable ongoing dialogue, a persistent chipping away at the rock-face of government, an endless search for the killer questions necessary to achieve our goals and, above all, – a non-partisan, relationship-based approach.

One of the first lessons we learnt – and a key one inspiring us to form a membership organisation representing all soil stakeholders across farming, land management, science, business and environment – was the siloed nature of thinking around soils. This may not come as a surprise and is certainly not unique to soils within government, but an issue we found to be both highly pertinent and damaging given the critical nature of soils to so many of our fundamental systems. Soil is the foundation of basic ecosystem function, intrinsic to food production, biodiversity and our natural environment, to water and air quality, to public health. It supplies medicines, stores carbon, prevents floods, helps regulate the earth’s temperature. It provides countless services which, if wearing a natural capital hat, have direct consequences for government spending and the Treasury. Its security is relevant to Defra, Natural England, the Environment Agency, BEIS, the Treasury, the Natural Capital Committee and more. Soil has been referred to by government as ‘the golden thread that runs through everything’ and features significantly in countless reports published by a multitude of agencies and departments. And yet the decision-making that encompasses it is fragmented. Building a joined-up strategy with soil health at its heart has therefore been a Herculean task, and we believe partnership working has been key to clarifying and supporting the flow of interdepartmental thinking. We’ve tackled this particular challenge by building ever stronger non-denominational relationships across the alliance, simultaneously working within departments to identify where their unique problems lie and help to deliver their own goals – whilst keeping in mind and working towards the wider context of interlocking aims and solutions.

As SSA Director Matt Orman recently put it:
“We have before us an opportunity almost unique to an industrialised nation to build from scratch a joined-up, fit-for-purpose national soil policy. This should reflect the scale of the problem and the political intent. We should seize it while harnessing the potential of technology and the groundswell of commitment in soil health among farmers, land managers and policy makers.

But what kind of policy is needed? All environmental governance depends upon the careful interweaving of key policy levers: regulations, education, incentivisation, monitoring and enforcement. The unique characteristics of soil such as its variety, ownership, timeframe and constituents represent a very particular challenge requiring careful consideration.”

The problem of fragmentation does not lie only within government. The SSA were not the first to identify or begin working to resolve the national soils crisis – there are a myriad of individuals, organisations and practical projects out there on a local and regional scale attempting to do just that. Breaking down silos, building relationships and attempting to unite with common leadership and purpose therefore quickly became a core approach of the SSA, in order to amplify the work of positive soils initiatives on the ground and present a united front to government. This partnership working also enabled us to fully understand the complexity of the challenge and the unique issues of the different stakeholders, as we engaged in conversations with as broad a representative of the soils community as possible. Critically listening, collating opinion and feeding back to government has become a key task of the SSA. We have convened meetings to include the widest possible spectrum of stakeholders, in part to help identify where conflicts lie and how to resolve these, building bridges and brokering to establish a level of basic agreement from which we can push forward to sustainable soils. We have not shied away from allowing like-minded and conflicting agendas to share the same space, and interesting outcomes have emerged as a result.

So where are we now? Under Gove, soil is at least now a part of government policy-making, which it hasn’t been before. There are encouraging references in the Agriculture and Environment Bills, and the 25 Year Environment Plan. But of course ministers are experts at saying the right thing, and we have yet to see concrete action on the issue. Soil has still not gained equivalent recognition and commitment as our other natural assets, water and air. We’re mindful of the need to pin down legislation, particularly at this time of tumultuous change and policy development within UK government. The temporary nature of ministerial positions and short lifespan of government can undermine progress and momentum at the best of times, so we’re working hard to firm up government commitments and ensure these are enshrined in new policy.

And we’re not afraid of change. Our fundamental aims remain the same, but within this framework we are constantly evolving, re-evaluating, responding to news, events, policies and ministerial attitudes, capitalising on new information and relationships that come our way. We aim to be agile, and we’re all too aware we may need to regroup around the change of leadership. These are interesting times, and there isn’t a blueprint for what we are attempting to achieve. But this makes it all the more important. We’re confident that strides can be made and we have hope for a step-change in soil health that will render our land, and all that stems from it, sustainable within one generation.

If you’d like to support our work please consider making a donation to help us grow.
For more on soils, Sustainable Soils Alliance projects and activities, visit our website.

Find more on our work with government here. Connect with us via twitter. If you’re interested in working with us please email ursula@sustainablesoils.org

Earthworm Engineers #4 – Manure & Earthworm Populations

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Welcome to the fourth and final post in our Earthworm Engineers series, where you can learn from some of the best science about the value of these amazing creatures. We’re so excited that Professor Jenni Dungait is now the editor of the European Journal of Soil Science – and she’s made some important earthworm papers open access for a month. We’ve picked our favourite four and summarised them in this blog series.

Access the earthworm archives in the European Journal of Soil Science, to learn more about the science behind on-farm worms!


#4: Quantifying dung carbon incorporation by earthworms in pasture soils

This study looks at the effect of different earthworm communities on the amount of soil carbon (within dung applications) shifted into the soil. They tracked this process by labelling the carbon with isotope tracing, which is a clever technique that gives a really specific picture of where exactly the carbon is moving to. The three main earthworm types were tested in different treatments: surface-dwelling worms (epigeic), deep-burrowing worms (anecic), and network-creating worms (endogeic).

First, the researchers found that with increasing inputs of dung, the abundance of earthworms tested also increased, presumably because the worms had a more consistent food source in these pots and could flourish!

Most of the tracked carbon was found in the soils top layer (0-75mm), although when the earthworm population included deep burrowing (anecic) earthworms, carbon from dung was often found at depths of up to 300mm, which shows just how effective these worms are at burrowing materials from the soil surface into its lower levels. The most successful treatments (with the greatest flow of dung shifted into soil organic carbon (SOC)) were those with all three types of earthworms present (epigeic, anecic and endogeic). So, a diverse population of worms is necessary for optimal dung break down into soils!

In pasture soils, dung left by livestock can therefore contribute to increased earthworm populations, as well as increasing soil organic carbon. This is important for the soils nutrient supply, and also helps to reduce CO2 levels in the atmosphere, which has potential to reduce the effects of climate change. In conventionally grazed systems, the quantity of dung deposited per hectare are less than the amounts used in this study, but it’s interesting to think about how this research adds to the evidence supporting mob-grazing systems, where livestock graze fields more intensively, and more manure is deposited per hectare as the stock moves through!


Earthworms are one of the best indicators of soil health – find out how to monitor earthworms on your farm.

Earthworm Engineers #3 – Organic vs Conventional Systems

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Welcome to the third instalment in our Earthworm Engineers series where you can learn from some of the best science about the value of these amazing creatures. We’re so excited that Professor Jenni Dungait is now the editor of the European Journal of Soil Science – and she’s made some important earthworm papers open access for a month. We’ve picked our favourite four and summarised them in this blog series.

Access the earthworm archives in the European Journal of Soil Science, to learn more about the science behind on-farm worms!


#3: The impact of soil carbon management on soil macropore structure: a comparison of two apple orchard systems in New Zealand

This study compares two sites of the same soil type under apple orchards on one farm. One site had been under organic treatment, with regular compost application and grass cover, while the other was under ‘conventional’ treatment, with regular irrigation, fertilisation and herbicide applications.

When testing for earthworm populations, the researchers consistently found more earthworms in the organic soil compared with the conventional soil. They also reconstructed the 3D ‘macroporosity’ structure of both soils using X-rays, and again found greater macroporosity within the organic soil compared to the conventional soil. This isn’t a coincidence! Macroporosity is defined as the network of pores with a diameter of over 0.3 mm in the soil, and earthworms are known to create these kinds of channels.

This increased macroporosity is important for several reasons. First, it is known to increase the rate that CO2 in the atmosphere is locked up as soil organic carbon (SOC), which both increases soil fertility and also has potential to reduce the rate of climate change. As expected, this study then found that the organic orchard had a 32% greater SOC content than the conventional soils! Increased macroporosity also improves the soil structure, as the stability of soil aggregates is increased, which allows more microbes to live in the soil.  

Denitrification rates are known to increase in anoxic, water-logged soils, which leads to increased emissions of N20, a gas that contributes to climate change. As a result, increased macroporosity reduces denitrification in the soil, by allowing oxygen to penetrate into the topsoil, and reducing the chances of water logging.

It’s amazing to see evidence of how organic techniques allow our earthworm friends to flourish, and how positive their presence is in orchard soils!

Read the fourth and final instalment of our Earthworm Engineers series here!


Earthworms are one of the best indicators of soil health – find out how to monitor earthworms on your farm.

Earthworm Engineers #2 – Arable Farming & Earthworm Populations

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Welcome to the second in our Earthworm Engineers series where you can learn from some of the best science about the value of these amazing creatures. We’re so excited that Professor Jenni Dungait is now the editor of the European Journal of Soil Science – and she’s made some important earthworm papers open access for a short time. We’ve picked our favourite four and summarised them in this blog series.

Access the earthworm archives in the European Journal of Soil Science, to learn more about the science behind on-farm worms!


#2: Effects of different methods of cultivation and direct drilling, and disposal of straw residues, on populations of earthworms

This paper was written in 1979, and uses some pretty intense soil sampling methods (dousing the sample sites with formaldehyde to isolate worms) – we think they probably could have done with Sectormentor for Soils to count earthworm populations at each site!

The paper makes some interesting conclusions about the effects of cultivation on earthworms in topsoil. They tested the number of earthworms over four years on direct-drilled fields that were sprayed with herbicide before planting, and ploughed fields (of varying soil types). They found earthworm populations were consistently greater in the direct-drilled soils compared with ploughed soils, although deep-burrowing species were affected similarly in both treatments.

They also test the effect of spreading mulch on the fields compared to burning straw residue, and find (unsurprisingly) that earthworm populations were greater in fields where straw residue was spread rather than burned, particularly in surface feeding species. This surface debris becomes an important food source for the worms, and makes their diet more stable.

The paper also suggests that the extra earthworm channels created under no-till soils may help to reduce any compaction in the soil, as well as distributing organic matter and increasing drainage. The presence of worm channels may also allow plant roots to penetrate more deeply, which can also reduce compaction.

It’s nice to know that regenerative farming approaches have such a positive influence on the earthworm community. We’re really excited to speak at Groundswell this year on how to become a soil expert on your farm, and to learn more about the benefits of no-till systems.

Ready for to learn even more about the wonder of worms? Read part 3 of Earthworm Engineers here.


Earthworms are one of the best indicators of soil health – find out how to monitor earthworms on your farm.