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CMP October Update – The Principles of Regenerative Agriculture – Nick Wall


The Principles of Regenerative Agriculture

The soil beneath our feet is arguably our greatest asset. It’s certainly one that deserves our greatest respect, but it sometimes doesn’t get to be treated quite as well as it should. Sometimes we abuse its largely forgiving nature: The ever more frequent weather extremes over the summer and autumn often lead to sub optimal crop establishment.

Coupled with this, ever increasing input costs more than ever, make me wonder if we should, or even could, stay on this hamster wheel. Wouldn’t it be great to be able to maintain or increase yields, reduce our costs of production and maybe even improve our work / life balance in the process!

Regenerative Agriculture practice offers a solution to these issues, and it is really very easy for anyone to adopt.

Perhaps the first step is to think of our soil as a living, breathing biological system, rather than just dirt. This is referred to as the Soil Food Web. We might understand the chemistry, physics and classification of our soil, but do we know how it functions? What conditions do we need to have in place for the soil to be able to operate at its biological optimum? What practices can we adopt to help our soil function at its best?

I challenge you to go and compare the soil in one field with that close to a hedge in the same field – soil that has been conventionally tilled with one that has not. It’s the same soil type and texture, but they are probably quite different in structure, colour and smell. The soil under the hedge will be operating near its optimum. Here the soil food web should be self-sustaining.  Listed below are a few principals you can adopt to help the soils in your fields- the ones you rely upon for your living – to be more like the soil from the pit near the hedge.

Less soil disturbance

Each time we till the soil, we break up the soil aggregates. The act of tillage disrupts the complex network of earthworm burrows, fungal hyphae and labyrinth of microscopic air pockets that all give the soil its integrity. This disruption can then lead to compaction, capping and slumping. Nutrients may be mobilised and washed out of the soil profile. Tillage exposes dormant weed seeds to light, triggering germination. They might be best left on the surface where they can rot or be eaten by rodents or insects. Tillage activates soil microbes which feed on stored carbon, reducing soil organic matter and water holding capacity of your soil. Summer droughts and winter waterlogging become more prevalent.

Once we remove tillage, the soil can restructure itself biologically, but it needs our help, it needs living plants, in fact, it needs the whole Soil Food Web to build and restore its integrity. We can help to speed this process up by adopting the techniques outlined below.

More Plant Diversity

We know ourselves: ‘Man shall not live by bread alone’. Like humans, the soil is a living biological system with a biome. It needs a varied diet, plants or moreover, their root exudates provide food for the soil. The wider variety of plants in the cropping system provided by wider, more varied crop rotation and from more diverse cover cropping, or even companion cropping where we might bicrop different species such as Oat and peas, or companion Oilseed rape with vetch, buckwheat and clover. Greater diversity of food leads to a healthier Soil Food Web.

Greater diversity also enables a wider range of insects to grow within the field. This is very important as it often means one single species is prevented from dominating – there are many predators. When we plant a field of wheat or Oilseed rape, we allow the animals who specialise on feeding on that plant to dominate, we are inadvertently providing ideal food for slugs, aphids and flea beetles and we wonder why they prosper!

Keep the soil surface covered

Our soil needs to be physically protected from temperature change, the impact of raindrops, and subsequent surface flow after a heavy rain shower. A layer of straw residue offers insulation and protection. It’s often referred to as ‘soil armour’ Cover crops and even the cash crop offers decent protection to the soil surface. We have all seen how quickly soils dry once the crop has been harvested. This was very clear to see in Oilseed rape crops planted after spring barley chopped straw. There was plenty of moisture right through the August drought and the crops have consequently flourished. The type of cover crop we select will have a great influence on future residues and soil protection: mature brassicas and cereals will leave woody stems with a high carbon: nitrogen ratio that provide longer lasting cover. Residues also prevent weeds from germinating and provide a habitat for natural pest predators.


Maintain living roots

Plants have a key role in soil functioning, since they provide the energy which fuels the biological engine. This energy is derived from sunlight, photosynthesised into sugars for use by the plant, but they are also exuded through the roots to feed the soil organisms. As long as a soil has plants actively growing in it, carbon and associated energy will be delivered below ground, with all the associated benefits. In the absence of plants, the soil biota continues to metabolise soil organic matter and releases carbon (as carbon dioxide, CO2) via respiration, which passes to the atmosphere. Mycorrhizae are particular types of fungi which connect to plant roots and effectively extend the volume of soil which is explored by the plant. Mycorrhizae acquire nutrients – especially phosphorus – and pass them to the plant at rates far more rapidly than can occur via diffusion through the soil. Mycorrhizal hyphal networks play a part in maintaining soil structure via binding and coating mechanisms. We can play our part to encourage and promote mycorrhiza by ensuring the presence of host plants in the soil, maintain living roots and minimise disruption of their delicate hyphal networks via tillage. An interim cash or cover crop will keep the soil cycling between the main crop plantings, helping to retain available nutrients, enabling us to reduce crop fertiliser applications.

Livestock or organic manure integration

Clearly, we don’t all have a mixed farm, or have access to a local source of FYM but we may be able to bring in sheep to graze covers or turnips before spring crops. The main aim is to try and improve the organic matter content of our soils, this can be done by a number of means: Grazing sheep on turnips and cover crops is ideal, importing FYM, poultry manure, horse shavings, digested biosolids and compost. Even chopping straw, or establishing a muck for straw deal with a neighbour, will have a beneficial effect on your soil health.

We are all, in fact livestock farmers. We have great influence over the productivity of the many organisms that live in our soils from Bacteria, Actinomycetes, Fungi, Basidiomycetes, Protozoa, Nematodes, Enchytraeids, Arthropods Earthworms and Mammals. Soil that provides a beneficial habitat for all the members of the soil food web will allow them to build soil aggregates and restore the capacity of the soil to function. This capacity of the soil to infiltrate water and cycle nutrients is critical to the profitable production of our crops.