Regenerative agriculture helps improve soil health

‘Regenerative Agriculture’ is a new term that is starting to develop on some farms where producers are looking to improve the soil health on their operation. One component of soil health that has perhaps been neglected in the past is our understanding of how plants and soil microbes contribute to healthy soil.

Australian soil scientist Dr. Christine Jones challenges the conventional model of agriculture which has told us that ‘plants take from the soil’. According to her, nothing could be further from the truth. She states: “Observe what happens in bare soil. It dies, then it blows or washes away. If you could see what happens around the roots of actively growing plants you would want to have as many green plants in your soil for as much of the year as possible. It is not ‘natural’ for the soil to be bare over summer.”

Science has shown us that on a given piece of property, over 95 per cent of terrestrial diversity is within the soil itself ( less than five per cent is above the ground). Jones says that in order for this soil life to f lourish, the soil ecosystem requires fuel in the form of carbon ( from green plants) and ‘ habitat’ in the form of high root biomass. She further suggests that the soil surface requires year-round protection from erosion and temperature extremes ( both highs and lows). According to Jones, it is ‘ life’ that gives soil its structure, enabling the infiltration and retention of moisture, restoring water balance across the landscape and reversing the processes of desertification, and it is ‘ life’ that provides natural fertility, sequestering carbon, nitrogen and sulfur from the atmosphere and increasing the availability of phosphorus and trace elements in the root zone. According to Christine Jones, the fundamental question in regenerative agriculture is: “how do we get life back into the soil?”

There is increasing recognition of the fundamental importance of soil microbial communities to plant productivity. According to Jones, many biological functions are compromised by commonly used agricultural practices. She outlines four basic principles of regenerative agriculture, proven to restore soil health and increase soil carbon and nitrogen.

1. The first principle is the maintenance of yearround living cover, via perennial pastures on grazed land and/or multispecies cover crop on farmed land. Almost every living thing in and on the soil depends on green plants (or what was once a green plant) for its existence. The more green plants, the more life.

It’s well accepted that groundcover buffers soil temperatures and reduces erosion, but it is perhaps less recognized that actively growing green groundcover also fuels the liquid carbon pathway which in turn supports, among other things, mycorrhizal fungi, associative nitrogen-fixing bacteria and phosphorus solubilising bacteria – all of which are essential to both crop nutrition and the formation of stable humified carbon.

2. The second principle is to provide support for the microbial bridge, to enhance the flow of carbon from plants to soil. This requires reducing inputs of high analysis nitrogen and phosphorus fertilizers that inhibit the complex biochemical signalling between plant roots and microbes.

3. The third principle is to promote plant and microbial diversity, the greater the diversity of plants the more checks and balances for pests and diseases and the broader the range of microhabitats for the soil organisms involved in nutrient acquisition, nutrient cycling and soil building.

4. The fourth principle is that land responds positively to the presence of animals provided management is appropriate. Rota- tional grazing of livestock on perennial pastures is the fastest and most economical way to improve soils. As well as the benefits arising from the addition of manure and urine to soils, high intensity short duration grazing increases root exudation and stimulates the number and activity of associative nitrogen-fixing bacteria in the root zone, which fire up in response to defoliation and provide the extra nitrogen required by the plant for the production of new growth.

For more information on this topic, you can contact Trevor Lennox, Regional Forage Specialist in Swift Current at 306778-8294, or trevor.lennoxgov.sk.ca , or you can view a collection of papers by Christine Jones at the following website: www.amazingcarbon.com.