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Carbon key to building resilience on farms

Building soil carbon supports soil biota and makes for a healthier farming system

Farmers often see themselves as feeding the world, but farmers attending the Organic Connections conference here recently were told the first step towards that goal is feeding the “starving and homeless” micro-organisms in their soil.

Kristine Nichols

Kristine Nichols
photo: Laura Rance

“Your job is to feed them and maintain their habitat,” Kristine Nichols, the chief scientist with the Rodale Institute told farmers attending the Organic Connections conference Nov. 3 in Regina.

“There are 10 billion organisms and all they need from you is food and a place to live.”

The Rodale Institute, based in Pennsylvania, has been researching organic farming systems since 1947. Much of its recent work has focused on reducing or eliminating tillage in organic systems.

Nichols said finding ways to add carbon is key to building resiliency into farming systems. “Soil is your most important resource, if you don’t feed it, it’s not going to feed you.”

She said evidence is showing the cost of farming rises as soil quality declines. “What’s happening is the amount of nitrogen that is needed is actually going up. It takes more nitrogen today to grow a bushel of grain than it did in 1960,” she said. “The reason is, we have decoupled the system from biology.”

Nichols, a soil microbiologist, said adding cover and green manure crops and reducing tillage can help restore the diversity of organisms within the soil, which in turn improves its ability to nourish crops and efficiently use water.

She is suggesting farmers shift their focus from using high yields to measure the success of their farming system to focusing on high carbon.

The balance between carbon and available nitrogen can be improved by using different combinations of crops, rotations and including perennial legumes in the mix.

But there are no shortcuts or “bug in a jug” farmers can buy to accomplish that goal, she warned. “If you can afford to go out and do that, then you can afford to change your system. There is no immediate gratification.”

Nichols said the biological webs beneath the surface are “incredibly elegant” and easily destroyed by tillage operations. If farmers do till, they need to provide an environment that allows those networks to reform as quickly as possible.

Nichols told farmers it’s impossible for her to advise them on which cover crop mixes are best because soils in different areas and in different phases respond differently. There is no one single recipe that will work for all, rather principles that can help guide their decisions. “It takes time, patience and thought.”

Two of those principles include including perennials and livestock. “Overall, as far as helping build biologically healthy soil, having a perennial phase in the system is really important,” she said.

Livestock is also an asset when attempting to build an integrated approach to improving soil biology because it is adept at recycling nutrients.

The three-day conference attracted about 150 farmers.

This article was originally published on OrganicBiz.ca.


Soil carbon offers unsung benefits

Soil carbon, in the form of soil organic matter, has a number of widely recognized benefits for crop production.

  • It is a slow-release form of key nutrients including nitrogen, phosphorus and sulphur that helps both plants and soil microbes to thrive.
  • It can hold more water and release it as needed, helping protect crops from dry conditions.

Organic matter helps stabilize the pH and acidity of soils.

  • Carbon-rich soil is darker than soils without it, so it warms more quickly in the spring.
  • Organic matter binds soil particles together, much like glue, and makes soil less prone to erosion.
  • It binds nutrient ions, such as potassium, calcium and magnesium, in the soil to prevent losses through leaching.
  • Some of the organic material in soil humus is thought to act as plant growth stimulants.
  • Soil organic matter is a major part of the Earth’s carbon cycle, and is thought to be twice as large as the plant and atmospheric pools.
  • Organic matter also plays a major role in the ability of soils to tie up or absorb pollutants, where they can then be degraded by soil organisms.

Source: prairiesoilsandcrops.ca

About the author

Editorial Director

Laura Rance is vice-president of content for Glacier FarmMedia. She can be reached at [email protected]

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