Regenerative Agriculture: No-Till farming for soil health and carbon sequestration

Farmlands have traditionally been ploughed in preparation for planting to: control weeds, remove plant residue, and loosen compacted surface soil.This traditional method involves turning over the first six to ten inches of soil prior to planting, pushing the surface crop residues, animal manure, and weeds deep below the surface, and aerating and warming the soil. 

In addition to its functional efficacy, conventional tillage provides a temporary source of nutrients for the crops; these functions and benefits are outweighed by negative consequences in the soil health and carbon sequestration arenas:

• Tillage leaves the soil surface bare, rendering it susceptible to erosion by wind and water
• Soil particles are loosened, a further erosion risk
• Tilling displaces and/or kills the microbes and insects that contribute to a healthy soil biology
• Can increase the dependence on chemical inputs for productivity
• Carbon, in the form of organic material such as plant roots and micro-organisms, are brought to the surface, where exposure to the atmosphere turns the carbon into CO₂, contributing to greenhouse gas emissions.

Conservation tillage and no-till, detailed in the chart below, have been advanced as approaches which robustly address the shortcomings associated with conventional tillage.

No-till is the recommendation in the Regenerative Organic certification, a designation recently attained by Applegate Valley's Troon Vineyard. According to Craig Camp, General Manager, Troon Vineyard is moving to no-till as quickly as they can. In Craig's view, "the foundation of practicing biodynamics is the regeneration of the natural microbiome of your soils. No-till is the natural partner to biodynamic farming as few things are more disruptive to the mycorrhizal community in your soil than tillage. On top of that is carbon sequestration that no-till farms support. This alone is reason enough to transition your farm to no-till."

Dyer Wines and Youngberg Hill are also using no-till. Dyer Wine, in its use of no-till, has found:

• Carbon is sequestered in the soil
• Soil texture improves
• Fertility and nutrient uptake are enhanced
• Increased worm populations drag organic matter down into the soil
• Vine roots go deeper
• Water retention increases several fold.

Youngberg Hill from Willamette Valley initially plowed under the cover crops to limit/eliminate water competition for the vines. Over the years, however, they have discovered a number of advantages associated with cover-crop retention. Further, they have come to understand that the "microbiological environment that lies below the soil is key to improving and sustaining healthy soils" and for that environment to remain healthy, it must remain undisturbed.

Within the no-till category, there is a further delineation of organic versus conventional. In the case of conventional no-till, a farmer can use chemical herbicides to kill cover crops before the next planting. In some cases the herbicide used is greater than the amount used in tillage-based farming. No synthetic inputs are allowed in organic no-till. Rather, the farmer uses cover crops, crop rotation, free-range livestock and available tools. Small-scale organic farmers use hand tools, such as hoes and rakes, while large-scale farmers can utilize tractor-borne implements.

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