No-till agriculture involves understanding soil biology, how to improve it: expert

CHATHAM-KENT, Ont. — Odette Ménard’s interest in no-till began with equipment, but the soil specialist with Quebec’s agriculture ministry now relegates hardware to a supporting role.

“No-till is not the solution in itself,” she said at Tomato Day March 3. “We have to get into the whole system.”

Ménard said transitioning to no-till or zero-till is a bit like running a marathon. The ability to finish the distance requires a full commitment to a training regimen.

Farmers must focus on crop rotation, residue management and cover crops and understand their soil resource from the perspectives of biology and physical dynamics.

It’s in these last two areas that farmers might begin.

Ménard advises farmers to dig a couple holes in their fields, about 75 centimetres across and 75 cm deep, choosing high and low producing areas.

Hopefully they will find sweet-scented, crumbly, well-textured soil and the absence of compacted zones. If not, at least they will have gained an understanding of the current situation.

Soil tests can also be useful, but farmers should look beyond nutrient availability to organic matter, which is one measure of soil biology.

Another is the presence of earthworms. Ménard said farmers may be able to count 12 middens for every 10 sq. feet of healthy soil when worm activity peaks. That’s about 500,000 to 600,000 middens per acre.

The middens represent just one earthworm species. There can be 25 earthworms per sq. foot of soil, and earthworms represent just 20 percent of the living biological mass of the soil.

“In one handful of soil, you can have up to 10 feet of fungal mycelium and up to a billion bacteria,” she said.

“About 95 to 98 percent of the organisms in the soil are good guys. Only two to five percent are bad, but they can be pretty tough. That’s when we’ve killed off too many of the good guys.”

Tillage is tough on soil life, as is the absence of residue and living plants, whether it be crops, cover crops or both.

“Brown is bad, gold is better and green is great,” she said.

Ménard sees no-till and cover crops as the means to move forward in an agriculture era dominated by continuous cropping systems.

She said the plow made sense in certain respects a century ago when there were mixed farms and horsepower. Farmers did not turn all their land over each year. Some fields were in pasture or forage and others were left fallow to rest so that they could biologically regenerate their fertility.

The plow, when applied to sod or fallowed land, release that stored fertility, controlled weeds and temporarily improved drainage.

Cultivation continued to be used with the advent of chemical fertilizers, but there were also drawbacks, Ménard said.

Erosion became a concern, biology an afterthought and the farm community forgot why it had used cultivation in the first place.

Today’s continuous cropping systems, crop rotation and cover crops better harness solar energy by tapping into the biological potential of the soil on an almost year-round basis.

Soil structure is improved and along with it water infiltration and water-holding capacity.

Soil bacteria stop working only at 10 C and fungi at 0 C.

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