improving soil organic matter · improving soil organic matter “if you can have your soil in...

All it took were a few poor vegetable harvests to

convince Mike Werbicky to try something new on the

55-acre family farm he took over from his father in

1985. The soil was in rough shape, sporting gullies and

areas of ponding after rainstorms. Even after irrigating,

the water just didn’t seem to infiltrate well. These

issues persisted despite a change to a wheat/soy

rotation. More change was needed for this St. George

area farm.

Patience pays off Huge improvements in the soil were noticed after Mike

moved to a no-till system a few years ago, especially

once cover crops, such as sorghum, clover, radish and

cereal rye, were integrated into the rotation. Now when

Mike checks his field after a storm, even if the field

was already moist before the rain, it can still absorb

more water. This small change has led to others: the

organic matter levels have risen from 1.6%to 2.1%,

ponding has stopped and soil erosion is no longer an

issue. As Mike proudly explains, “It’s payback time.”

Mike looks forward to many more years of soil

improvement with cover crops in his rotation.

And an added bonus of no-till, according to Mike,

“I save on fuel!”

“Cover crops don’t have to be complicated.”

-Ted Stroh, Wellesley farmer

M i ke We r b i c k y

Stories from the Field:

Improving Soil Organic Matter

“If you can have your soil in better shape

to absorb the water, it’s a win-win.”

Soil that is high in organic matter is darker as seen in the top layer of this soil profile.

FOR MORE INFORMATION

Part of the Great Lakes Agricultural Stewardship Initiative 519-621-2761 or ruralwater@grandriver.ca

What is soil organic matter? Organic matter consists of plant residues, humus, plant

roots, invertebrates and microorganisms such as fungi

and bacteria.

Why is soil organic matter important? Healthy productive soils need organic matter for:

Soil Nutrients– Organic matter adds crop nutrients

and feeds the microbes needed for nutrient cycling

and storage.

Water holding capacity- Organic matter acts like a

sponge in the soil. It easily absorbs water, making

soils more resistant to drought.

Soil structure aggregation– Organic matter

supports the biological processes that bind soil

particles together into small clumps or aggregates.

The spaces in and between soil aggregates allow

for water and air exchange and promote plant root

growth.

Erosion prevention– Soils with higher organic

matter have greater aggregate stability, making

them more resistant to the erosive forces of wind

and water.

How to build soil organic matter Add organic amendments like manure or compost

Reduce tillage. This slows the breakdown of

residue and minimizes disturbance to soil

microbes.

Diversify your crop rotation or plant cover crops to

increase residue and keep living roots in the soil

longer.

Photo courtesy of USDA NRCS

What should my soil organic matter level be?

This varies by soil type, usually anywhere between 1% and 5%. Higher percentages are needed for good aggregate stability.

Check the table below to see how your fields compare:

Source: http://www.omafra.gov.on.ca/english/crops/pub811/8building.htm

Organic Matter Targets (%)

Soil Texture Productivity Aggregate Stability

Sands and sandy loam

4 3

Loam and silt loam

4-5 4

Clay loam 4-5 7

Clay 4-6 9