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Farmers have to rely on biology

By Carol Stender
cstender@agrinews.com

Date Modified: 08/30/2013 12:59 PM

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MORRIS, Minn. —Grass is what "drives the bus" in the pasture-based organic dairy system that Cindy Daley manages.

Daley, a California State University-Chico dairy researcher, told the more than 80 people at the West Central Research and Outreach Center Dairy Day last week that amending soils is important to create healthy pastures.

When she came to the university as a graduate student, CSU had a conventional dairy that was part of the university's 800-acre farm.

School officials didn't want to lose money on the operation. She looked at other systems that would be sustainable. Researchers turned to a pasture-based system and found that organic programs seemed to have the most going on.

The school's conventional herd was sold, and crossbred Jerseys were acquired.

"The Jerseys have the best net profit," she said. "I don't want to be on the cover of Hoard's Dairy. We don't have net production, but the Jerseys do a good job utilizing the pasture."

The soils the dairy got to work with in their pasture-based systems weren't the best, she said. Researchers looked at ways to build the soil up for forage production.

The grasses are her cheapest feed.

While developing the pastures, she's building the soils.

"That's your bank account right there," she said. "That's your legacy. How much soil are you banking? That's your resiliency right there."

It starts with the soil's "floor space." The soil biology will have fungi, earthworms and bacteria. The biology is doing the work for you, she said. Nutrient cycling and nutrient retention are going on. The process improves soil structure, infiltration and water holding capacity.

The more "good bugs" there are in the soil, the more those bugs will move out the bad ones, she said.

Chemical attributes in the soil's make up will have an impact on productivity, she said. Calcium, magnesium, potassium, sodium, hydrogen, phosphorus, sulfur and chlorine are among the important chemicals. The main elements, iron, maganese, zinc, copper and boron, have many interactions within the soil.

The cation exchange capacity is the measure of soil's ability to hold and release nutrients. Higher CEC soils have more clay and organic matter.

High-quality forage should have a crude protein of 18 percent to 21 percent, an ADF of 28 percent to 30 percent, an NDF of 40 percent to 45 percent with energy around 0.65 to 0.70 and calcium greater than 1 percent to 1.5 percent.

An initial soil test revealed that it was "tight" with low nitrogen, low calcium, sulfur, boron and zinc with an excess in magnesium. They started to turn around the soil profile over the next seven years.

Researchers added more calcium. It's the facilitator for moving nutrients into the plant, she said. Calcium deficiencies affect plant growth.

A lack of boron may create issues where sugar can't go into the plant. Sulfur is important for protein production and the digestibility of lignin, she said.

They studied the affects of adding the nutrients to pastures. The farm's 50 acres of pasture was broken into five-acre blocks with managed intensive grazing. The cows, on 12 hour rotations, were fed after every milking. The five acre blocks had randomized treatment that were either amended or non-amended.

The paddocks received 21 days of rest in spring and 35 days of rest in summer.

Rye, brome, prairie grass, clovers, brassicas and forbs were planted in the pastures, she said.

In the heat of the day, the cows are fed a cover crop type silage.

The added soil nutrients caused grasses to thrive with more dry matter.

While the pastures produced more grass, the cows also produced more milk, she said.

The paddock produced around 5 tons of dry matter per grazing system. That was 1,658 pounds more milk per acre which equaled to $497.55 per acre.

"If you are an organic farmer, you have to rely on the biology," she said. "The moral is balanced soils do make better forages, which also makes more milk, happy cows and more sustainable farms."