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Organic transition: Knowing your way around nutrients

The right crop selection and nutrients can go a long way in easing the transition from conventional to organic production.
Carol Ryan Dumas

Capital Press

Published on December 7, 2015 5:17PM

Carol Ryan Dumas/Capital Press
Amber Moore, University of Idaho soil fertility specialist, talks with Grant Laudert, district sales manager with KeyAg Distributors, during a break at the Organic 101 workshop sponsored by the Northwest Center for Alternatives to Pesticides. The workshop was in Twin Falls, Idaho, on Dec. 3.

Carol Ryan Dumas/Capital Press Amber Moore, University of Idaho soil fertility specialist, talks with Grant Laudert, district sales manager with KeyAg Distributors, during a break at the Organic 101 workshop sponsored by the Northwest Center for Alternatives to Pesticides. The workshop was in Twin Falls, Idaho, on Dec. 3.

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TWIN FALLS, Idaho — Yield losses are often associated with transitions to organic production, but that does not necessarily have to be the case, an organic expert says.

“It’s not as scary as you think it is,” University of Idaho Soil Specialist Amber Moore told the Organics 101 workshop, hosted by the Northwest Center for Alternatives to Pesticides on Dec. 3.

“There are tips and tricks to manage nutrients and get through the transition period. If you build the soil, the yields will eventually come,” she said.

Conventional farming maintains nutrients in the soil through widely available commercial fertilizers, and established organic operations build nutrients. But transitional production mines nutrients from the soil, whose nutrient reserves are limited from the lack of organic practices, she said.

While nutrient-rich fertilizer sources are limited in organic production, they are available, and the crops grown during transition are just as important as nutrient management, she said.

“This is not the time to be growing potatoes,” she said.

Transitional growers, who won’t be able to command premiums from organic production for three years, should select crops with minimal nutrient needs and overall low maintenance that have aggressive growth against weed pressure, she said.

At the top of her list is alfalfa. Yields are often comparable to conventional production, it makes its own nitrogen and is aggressive against weed pressure. In addition, alfalfa is a perennial that can be left for the three-year transition period, and it has good soil-building properties.

But alfalfa does not make its own phosphorous and potassium and instead draws them from the ground. If those nutrient levels in the soil are low to moderate, producers should consider incorporating cattle compost prior to planting at a rate of 10 to 15 tons per acre. The compost will release nutrients over time and is a rich source of organic matter to build the soil, she said.

Other good crop options are pasture grass and hay (perhaps in a blend with alfalfa to meet nitrogen needs) and small grains, which better accommodate annual incorporation of compost, she said.

Moore highly recommends avoiding row crops if possible during the three-year transition period.

“Make your life easier. Save yourself a little bit of grief,” she said.

Transitioning farmers who plant row crops often don’t make it to the organic certification stage, she said.

If growers must plant row crops, they should rely heavily on nutrient-rich organic sources and select varieties with lower nutrient requirements and “not just during transition because nitrogen is always something you’ll probably be chasing,” she said.

Transition is a good time for applying and incorporating slow-release organic nutrient sources that contain significant amounts of stable organic nitrogen compounds and reduce nutrient deficit issues for future nutrient-hungry row crops, she said.

Common options for Idaho are cattle compost and cattle manure, she said.


Post-transition


The good news about the period following transition is “you made it through,” Moore said, adding, “but you’re still not in the clear.”

Getting stable nitrogen reserves built up in the soil takes time. Combining routine compost applications with “quick fix” nutrient applications can get growers through the nutrient-deficit hump while building long-term nutrient reserves, she said.

Those quick fixes need to be rich in nitrogen, 3 percent or greater. Nitrogen rarely carries over into the next season, and the fixes can be expensive and aren’t always sustainable. But they can save growers from significant yield losses while building soil nutrients, she said.

Such fixes include sodium nitrate (or Chilean nitrate). Its use is restricted to no more than 20 percent of the crop’s total nitrogen requirement. It’s good for getting over the hump, but growers need to monitor for sodium toxicity, and some overseas markets don’t consider it organic, she said.

Oilseed meals — such as mustard, canola and soybean meal — are another good option. They are rich in nitrogen and offer good nitrogen availability, but competition from livestock feed markets makes them expensive.

Many other sources such as blood, bone, fish and shrimp meals are also available, she said.

Whatever nutrient source they choose, growers should be sure it is, or still is, approved for organic production, she said.

“Things are constantly changing. Always, always, always work with your certifier,” Moore said.

Once established, after about five years or so, organic operations will have a higher population of beneficial biological organisms, better pest suppression, improved soils and adequate nutrient reserves.

But growers will need to keep up the good work. Moore recommends they keep up with additions of compost, plant residue and other stable organic sources and keep soil-building crops such as alfalfa in the rotation.

They should also continue soil-testing efforts to prevent nutrient overload or underload, be open to quick-fix options and continue to educate themselves on organic systems, she said.



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