Reprinted from December 2012 • Vol. 42, No. 12

by Gary Zimmer

Editor’s Note: This is part two of a two-part article on soil health and minerals. In part one, Zimmer discussed the role of minerals in achieving soil health and the importance of using balanced minerals from soil-life-friendly sources. In this part of the article on minerals and soil health, Zimmer focuses on research and farm demonstration stories.

Soil health, soil tilth, and soil fertil-ity are all big picture words. They try to give a vision of a proper functioning soil. I am convinced that many biological farmers have put calcium as king toward achieving soil fertility. It is certainly not the only thing, but as I stated in my last article, getting high plant levels of calcium is certainly a soil health/soil fer-tility measurement. You also need great soil tilth, and calcium helps this happen. This certainly describes a biologically active soil with a great balance of soil life.

I stood on a farm in Australia a few months ago, an 800-cow grazing opera-tion in South Victoria. The farmer’s nor-mal fertilizer program until a few years ago was urea, lots of it (up to 300 units of N per year) and potassium chloride. The farm had shallow, light soils that were limestone-based. Dig down a foot or less and you’re into high-calcium lime. The farmer was having problems growing legumes and ‘fog grass’ as he called it was invading. (Fog grass, or velvet grass, is

an unpalatable grass that is an indicator of poor soils.) In order to try a different way to address his pasture problems, he switched to a biological approach. He reduced purchased nitrogen inputs, as that was also a cost concern for him, and he added humic acid to his nitrogen. He also switched from KCl to K2SO4 and K-mag — these soils are low in magnesium and using K-mag should help. He mixed his potassium sources in a humate base with boron, zinc and other minerals added.

Now, one year later, the fog grass is gone, legumes are back, and earthworms have reappeared — the farmer said he had not seen them for years! The soil was low on “smell” but the structure looked great. In addition to improvements in the soil, the farmer also saw improve-ments in his pasture. Because the pas-ture switched from being all grasses to a grass-legume blend it was hard to tell from feed tests if plant calcium, phos-phorous, magnesium or other minerals were changed. But the quality of the pasture had improved, and the farmer was amazed that he saw all of these posi-tive changes just by changing minerals on his pasture. The Australian farm only produces forages, so they need to pur-chase what’s missing. By getting those nutrients in the forages, there is less need to buy them, and now they’re in a more digestible form.

The plant tissue test is the farmer’s “report card” of how well his soil fertility,

or nutrient exchange program, is work-ing. An ideal level of nutrients in the plant sample needs to be determined and the soil nutrient additions adjusted ac-cordingly after many samples are taken to establish a base level. In addition, cow grazing management, or in other words how the farmer uses the cows to harvest the forage, needs evaluation. The better we do with these the more production we get, and the need to supplement the animals with expensive grains and min-erals is reduced.

I could say just do the minerals right and all will be fine; it is certainly a start-ing point and an easy step to make. I would estimate that 80 percent of the 5,000 farmers we work with here at Mid-western Bio-Ag mainly change minerals, or at least start there. For dairy farm-ers, adding grass to alfalfa and tighten-ing the rotation (going from 4-5 year

Soybean plants from side-by-side plots: Plant on the top is from the conventional plot; plant on the bottom is from the plot treated with minerals.

Corncobs from plants treated with minerals.

Minding MineralsStories From the Field

Reprinted from December 2012 • Vol. 42, No. 12

hay stands to 2-3) is another key step. This makes manure management easier and greatly reduces inputs for growing corn. We would add a balanced calcium source with sulfur and boron to their hay and also apply a balanced, more earth-friendly fertilizer to all their crops — this takes them a long way.

A traditional corn/bean farmer we started working with this year in Illi-nois has also seen really positive results just by changing his minerals. He’s been planting no-till and following a corn/corn/bean rotation for years, applying 175 pounds per acre of potash and 125 pounds per acre of MAP or DAP (which source of P he uses varies depending on availability). He’s never used soil cor-rectives and never applied calcium or trace minerals to any of his fields. This year he applied 425 pounds per acre of Bio-Cal (a Midwestern Bio-Ag propri-etary product that’s a blend of different calcium sources) with some sulfur and boron. Just by changing his minerals, adding more calcium, sulfur, and boron, the farmer saw a big change in his corn and his bean crops.

He left some check strips on his fields, and the difference in ear fill on his corn was really noticeable. It’s been a dry year, and a lot of farmers have had poor pollination and poor tip fill on their corn. This farmer had 15 per-cent better kernel counts and better tip fill on the corn where he added a little calcium, sulfur, and boron (see photo at left). His soybeans also showed big improvements. The fields without the extra minerals had about 40 to 60 pods per plant, while the fields with the added minerals had 80 to 90 pods per plant (see photo). As I’m writing this article, the corn is due to be harvested in a week, so the yields aren’t known yet, though the farmer estimates he’ll get an extra 20 bushels per acre on the fields that received extra minerals. The soybeans yielded 58 bushels per acre on the conventional fields, and 63 bushels per acre where Bio-Cal with the extra minerals was added.

For the Midwestern corn-bean farm-er, zone tillage is a hot topic right now, and mineral management is a big part of being successful. Zone tillage is a great tool for fast change with minimum dol-lar input. Switch the fertilizer, use a car-bon-based source, and concentrate ap-plication in the zone, which also makes a better soil to put a seed in. Adding

calcium to this system is also important but due to many rented acres, different sources may need to be used, ones that give the fastest, shortest-term results for the dollar. One way or another, our big-gest change to make farmers practicing zone tillage into biological farmers is to change the minerals used, and their sources.

Of course, just changing minerals certainly won’t fix all of the problems on your farm. There’s also soil structure, organic matter, and biology to consider. But changing the source of minerals and adding a balance of all minerals can go a long way toward improving soil health and crop health. It’s a good first step to

take down the road to being a successful biological farmer.

Gary Zimmer is the author of Advancing Biological Farming, a sequel to his earlier book, The Biological Farmer, both published by Acres U.S.A. He is also an organic dairy farmer, an accomplished speaker, a sought-after farm consultant and president of Midwestern Bio-Ag, a biological farming products and ser-vices company. For more information visit www.midwesternbioag.com. Zimmer, along with Leilani Zimmer-Durand and Ellen Polishuk, will be teaching a pre-conference workshop, “Biological Farming School,” Dec. 4-5, 2012 at the Acres U.S.A. Conference & Trade Show in Louisville, Kentucky. For information on the conference, visit www.acresusa.com or call 800-355-5313.

Soil Mineral Balance & Plant HealthPlants depend on the soil to get the minerals they need. If there is a deficiency

of soil minerals, plant health suffers. But it’s not just about meeting minimum re-quirements for plant growth — the balance of minerals in the soil also affects plant growth and plant health. Plants that grow in imbalanced soils will show a number of problems, such as poor growth or increased susceptibility to insects or disease.

When the nitrogen cycle is out of balance from applying a lot of soluble ni-trogen, it causes problems for plant health. When there is an over-abundance of soluble nitrogen in the soil, plants focus their resources on growth and not on defense — resulting in large plants that are poorly able to defend themselves against insect attack. In addition, plants that take up extra nitrogen tend to have a lot of incomplete proteins, or free amino acids, in their tissues. Insects like to feed on free amino acids. They’re easier to digest than complete proteins. Some sap-feeding insects, like aphids and spider mites, not only prefer plants with higher levels of free amino acids, they grow and reproduce better on those plants.

An imbalance of trace minerals in the soil also causes problems for plant health. Dr. Larry Phelan of Ohio State University has done a lot of research on soil organic matter, mineral balance and plant health. In one of Dr. Phelan’s stud-ies, he looked at the balance of iron, zinc and boron on plant health. Soybeans were grown in hydroponic solutions with various levels of these three minerals; some solutions with a balance of iron, zinc and boron, and other solutions with an imbalance of these minerals. The plants were then introduced to different insect pests. Mexican bean beetles that fed on plants grown on an imbalanced mineral solution were 45 percent larger than those that fed on a balanced solution plant. In addition, the levels of free amino acids were five to 10 times higher on the plants that grew in the unbalanced solutions, suggesting that the deficient plants were also more attractive to insects. In contrast, when plants are grown in soils with an optimal balance of these minerals they have both excellent growth and good resistance to insects and disease.

Mineral balance in the soil is directly related to plant health. When plants are growing under less than optimal soil conditions, there is a trade-off between allo-cating resources to growth or defense. When the soil is balanced and mineral levels are optimal, plants can allocate resources to both activities. Not only is balance in the soil important for plant growth and health, it also impacts the entire soil food web. By using a balance of all of the minerals needed for plant growth, attaching your minerals to carbon, not overdoing soluble sources and promoting organic matter, it’s possible to grow healthier plants that don’t rely on chemicals to survive.

— Leilani Zimmer Durand

Leilani Zimmer-Durand works closely with Gary Zimmer at Midwestern Bio-Ag and heads MBA’s research program.

Reprinted from December 2012 • Vol. 42, No. 12

Importance of InputsA large wholesale vegetable grower contacted us this last spring for help with his

produce. While he was getting OK yields he felt that his regime of weekly sprays for disease and pests was an indication that something wasn’t right on his farm. He wanted help reducing the pest and disease pressure on his farm. As he was only a few weeks from planting at the time we got involved with him we were not able to do much besides change his fertilizer inputs and add some calcium to his soils in the form of BioCal. On the mineral side we changed from using urea, potassium chloride and a mixture of DAP and MAP to using ammonium sulfate along with a stabilized urea product, potassium sulfate and K-Mag, and a mixture of MAP and rock phosphate. Along with this we included some calcium in the fertilizer and bal-anced trace minerals tied to carbon.

When the opportunity arose to go and check on how he was doing this summer, which has been a challenge for many growers, I was pleased to find him upbeat and optimistic. I spent some time looking at his crops before we talked and noticed that they looked healthy and that he had installed irrigation to deal with the drought conditions, but I wasn’t sure what he was doing to control disease and pests. When we were talking I asked him what his disease pressure was and he replied that he had gone from spending $600 per acre spraying all his crops every week with fungi-cides, to only applying a fungicide to one of multiple watermelon fields once during the growing season. He asked me how much of this change in crop health I would attribute to our fertilizer program. I told him I’d say it was 50 percent weather, 25 percent our program, and 25 percent other factors. “What if I told you that I was overhead irrigating the melons?” he asked. This is of course something that is ill advised with cucurbit family crops, but it was his only option this year because of the drought. Because overhead irrigation usually increases disease problems, I told him that I’d change my answer to 30 percent weather, 30 percent our program, and 30 percent other factors. “That’s interesting,” he said, “considering I’ve been over-head irrigating night and day and walking through the crop while it’s wet as well.”

You might be wondering what is going on here, and how just a simple change in fertilizer can have such a huge effect on plant health. It is important to realize that for every small change we make we can affect multiple aspects of both the soil and plant health systems. For instance, simply by changing from potassium chloride to the sulfate form we stop leaching out calcium. This in turn can allow soil structure to improve, as well as being less hard on soil life, allowing it to flourish more and in turn cycle more nutrients through the soil system and make them plant-available. When we change multiple inputs, we can get a stacking effect. Will we see such dramatic changes as those in these examples every time? No, but over time chang-ing to more plant- and soil-friendly fertilizer sources will always make a substantial contribution and change to soil and plant health.

— Allen Philo

Allen Philo has worked as the field operations manager on a large organic vegetable farm and is currently the specialty crop consultant for Midwestern Bio-Ag. He can be reached at allenp@midwesternbioag.com.

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