Archive for March, 2011

Our Farm’s Soil: Where We Are and Where We Want to Be

Here’s where we are as of November 2010:

Soil Test Results

And here’s where we want to be:

a. Organic Matter:  at least 5%

b. Calcium: close to 3,000 pounds per acre

c. Magnesium: close 430 pounds per acre

d. Potassium: 150 to 200 pounds per acre

e. Sodium: 40 to 130 pounds per acre

f. Phosphate (P2O5): 400 pounds per acre

g. Sulfur: around 100 ppm

h. Boron: between 2 and 4 ppm

i. Iron: at least 150 ppm

j. Manganese: between 40 and 50 ppm

k. Copper: around 10 ppm

l. Zinc: around 20 ppm

Organic Matter

Our organic matter, currently less than 2%, needs to more than double to 5%.  We’re trying hard to protect our organic matter by mowing and mowing and leaving all clippings on the field.  We’ve done this for the past two summers, and we can see small but promising signs that soil microbes and earthworms are returning.  When we finally do get animals, our organic matter should start to climb sharply from the impact of hooves stomping plant matter into the soil and from the microbe-rich manure.  Can’t wait!

Calcium – Add Lots

Typical of soils in wet climates, our soil badly needs calcium.  Great pasture has at least 3,000 lbs of calcium per acre available to plants.  Our best field has under 1,400 lbs, so we have a long way to go.  We bought a fertilizer named TRIO, a.k.a. carbonized lime.  We’re going to spread it at a rate of 200 lbs per acre this spring and again this fall.  It has about 30% calcium, microbials and humic acid, which is nice carbon for the soil.  We’re excited to see what this can do for our land in terms of calcium, microbes and organic matter.  Because we don’t want to get outside the ideal base saturation range for calcium (more than 70%), we have to go a little slow.  I wrote about that here.

Magnesium – Add None

With sandy, low-organic matter soil, our exchange capacity is around 4 and 5.  This is really low and means the soil won’t hold many nutrients.  We want to eventually have close to 430 lbs per acre magnesium.  But our magnesium values, in the low 200s, are maxing out our base saturation percentages for magnesium.  We don’t want more than 20% base saturation for magnesium, or the soil gets unbalanced, and problems, such as magnesium locking up other needed nutrients and the soil getting too tight and non-porous, start to occur.  Because of this hazard, we’re not going to apply any magnesium.  We might never need to.  If our organic matter levels come up, it might make more magnesium available to plants.  Magnesium doesn’t leach out of soil in wet climates as badly as calcium does, so we might have plenty of magnesium anyway.  We just need more organics to make it available to plants.  We’re aiming for the ideal calcium to magnesium ratio of 7:1.  This ratio, with adequate organic matter, gives the soil nice tilth, meaning it’s neither too loose (compacts easily) nor too tight (water and air can’t get through).  So 430 lbs per acre with 3,000 lbs per acre calcium gives us this nice ratio.

Potassium – Add a Little, and be Careful

All fields except our Middle one are a little short (below 150 lbs per acre) on Potassium.  We plan to up the Potassium levels by spreading composted manure.  We’ve been getting free horse manure from nearby horse barns and composting it in big piles.  I know it has lots of potassium because I put a lot of it in our veggie garden and our potassium levels are now way too high (argh!).  The microbes in the composted manure will be good for our fields.  I’ll definitely get an analysis on the compost before I apply it so I don’t repeat the veggie garden mistake.

Sodium – Add a Little

We need at least 40 lbs per acre, and some of our fields are short.  There are wonderful sea salt fertilizers available out there.  Coming from the sea, they have nice amounts of all micronutrients along with 30% sodium.  We need massive help with micronutrients anyway, so we plan to apply one of these fertilizers.

Phosphate – Some Fields Need it

Two of our fields consistently show high amounts of phosphate while the other two don’t.  This might give a clue to our farm’s history.  The two fields with high levels are close to the house and outbuildings.  The previous farmers might have spread manure in these two fields so they wouldn’t have to transport it to the farther fields.  Who knows?  We’ll definitely need to apply soft rock phosphate to our East and West fields.

Micronutrients – Add a Lot

Boron, Copper and Zinc are in the worst shape, and some fields need iron and manganese too.  We plan to apply Boron, Copper Sulfate and Zinc Sulfate to our fields this summer.  These nutrients are needed in small quantities, but they’re essential for plant and animal health.  We’ll probably apply Iron Sulfate and Manganese Sulfate next year.  We’ll apply all of these very conservatively because with levels testing this low, they might just be tied up by something, such as lingering herbicides or mineral imbalances.

Why All the Trouble?

Our goal is to produce highly nutritious, very tasty food.  Taste and nutrition come from the soil.  We’re hoping that our current efforts and fertilizer expense will pay big dividends in the future such as little to no animal disease, fast-growing animals, high meat quality that attracts customers, and increased human health as well.

Unsustainable Chemical Fertilizer: Ideology and Reality Collide

Recently I’ve been alarmed at what I read on sustainable farming blogs and articles.  I’m seeing more and more farms talking about foregoing all chemical fertilizer as a wise decision, and I see a lot of blog comments saying organic farms can “auto-fertilize” themselves.  There seems to be a growing ideology out there that sustainable farming means “no inputs” and that organic farms, especially those with livestock, should be a closed system requiring zero fertilizer for their soil.

I don’t want to ponder on the ultimate definition of “sustainable” because everyone seems to have a different opinion.  What I want to do here is set the record straight on chemical fertilizer and discuss how uninformed disdain for it can lead to unfortunate results on our farms, especially farms that raise 100% grass-fed animals on depleted soil.

The two major complaints about chemical fertilizer are its propensity to kill soil life and the fossil fuel energy-intensity that’s required to make it.  This is true for some chemical fertilizers, but not all of them.  Anhydrous ammonia and muriate of potash (potassium chloride) are probably the worst.  They do hurt soil ecology.  Since we’re practically begging soil life to come back to our farm, we would never use these two.  But we will use many of the other chemical fertilizers.

If you find yourself objecting to the word “chemical,” understand that all minerals necessary for life are chemicals too.  Our farm is in desperate need of calcium, so we’re going to apply calcitic lime.  Calcium is a chemical, and calcitic lime is a chemical fertilizer.  Fertilizers like this don’t harm soil life at all.  Instead, they help the soil ecology thrive by bringing the soil’s mineral components and pH into balance.

Regarding energy intensity, it’s true that a great amount of fossil energy is used to make fertilizers, especially nitrogen.  In very healthy soil with at least 5% organic matter, nitrogen is cycled naturally from the air and is made available to plants via soil microbes.  This natural cycle takes years to come back in depleted soil.  If I were growing a nitrogen-hungry crop like corn on our worn-out, 1.5% organic matter soil, I would need nitrogen fertilizer.  I would apply one that’s harmless to soil life, such as ammonium sulfate.  It’s unfortunate that ammonium sulfate requires fossil fuel to be made, but it does.  For our farm, our top goal is to grow nutrient-dense food, and given our soil situation, that can’t happen right now without fertilizer.

Many farmers have swirled these arguments around and around in their heads and have come to different conclusions.  Some have decided the best option is to forego all fertilizer except the manure that comes from their own animals.  This is admirable on the surface.  However, there are problems with manure coming from poor soil.

There’s no getting around the reality of depleted soil.  Soil lacking in nutrients and/or deficient in organic matter will not provide what’s necessary for plant quality.  Plants lacking in nutrients won’t completely feed animals and people.  Animals, especially 100% grass-fed livestock, will not do well grazing on worn-out soil because this soil is their sole food source.  Birth weights, milk yields, and meat quality will all be sub-optimal.  Unfortunately, many farmers are convinced that their animals’ manure will solve the problem.  Manure does indeed help with increasing organic matter.  However, when it comes to nutrients (chemicals) like calcium, magnesium, boron, zinc, etc., manure will not help.  If the animals’ feed doesn’t have good quantities of these nutrients, the manure won’t either.  The soil situation will get worse as meat and milk containing what’s left of these nutrients are sold off the farm, and the farmer, still convinced that manure will solve the problem, adds no fertilizer to replenish the soil.

This situation is called “organic by neglect”.  The farmer’s ideology is held intact, but the soil’s mineral content declines even further, and everything the soil supports – pasture quality, animal health, farm profits – sadly deteriorate.

The “no fertilizer” ideology bumps up against the reality of burned-out soil.   We have hundreds of thousands of acres of depleted soil in this country, but fertilizing thoughtfully and caring for soil life can bring them back.  So if you bad-mouth chemical fertilizers, please make it clear which ones you’re talking about.  Some of them deserve the put-down, and some absolutely do not.  Let’s also keep each other from going down the path that favors ideology over soil quality and animal health.  After all, what’s more sustainable to life than living, healthy, mineral-rich soil?

Part of Kelly the Kitchen Kop’s Real Food Wednesday and Food Renegade’s Fight Back Friday.


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