Horse people hate clay. As far as horse people are concerned, clay is right up there with ticks and chiggers. When it gets wet, it sucks your boots off and makes you fall face first in the mud. It sticks to our Friesians’ and Clydesdales glorious feathers and turns into brick balls that have to be cracked off the hair with pliers.
Rejoice Horse People. I’ve found a use for clay.
The smallest particles of clay are called the “clay colloid.” These particles are sort of plate shaped and have a negative electrical charge.
Visualize a Wal-Mart parking lot; angular and with a surface covered in parking spaces. That’s a clay particle, a microscopic Wal-Mart. Only on clay, the parking spaces are called “exchange sites.” When there are no shoppers, or minerals, all the parking spaces, or exchange sites, are occupied by hydrogen. Hydrogen is non-nutritive and has a positive charge. That’s why it was attracted to the clay. When it’s hogging all the exchange sites, it makes your soil acid and nutrient deficient. That’s what soil acidity, or low pH is all about – too much hydrogen.
Wal-Mart clay is having a sale and the early bird shopper, Calcium, shows up. Calcium has a strong positive electrical charge and bullies some of the parking spaces away from weaker hydrogen.
The next positive mineral to arrive is Magnesium. It bumps some more hydrogen out of the parking spaces.
Hey look, here comes positively charged Potassium. So long Hydrogen. Next comes Sodium. A few other positively charged elements straggle in.
Calcium however, has called in all its relatives and the parking lot is getting really jammed! Calcium pulls out is superior positive electrical charge and starts bullying the weaker charged elements right out of the parking lot! When more Potassium starts showing up a fight breaks out and other elements begin to scatter.
This is the beginning of soil imbalance, and sometimes, similar scenarios result in wars between nations, with about the same results only on an invisible scale. But it’s massive, if viewed on a global scale. Modern Agriculture doesn’t pay much attention anymore.
These positively charged minerals are called cations. They are some of the heaviest hitters in both animal and plant nutrition. Calcium for the soil was once thought of as only a means to modify soil pH, but Albrecht established it as the premier nutrient because of its profound importance in so many metabolic activities.
The positively charged cations tend to “persist” or stay put in soil and resist leaching because the negative clay component of the soil attracts and holds them. But as you well know, competition at Wal-Mart can lead to shootings and fatal stampedes. Too much of any one cation is at the expense of the others.
Albrecht devised a method for assuring that the cations are present in balance on the soil colloid – that is not too much or not to little of any one of them. This method is called the Cation Exchange Capacity, or CEC. The CEC of any given soil varies, and so the ratio of cations to one another varies from soil to soil. Some Wal-Marts have bigger parking lots than others.
The relevance of the CEC, from one perspective is that if your soil CEC indicates your soil can only handle say, 400 pounds of additional calcium per acre, and your extension agent tells you to put on 2000 pounds “to correct the pH,” all heck’s going to break out in the parking lot. The clay will get choked up with calcium at the expense of other cations, and the end result will likely be a shock to your hay analysis. That could come in disguised as a copper deficiency, for too much calcium ties up copper and other elements. If you didn’t know about this stuff and your hay report said not enough copper, you might be tempted to add more copper to the pasture next round and supplement the horses with copper sulphate in the meantime. Yes, the horses need the copper, but you’re adding fuel to a thousand fires if you don’t address the real source of the copper deficiency in the pasture, because the copper is out there fabricating some other nutrient in the grass for your horse. The grass’ metabolism is short circuited, and that’s cheating your horse out of balanced nutrition.
Maybe your copper imbalance didn’t come from too much lime, but a bad copper to molybdenum ratio. What do you do – add more copper to overcome the moly? Or add some other mineral that’s deficient whose addition will also bring the excess moly to heel? Too little copper in the grass plants will short circuit the grass’ immune system, inviting in all sorts of bugs and diseases to attack its weak cell walls, and so if you’ve got a valuable crop out there, prepare to drag out the toxic chemical rescue. Copper has limitless activity in your horse as well, including strengthening the gut lining, so if he’s getting adequate copper, he may be able to quit taking the ulcer medicine – hottest new thing on the market. Is it really “heliobacter,” or is a weak gut lining caused by a hidden hunger?
Then you’ve got the drifters, the negatively charged minerals that don’t hang around the clay Wal-Mart in the presence of a lot of rainfall or irrigation. But since they’re negatively charged, a positive cation might like the anion better than the clay and latch onto it like a one night stand and party down…down into the subsoil and out of reach of the plant roots. Sulphur, phosphorus and nitrogen are anions. That’s one way of correcting an over abundance of some element like calcium or potassium in the soil.
Anions will almost always have to be replenished on a regular basis, in the face of crop use, rainfall and irrigation.
I’m not up to speed on positives and negatives in the mysterious world of trace elements, but some of them leach, like boron, and some of them persist.
Like the population of a complex metropolis, minerals interact with one another and the rest of the soil life web, forming compounds, changing with the seasons, either being contributing citizens of the soil community or perpetrating “crimes” in impoverished soil, the equivalent of a plant slum. A certain level of one element may be necessary, too much can be toxic to plants. Too many police on the payroll is the cost of too many gang fights in the community. When everything is in harmony, the rest of the community is free to do its good work without disruption.
Does this sound familiar? Haven’t you heard pretty much the same story when it comes to horse nutrition? The minerals have to be there and they have to be in balance, otherwise, the exquisitely complex metropolis of living organisms called your horse will have much civil unrest. If the horse is ingesting the grass equivalent of war refugees, the displaced population is soon going to grow to the point where the horse’s resources are overwhelmed.
The science that governs the interactions between minerals, clay, water, air, humus and living soil organisms is to me, as complex as the workings of the universe and I don’t pretend to have the least grasp of it. This section is only meant to sprinkle a scant bit of entertainment on the subject, but at the same time, encourage people to begin thinking about soil mineral balance in the role of producing nutritious hay for horses. The practice of giving supplemental minerals to horses is probably unavoidable, but hopefully you are beginning to see the “trickle-up” effect of putting the minerals where they’ll do the greatest good, at the very beginning of nutrition fabrication.
For the next few posts, I’ll probably tinker with drawing comparisons between some soil samples and hay samples.
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