Wednesday, May 29, 2024

Soil Compaction -- cattle will help to heal it!

  CONCEPTIONS Beef Cow-calf newsletter                  Jan-Feb 2023 

A recent (January 2023) article in Stockman Grass Farmer carries an article by Mississippi beef, pork and poultry rancher Ben Simmons entitled “Biology supersedes Chemistry.”

His lead paragraph says “You can have mineral nutrition perfectly balanced on a soil analysis and yet will not grow healthy plants on that soil, as long as you have poor biology.”

Soil biology is essentially three forms.    We are all familiar with worms; nematodes and dung beetles perform related recycling functions.   There are also bacteria and fungi.    The optimal proportion of bacteria to fungi is 1 to 1.    These soil biology forms transport nutrients into the growing plant roots.

Compacted soils have little effect on bacteria (which are anerobic) but can seriously harm the fungi (which are aerobic, ie, they need oxygen) as well as worms and nematodes.    The better soil will have “structure” (air pockets and water infiltration channels) which is built up by root masses (alive and growing or dead and decomposing) and incorporated manure and crop fiber residues.   These are called “high organic matter” soils which capture rain, whereas a tighter, compacted soil (even if the surface is tilled) will allow rain to runoff, often eroding topsoil with it as it flows into your drains and out to streams.

While chemical fertilization and weed suppression generally insures us a crop harvest, these practices can inhibit soil biology and thus lower the residual fertility of your soil.    Over history the use of chemical herbicides and pesticides has grown in tandem with longer-maturity crop varieties, leaving no time for the planting of “green manure” cover crops.    Leaving harvested fields bare of growth over the winter can starve and even freeze soil biology of all forms, while free carbon breathes out from the soil and enters the atmosphere.    (Ten times as much green house gases are released by open soils as are produced by all our ruminant livestock!)    If we analyze crops grown on soil treated this way, you find the nutrient density to be lower as our yields have gotten greater. 

When you hear that term “empty calories” being applied to our modern grain production, the key ingredient in most processed consumer foods, the losses of soil biology are the most direct explanation; plants lack the nutrients they bring to the root zone, especially from fungi.    (Both animal and human health suffered from monocultural crop production dependent on chemical fertilization and propogation.     Look at how the “Covid” situation drags on!)

What our animals can contribute to improved soil biology and resulting fertility

Because you have animals, some of your land benefits from incorporation of their manures.    However, to get the “whole enchilada” of soil stimulation and health from animals, you need to graze every field at some time of the year;  not just manure, but urine, enzymes, nasal drizzles, even shedded hair, pass microscopic bacteriology onto (and if not compacted, into) the soil and contribute humic substances that stimulate the growth of mychorrizal fungi.    Short periods of intense grazing (spring cool-season green vegetation, or fall planted covers including some that regrow in spring) can provide some cheap feed for your animals at times when the soil is most receptive to animal effluents.    These same fall and spring covers keep root masses growing in winter, thus helping to keep soil bacteria and “companion livestock” alive.    In some synergistic way, the animals’ total biological exchange aids soil health.    All that is required are permanent corner posts and temporary fence you can roll out and retract between crop growing seasons.

Mob grazing large numbers of animals on degraded soils in places like Africa and the USA deep south where monocultural cotton and tobacco depleted soil fertility, has proven able to bring those acreages “back to life” able to support desired plant growth, sequester carbon, and most importantly, capture rainfall into the root zone.  ( Refer to Allan Savory, whose Holistic Resource Management has guided noted USA cattlemen like Greg Judy to increased cattle production.)

Soil compaction occurs in many ways:  from driving across wet soils in cool seasons;  from over- application of anhydrous;  from deep plowing that turns furrows completely over, burying any green growth or crop residue into an anerobic layer that does not decompose;   from hard rains onto barren or tilled ground, promoting runoff;  from continual growing of row crops that leave large bare spaces between rows subject to evaporation and excessive warming from the sun; from not growing a cover crop in the winter to replace organic structure consumed by each row crop.

As for pastures, the overgrazing of the more desired species by “set grazing” (instead of regular rotation of paddocks to prevent chewing the green growth below a 4” to 6” height that insures photosynthesis for regrowth) not only will degrade the pasture plant mix (opening up space for weeds to enter) but also leads to compaction from the warming of the soil similar to the effect in row crops.    Studies prove that your animals can harvest 50% more plant growth across the grazing season if paddock divisions are established and frequently rotated.

It used to be common to see beef cows gleaning the wasted corn and residue stalks after corn harvest.     Combining usually leaves 2 bushels or more per acre on the field surface.    Even if all you do is roll round baled hay out across crop residues for winter feeding, you will note greener color under the path of the bales the following spring, and a healthier crop that summer.    Let your animals work harder for you.     It will save you  $$  and increase both calf and crop yields.

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