I grew up in a time when we all believed we were smarter than Mother Nature. We all subscribed to the notion of ‘Better living through Chemistry’. We could isolate any question and address it through the scientific method. We had firmly established that we as human beings were separate from nature and that we were above nature. We ruled the Earth. We could control weeds in our fields with a simple, safe chemical. Our scientists assured us these chemicals affected nothing else besides the target weeds. I watched my weed science professor drink Atrazine to assure us of its safety. He long since died of lymphoma. We could eliminate parasites from our livestock with a simple pour-on chemical.
There was only one problem.
We were mistaken.
We found we could also eliminate over 800 soil organisms with that same pour-on. We have found hundreds of manufactured chemicals touted as being safe are far from it. We have found out we do not rule the earth.
As the years have gone by we have been brought back to the reality that we are a part of nature, not apart from nature. We cannot isolate our actions from the eternal ripple effect. The reality of Mother Nature has come home to roost. Thermodynamics says for every action there is an opposite and equal reaction. That is a law of physics and is generally related to concepts of energy and force. Biology is infinitely more complicated than physics, the reaction is not always opposite and sometimes it is not remotely equal.
Everything is connected at the physical, chemical, and biological levels. The response to our actions in the ecosystem are not simple and linear. They are multidimensional and may either gather additional energies through synergy or they may rapidly fizzle to nothing as all energy is rapidly expended.
I went to college and then graduate school and became well indoctrinated in the methods of reductionist science. Even though I worked at a place called the University of Missouri – Forage Systems Research Center, the longer I was there the more I realized I knew and understood less and less about the soil-plant-animal interface. We designed and executed research projects geared towards development of ‘forage-livestock systems’. After 22 years 3 months on the MU faculty, I came to the realization of the validity of a certain piece of Eastern philosophy that I have carried with me ever since that time.
‘Do not speak an answer until you understand the question.’
What I learned in two and a half decades of academic agricultural research was that I didn’t understand the question. Sadly, I don’t think many of my colleagues understood the question either.
So what is the question? Unfortunately, it is not so simple as Douglas Adams presented it in ‘Hitchhikers Guide to the Galaxy’ and the answer is not so simple as ‘42′.
The question as I see it today is where do we as a species fit into the linkages of the total ecosystem. That is a large question beyond the scope of my time here today. That is the cop-out way of saying it is really beyond my scope of knowledge and understanding, but I keep working on trying to figure it out.
Today, I want to look at a small piece of that overall linkage. That is, where do we as land managers have opportunity to control, manipulate, or tweak the linkages among the soil-plant-animal interface to benefit ourselves as individual farmers or ranchers but also to leave an intact planet for our descendants.
I have spent most of the last 35 years working in the realm of grazing and my favorite genre is perennial pastures whether that be as seeded pastures or native rangeland. Even though I grew up a crop farmer, not a livestock farmer, I have moved farther and farther away from any agriculture that involved disturbing the soil. Coming back into the crop circles (no pun intended!) via the no-till farming movement has brought me back to the notion that crop farming and soil health can occur simultaneously. That is a real positive in my view.
Because of the destructive nature of tillage on soil structure, biological life, and the propensity to create soil erosion, the removal of all conventional tillage from farming systems is one of the first steps towards creating a more sustainable food system for our species. Elimination of tillage is the first step towards restoring biological life to the soil. Permanent grasslands are the most sustainable form of food production in my view largely because of the elimination of tillage. Fortunately, we could exist entirely on an animal-based diet, so we could get everything we need from these grasslands.
The second critical step towards restoring overall ecosystem health, humans included, is the elimination of the use of all the x-cides in our operations. With all the products that are designed to kill something – herbicides, fungicides, insecticides, parasiticides – how could that possibly be good for us or the world around us? Remember, for every action there is a multidimensional response and, for the most part, we really have had very little idea of the degree or direction of those responses.
There are certain aspects of the soil-plant-animal relationships of which we do have a decent understanding. Those are the areas where we need to focus our management attention as that is where we can make the greatest progress. These are all relatively simple concepts, but often overlooked because they are so simple.
Most cropland soils in the US have undergone severe organic matter depletion in the last century. Both graziers and no-till farmers share the goal of restoring organic matter to pre-Industrial Revolution levels. There are few key concepts to keep in focus.
1) The more above-ground growth you can create, the more below-ground growth there will be. Soil organic matter is build from the bottom up, not the top down. I am not discounting the critical importance of plant litter or crop residue on the soil surface. For purposes of soil protection and enhancing the water cycle, surface litter is of utmost importance. But most stable organic matter is created from the decay of root material, not surface litter.
2) We always say that what goes on below ground is a reflection of what is going on above ground and vice versa, but it is rarely a 50:50 correlation. Perennials in general put more CHO flow below ground than do annuals. Why? Because long term survival is dependent more on roots and crowns than on elongated shoot growth. Annual crops have no need to plan for long term survival, so annuals can put more energy into top growth. The drier the environment, the greater the percentage of CHO flow from ongoing photosynthesis to root growth and storage organs.
Relatively speaking, perennials will build more deep profile organic matter for you while annuals proportionally can contribute more to the litter layer development. The historic problem with conventional tillage is we destroy more organic matter than we can develop annually even with high crop yields. Take tillage out of the equation and building organic matter becomes a much more realistic proposition.
3) The combination of annual cover-crops seeded into perennial pastures can provide both deep root development and rapid accumulation of surface litter. Timing of seeding of the annual crops to be least competitive with the perennial forage base and vice versa is a key component for this strategy. With improper timing, both the perennial and annual can suffer and no added value is gained with the annual crop interseeding.
4) Livestock grazing of no-till cover crops and crop residues has several benefits including creating an additional revenue stream, accelerating the rate of nutrient cycling, and inoculation of additional microbes to the soil via salivation and manure excretion. Annual cover-crops offer the grazier opportunities to provide high quality forage for high performing livestock classes at a time in the year when they might not typically have it if using only perennial pastures.
High stock density grazing can be used to terminate the growth of a cover crop prior to seeding the next row or small grain crop. This is the time when we may want to indulge in grazing part of the crop and trampling the reminder to create a mulch layer to trap water for the newly seeded crop. There may be rare instances when we actually graze the cover crop so severely there is little to no residue remaining. If the seeded crop is susceptible to particular soil insects or slugs, we might need to minimize the protective cover. When these issues may arise is when using longer crop rotations with more years of perennial pasture may be particularly valuable.
5) The most effective way to keep the pasture solar panel functioning at top efficiency is to allow it to grow to the high Phase 2 level, which generally corresponds with 4 to 5 1⁄2 leaf stage, and then grazing it at about 50% utilization. Sometimes a little more and sometimes a little less, but a 50% utilization rate generally leaves the pasture in a low Phase 2 state. This degree of grazing will cause a certain amount of root sloughing, but active root growth returns fairly quickly.
This is what is generally referred to as pulsing the pasture and is a technique to stimulate photosynthetic activity. While generally done several times a year with perennial pastures in high rainfall or irrigated situation, pulsing can also be used with annual pastures to extend the productive season on the annual pasture crop. The greater the diversity of your cover-crop mix, the more beneficial pulsing the solar panel is more likely to be.
6) Crop farmers frequently have concern about potential soil compaction from grazing livestock on their fields. Many have the idea that if they spread the livestock out over a larger area, there will be less compaction occur. That is exactly opposite of what actually happens. Grazing livestock at a low stock density allows them to travel over greater distances every day resulting in more hooves hitting the ground. As this force is delivered over a longer period of time, the soil has less opportunity to recover from the pressure and compaction builds.
One of the classic studies of soil compaction relative to grazing methodology was conducted by Michael O’Sullivan at the Johnstowne Castle Research Center in Ireland in the late 1970s. This study compared the daily travel distance in either set-stocked or rotationally grazed paddocks. What they found was cattle in set-stocked pasture consistently traveled a greater distance than did cattle concentrated in smaller paddocks. The shocking part of it was once feed supply became limiting in the set-stocked pasture, the daily travel distance was 4X greater than in the rotational paddocks.
Since degree of compaction s determined by the combination of soil type, soil moisture, and physical force applied to the soil, increased travel distance means more total hooves hitting the ground every day. In the grazing world, the potentially compacting physical force applied to the soil is hoof beats.
Recovery from soil compaction is through biological activity and the soil and freeze-thaw process. The more biologically active the soil, the more rapidly the soil will recover.
The deeper we delve into the soil-plant-animal interface, the more we begin to understand that we are all inextricably linked in the web of life. We need to think in terms of multidimensional response to our management decisions rather than the overly simplistic ‘If I do this, I will get this.’
Going back to that Kung Fu wisdom, seek to understand the question before you speak the answer.
This article is a result of soil health and grazing workshops KAWS held in 2018 across the state. Funding for the workshops was provided by the North Central Extension Risk Management Education Center and the USDA National Institute of Food and Agriculture. Project partners include the Kansas Alliance for Wetlands and Streams, NRCS-Kansas, Kansas Water Office, K-State University, Kansas SARE, No Till on the Plains, Kansas Dept. of Health and Environment, nine Watershed Restoration and Protection Strategy groups, Kansas Grazing Land Coalition and Friends of the Kaw.