Animal impact is another tool in the model. The grazing tool simply looks at the relation between the animal and the plant through the eating process. The animal impact tool, on the other hand, looks at the relation between the animal’s behavior and its impact on the land.
When discussing animal impact, it helps to think about how a wild herd of animals behaved before modern human practices changed the natural processes significantly. Take a herd of bison roaming the Plains a couple of hundred years ago. Herds — some estimate that individual herds once numbered hundreds of thousands of animals — came through an area and ate everything in site. Because of predators, including Native Americans, these large herds of herbivores ran in tight formations: It’s harder for a predator to pick off a prey animal from a tightly bunched group. When a herd came through the animals not only ate all the available forage, but also trampled the soil surface and deposited massive quantities of manure and urine. When the herd moved on, the area looked decimated, but the animal impact stimulated new growth. The herd would not return for a long period, allowing the plants adequate time for a full recovery. When they did return, the process began again.
Figure 3.4. Stocking rate is a measure of the total acres available per animal; stock density measures the animals (as 1,000-pound or 454-kg animal units [AU]) in an individual paddock at any one point in time. A farm with 80 acres (32 ha) and 40 AU would have a stocking rate of 2 acres (0.8 ha)/AU. If those animals were concentrated on a 10-acre (4-ha) paddock, the stock density would be 4 AU per acre (10 AU per ha).
Animal impact is the result of stock density and herd effect. Stock density differs subtly from stocking rate. The stock density is not measured in animal units (AU) per acre, but on incremental acres in a paddock for a short period of time. The stocking rate refers to the total acres per AU on the farm. One animal unit is approximately 1,000 pounds (453.6 kg) of live animal (Table 3.1). Figure 3.4 shows examples of stock-density and stocking-rate calculations.
Herd effect is achieved by animals moving excitedly. In the example above, the herded bison were bunched tightly, and when predators were near they moved in an excited and animated fashion. Picture a stampede, and you picture a high-level herd effect. When humans significantly reduce predator impact, both wild and domestic, animals tend to graze placidly, and that placid behavior results in low herd effect. Luckily, playful and happy animals, not just scared animals, can create high herd effect.
Living Organism
The living organism tool seeks to use biological systems to move toward goals. The great horned owl eating our pigeons is a good example of the tool of living organisms, even if we didn’t realize we were employing the tool until the job was almost done.
By fostering a complex environment with lots of biodiversity, we encourage living organisms to do a good bit of work for us. At times, however, we may go out of our way to use one particular living organism. Introducing a beneficial organism to control a pest (say, ladybugs to control aphids) and enhancing the environment for a beneficial organism (placing bat houses around to reduce mosquitoes and other insects) are good examples. Planting windbreaks is another good example of using living organisms as a tool.
Technology
The last tool at our disposal is that two-edged sword, technology. Technology is nothing new; the first tool made from a piece of rock was a form of technology. Now our technology has reached almost unimaginable and at times, dangerous levels.
Those of us interested in sustainable agriculture are often accused of trying to turn back the clock and do away with technology. This isn’t quite true, but we don’t want technology to be the only answer humankind can come up with, either, because often enough, it isn’t the best answer to a problem.
Sadly, our current reliance on and fascination with technology have evolved out of a “science is absolute and perfect” paradigm. Yet no matter how small a particle physicists can define and study, they still haven’t explained the “nature” of nature; in other words, they haven’t looked at the whole. In 1932, the physicist Max Planck eloquently summed up this idea when he said, “Science cannot solve the ultimate mystery of nature, because, in the last analysis, we ourselves are part of nature, and therefore part of the mystery to be solved.” Interestingly, scientists in many fields are beginning to come to terms with this, through their work on chaos theory. These scientists are trying to put the pieces back together as a whole.
Table 3.1
ANIMAL UNITS
Technology is a tool that has a place on your farm and in your planning. For example, recent improvements in fencing technology make it possible for you to manage livestock so that you balance the animals’ needs and the plants’ needs, while emulating herd effect, with minimal labor. When you use the model, technology, like any other tool, is evaluated for its appropriateness to your goals, and used accordingly.
In a grass-based livestock system, few technological tools are really necessary. So many farmers tie themselves to payments on “heavy metal” such as tractors, plows, disks, planters, and harvesting equipment. These things cost a great deal of money to purchase, they depreciate while you own them, and they require significant amounts of time for maintenance.
When we first purchased our Minnesota farm, we went out and bought an extensive line of equipment. We could have done without most of it; we would have made more money if we’d put the funds that we tied up in equipment into some type of financial investment instead. It pays to rent equipment when you need it, or else to use the services of contractors to do a good deal of your work. This time around, our only equipment is our four-wheel-drive truck and a stock trailer.
Grass-based agriculture also allows you to avoid, or minimize, the use of chemicals on your farm. In Minnesota, the only chemical we ever applied to the land was lime. We rarely used antibiotics, wormers, or other chemicals directly on the livestock. We were able to use natural products such as homeopathic medicines and diatomaceous earth instead. (See chapter 8, Health & Reproduction.)
The Guidelines
The guidelines are the final part of the holistic model and are used for testing and managing ideas during planning and implementation. As Allan Savory says in Holistic Resource Management (Island Press, 1988):
On first exposure, the guidelines appear a bit confusing. Some titles seem absurdly abstract and others narrowly concrete. . . . Unlike the broad principles discussed earlier, they were not born out of systematic theoretical analysis, but from the day-to-day demands of connecting neat theories to the messy realities of practical life.
The testing guidelines — sustainability, weak link, cause and effect, marginal reaction, gross profit analysis, energy/money source and use, and society and culture — allow you to evaluate ideas, enterprises, and tools during the planning stage. Your goal is to choose the ideas and enterprises that most effectively move you toward your broad goal.
Once you’ve decided on an idea, enterprise, or tool, the management guidelines help you implement and monitor the project. The management guidelines include: time, stock density, herd effect, population management, burning, cropping, marketing, organization and leadership, financial planning, land planning, and grazing planning. In my simplified planning process, I don’t apply the management guidelines directly — though they are incorporated into the process.
I’ll discuss the testing guidelines in more detail in chapter 12. For now, just remember that each guideline is intended to move you toward your holistic goal.
CHAPTER 4
Grass-Farming Basics
The grazed meadow, or pasture, or grassland — call it what you will — is the ecological and economic foundation of farming.
— Gene Logsdon, The Contrary Farmer
WE THINK OF OURSELVES as “grass farmers.” We collect solar energy in the grass and then convert it to a product in the form of livestock. One of the best things about grass farming is the way it puts you in touch with your piece of land and your animals — both domestic and
wild. Except for the thick of winter, you spend some time walking your land almost every day. We came to differentiate a hundred shades of green during the seasons: the first light bright greens of spring, the brilliant dark greens of summer, and the pale golden greens of fall. One spring afternoon, we lay down in the grass and watched the sun fade away, a great red ball sinking into the pink horizon. The hazy light of late afternoon revealed an infinite universe of ground-spider webs waving on the breeze at the interface of grass and sky. All the grass farmers we know speak in tones of reverence about the experiences they’ve enjoyed on their land and with their animals.
Since the basis of all animal agriculture is forage, and grass is the most abundant forage on the planet, grass farmers are remaking natural connections. The industrialization of animal agriculture has eroded the importance of grass and replaced it with grain and processed feeds, but for the small-scale farmer grass needs to again become the centerpiece of the farm. Like their wild cousins, domestic livestock can live off grass with little or no supplemental grain, though some classes may require browsable plants (forbs, woody shrubs, and trees) as well.
Grass, for our purposes, is any plant grown for its forage production, including both the true grasses and the legumes. The ideal forage for grazing is a mixture of true grasses and legumes, not a monoculture of any one plant; however, a monoculture may be planted for special purposes, such as establishing a new field or providing winter feed.
Many “weeds” are actually great forage plants. Crop farmers despise quack grass, but early settlers called it miracle grass because it produced good pastures, and animals savored it. Dandelions are always an early-season favorite for our cows and sheep.
Remember that all energy comes from the sun. It’s the conversion of solar energy to chemical energy through photosynthesis that makes animal life possible. Grass farmers recognize this conversion, and work to maximize it.
Grass Reproduction
Grass plants are spermatocytes, or seed-bearing plants. Each begins life as a seed, and their ultimate purpose is to produce new seeds. True grasses (such as timothy, brome, bluestem, fescue, and even corn) grow from one initial leaf, whereas the legumes (clover, alfalfa, bird’s-foot trefoil, peas, and beans) grow from two initial leaves. The plants that start from a single leaf are called monocotyledons, or monocots for short; those starting from two leaves are called dicotyledons, or dicots. The monocots tend to have a more fibrous root system, and the leaves have parallel veins running through them. The dicots have thicker taproots that look like a carrot, and the leaves have patterned veins, like a web or net (Figure 4.1).
Some plants are annuals, and must reproduce each year from seeds. Others are perennial plants, which live from year to year. Of the annual plants, some are self-seeding, so for practical purposes they behave like perennial plants.
Figure 4.1. Plants that sprout with a single leaf are monocots; those that sprout with two leaves are dicots. Most grasses are monocots, and most legumes are dicots. The monocots tend to have a shallower and more fibrous root mass, whereas the dicots have a deeper, tap-rooted mass.
Some plants reproduce only from seeds (sexual), but for other plants new growth may also come from existing roots (asexual). Sexual reproduction produces unique genetics in each plant, but asexual production results in genetically identical plants. For example, a grove of aspen or poplar trees is often genetically one plant; each tree simply sprouts from the roots of an original tree. When you purchase annual hybrid seeds from a seed dealer, you are getting the same type of identical genetics that occurs in asexual reproduction. Identical genetics was a key condition for the 1995 outbreak of gray leaf spot in the corn crop: One hybrid was planted extensively throughout the country that summer, and it had low tolerance to the disease.
Feeding the Grass
Like animals, plants need to eat and drink. The primary nutrients they require to grow healthy and vigorous are nitrogen, phosphorus, potassium, calcium, and magnesium. A vast array of other trace nutrients is required as well: sulfur, copper, and iron, to name a few (Figure 4.2).
True grass plants get all of their nutrients directly from the soil, but legumes can acquire part of their nitrogen from air molecules captured in the soil. This ability to take nitrogen out of the air is called nitrogen fixation. The legumes are able to fix nitrogen due to a symbiotic (mutually beneficial) relationship they have with a group of bacteria known as rhizobium. These bacteria live in nodules on the roots of a legume plant, allowing the legume to capture nitrogen not regularly available to plants and convert it to a soilborne form that the plant can reuse as it is needed. The beauty of this process is that most legumes fix far more nitrogen than they need, yielding additional nitrogen in the soil for other plants to feed on. Fertilization with inorganic forms of nitrogen reduces the activity of these beneficial bacteria, thereby requiring even higher levels of fertilizer in the future.
Figure 4.2. Plants acquire most of their food and water through their roots, though some can be absorbed through their leaves (foliar feeding). Plants regularly absorb carbon dioxide through their leaves and discharge oxygen and water through their leaves.
All plants require water for growth, but some require more than others do. Plants that grow in very wet or waterlogged soils are called hydrophytic. These plants tend toward thick, waxy surfaces. The xerophytic group (plants that survive in dry soils) have narrow leaves and tend to be spiny or barbed: nature’s method of protecting them from overgrazing by herbivores. Mesophytic plants grow in well-drained and well-aerated soil with moderate moisture. These are favored as forage producers, but livestock can use some xerophytic and hydrophytic plants as well.
Most grasses like to grow in a well-buffered, or neutral pH soil; pH refers to a soil’s relative acidity or alkalinity, and is reported on a scale of 0 to 14, with 7 being neutral. Numbers below 7 represent acidic pHs; numbers above 7, alkaline pHs. The ideal pH for most plants is between 6.5 and 8.0. A quick test of soil pH can be made using litmus paper, which can be purchased at drugstores. Place a piece of litmus paper in a ball of barely moist soil for a minute, then pull it out and compare the resulting color to the chart on the back of the package. This test is especially worthwhile if you farm in a nonbrittle environment, where excessive moisture leaches alkalinity from the soil.
With a healthy polyculture of grasses and legumes, on soil where the four ecosystem foundation blocks are operating well, you’ll need little external fertilizer to feed your grasses. However, there will be times when a little extra fertilizer may help, particularly lime if your soil’s pH or calcium levels are low. Part IV, Planning, will help you decide when external fertilizers are the best place to put your money.
If you do decide to fertilize, several small applications throughout the growing season are far more beneficial than one big application, especially for nitrogen. Small applications don’t harm the soil’s microorganisms the way a big application does, and they are less likely to run off or leach from the soil, because plants take them up quickly or they become stable in the soil.
Managing Peak Growth
Because grazable forage is the primary source of feed in a pastoral system, learning to keep it growing well is critical. The ability to manage grass for peak growth is both an art and a science. It takes a keen appreciation and awareness of both the plants’ and the animals’ needs, which only comes with time and practice. Still, some general observations might just help.
Growth primarily takes place at each plant’s basal growth point, which is located near the soil surface (Figure 4.3). Seeds provide the nutrients required when plants first sprout, but rather quickly the roots must develop and begin supplying all the nutrients for continued growth. As the season progresses, the nutrients are used for the development of a flower and seed head. (Some perennial and biennial plants don’t try to make a seed head each year. Biennial plants are a special class of plants that need two years to do what an annual plant does in one.) As the seed head develo
ps, the root system becomes depleted of its energy supply, and the plant will be vulnerable to additional stress.
If plants are clipped — either by mechanical means or by an animal biting them — before they begin developing the seed head, the roots keep supplying energy for leaf growth instead of seed production. However, clipping too much or too often reduces the energy in the root system too much, thereby slowing leaf growth. Understanding these principles and learning to work with them will allow you to manipulate plant growth for maximum leaf (forage) growth. It also allows you to control weeds: Mechanically clip perennial weeds, such as thistles, just as the seed head begins to form, but before it opens. This is the moment when the plant’s energy reserves are at their lowest point of the growing season. If you clip before the seed head begins to form, the plant just keeps making more leaves, and still goes into seed production as soon as it has enough. If you wait and clip after the seed head has opened, it’s too late — root energy levels increase rapidly after seed dispersal. You may not kill the plant the first year you do this, but given a couple of years of timely clipping you will significantly reduce weed pressure.
So how much grazing or mechanical clipping do you want to do to maximize leaf production? It depends on the time of year, temperature, precipitation, soil fertility, and other mysterious forces (Figure 4.4). But don’t give up hope, because there are some rules of thumb that you can use initially, and with practice you’ll get to know how your grass is doing. As André Voison, an early pioneer of managed grazing, said in his book Grass Productivity (republished by Island Press, 1988), “In the long run, it is the eye of the grazier, supported by his experience, that is the judge.” Chapter 14, Biological Planning, will go into more detail on manipulating plant growth through grazing, but for now mull over the rules of thumb.
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