4 minute read
Lessons From Leopold
A Fountain of Energy
BY STEVE NELLE
Photo Courtesy of the Aldo Leopold Foundation and University of Wisconsin-Madison Archives.
When we think of energy, we usually think of hydrocarbons such as oil, natural gas and coal, or the electricity that is generated from these fossil fuels. Some may think of wind farms or solar energy. We think of the pipelines and powerlines that crisscross Texas to transport energy from where it is produced to where it is used.
But we usually do not think about the land itself as a component in the flow of energy—even though this is the primary means of energy production and transfer on the planet. Every young student learns that sunlight energy striking green leaves is transformed into a different kind of energy by the process of photosynthesis. Plant energy in the form of carbohydrates is what feeds man and beast and what sustains all life on earth.
Physicists calculate that on average, about 100 watts of sunlight energy per square foot is continually received during daylight hours. On one acre this is enough raw energy to power nearly 600 homes or the equivalent of 464 gallons of gasoline each day. It is interesting to consider that fossil fuels are also the result of this massive transfer of sunlight energy to plant energy that took place eons ago and is now stored in the ground for our use.
Our management of the land determines in large part to what degree sunlight energy is put to good beneficial use. Energy conservation on the farm or ranch is a lot more than being careful with fuel and electrical consumption. Energy efficiency can be viewed as managing every square foot to maximize the conversion of the sun’s energy though beneficial plants.
The biggest wastage of energy is when sunlight strikes bare ground. In the summer, bare soil absorbs solar energy and heats up to 130 or 140 degrees—hot enough to kill or suppress the growth of soil microbes. This in turn hinders soil health, infiltration and water holding capacity. We may cook our steaks to 140 but we should not be cooking the soil. An over-heated soil, just like an over-heated motor impairs its productivity and is a sign that things are out of kilter.
In the grand circuit, the energy in plants is transferred to the animals that consume plants—livestock, deer, rodents and insects. In some cases, the food chain is simple as in the case of cattle eating grass and other cases it is more complex with several links.
At each step in the food chain and at the end, there is decomposition whereby waste products or the dead plant or animal is broken down and the energy (carbon) is cycled back to the soil and the atmosphere to fuel next generation plant growth. It is difficult to comprehend how perfectly the system works.
On ranches, there are several ways to ensure the efficient conversion of sunlight energy to plant and animal energy. There needs to be green plants growing all throughout the year, even in the winter. Cool season plants and evergreens should be mixed with warm season species.
A healthy energy cycle also requires a diversity of plants which enables the most effective capture and conversion of sunlight. Deep rooted plants including many brush species are able to remain photosynthetically active even in drought. Short lived annuals can provide quick green cover while the slower growing perennials get established. Every different type of plant has its own niche in the energy circuit.
Animal diversity is also needed for the efficient transfer of energy. Soil organisms, insects, rodents, small mammals, larger herbivores, birds, predators, decomposers are all needed to keep the circuit humming. A gap at any stage interrupts or weakens the flow of energy through the system.
Landowners tweak the controls of the terrestrial energy cycle with grazing, fire, brush control, timber harvest, farming practice and hunting. By increasing or decreasing the pressure of these adjustments man becomes a key part of the energy circuit. We marvel at the natural balance that has been created; and we humbly acknowledge the responsibility we are given to care for and manage it for beneficial purposes.
WRITER’S NOTE: Aldo Leopold (1887—1948) is considered the father of modern wildlife management. More importantly, he developed and described many of the concepts of conservation, ecology and stewardship of natural resources. Leopold was an amazingly astute observer of the land and man’s relationship to the land. His writings have endured the test of time and have proven to be remarkably prophetic and relevant to today’s issues. This bimonthly column will feature thought-provoking philosophies of Aldo Leopold, as well as commentary.
