Farmers are Stewards of Ecosystems
What does it mean to be a successful, sustainable farmer? There are three elements to this: you must be able to maintain social harmony with the people in your family, operation, and community; to sell what you grow at a profit; and to maintain or enhance the planetary resources your operation relies on. People, profit, and planet. No one can guarantee sustainability for your operation, but in this lesson we will cover some very basic principles that can help you with this third element: being a good steward of your natural resources.
Whether you grow vegetables, fruits, flowers, fibers, building materials, or livestock, your business relies on using plants to capture sunlight. Plants turn sunlight into food for themselves, which can then be harvested by you or by your livestock and eventually sold for profit. The more effectively and efficiently you capture sunlight via plants and animals, the more raw materials you will have to convert to money in your pocket.
Thinking this way has helped some farmers save their businesses:
Bill Burrows, a former cattle rancher in CA, nearly lost his family farm in the 1980s as the beef prices plummeted. When he shifted his perspective to think of himself as a sunlight-harvester instead of a cattle farmer, he opened the door to creative thinking about ways to stay on the land. With help from family and friends he assessed all the natural assets of his farm and realized he wasn’t taking full advantage of them. Now the Burrows Ranch still raises some cattle, but thrives on income from no less than 7 enterprises, including offering nature retreats and hunting trips to urban visitors.
So how do you optimize your sunlight-harvesting ability? With a little creative thinking and by paying attention to the ecological processes described below.
B. Ecosystem health can be assessed through four windows: water and nutrient cycles, energy flow, and biodiversity.
“A nation that destroys its soils, destroys itself.” — U.S. President Franklin D. Roosevelt, 1937
When you manage a farm–no matter what type of farming you do–what exactly is it that you manage? Stand outside on a patch of ground and look around you. Every plant you see, from grass to tree, grows about as much mass below ground as it does above ground! Look down at the soil. In a single gram of it (which weighs about as much as a paperclip), there are over 50 billion microbes! (http://www.ces.ncsu.edu/depts/hort/consumer/quickref/soil/soillife.html) Many of these have not yet been identified by scientists.
All of this can feel overwhelming to a novice farmer. How do you know if your land is improving or deteriorating? How do you know if you’re polluting nearby waterways? You don’t need to be an expert scientist to gain some basic insights into how your management choices are affecting land, water, and wildlife health. You just need good observation skills. The best farmers are keen observers of what’s happening on their land. Think of the ecosystem you manage as a room with four windows. You can look through any of those windows to see what’s inside. These four “windows,” listed below, represent indicators of ecosystem health. These indicators overlap, and you cannot impact one of them without impacting all the others:
1. The Water Cycle – is the continuous flow of water between the atmosphere, the ground, and bodies of water. Just imagine – there is NO NEW WATER! Every molecule of water on this planet has cycled continuously through the bodies of plants and animals, through the atmosphere, and back down to earth thousands of times over. Water is a primary requirement for plants and animals to thrive, so the more we optimize our ability to hold water in the soil and in the landscape, the more we have available for production, even in dry periods.
What happens when a raindrop hits bare soil? Watch this mini-movie to see!
As you saw in the slideshow, bare soil makes it more difficult for rain to penetrate, to reach plant roots and to recharge groundwater supplies. The land in the slideshow is from an arid climate. Here in the Northeast, you would need to work harder to create that much bare ground! Still, if you stand in a crop field, or even in a patch of your lawn and look down, you might just be amazed at how much soil is visible between plants. A field that looks lush from the road may look quite different when you get out and look straight down at the soil.
Bare soil quickly degrades. When a raindrop hits it, it destroys the soil’s structure and makes it more difficult for future plants to get established. When many raindrops hit it, soil gets washed away, leading to erosion. Soil is built slowly, but can be lost almost instantly. And where does all that eroded soil go? It settles into streams, rivers, and lakes, wreaking havoc on water quality for wildlife, fishermen, and drinking water supplies. Eroded soil can inject large volumes of nutrients like phosphorus or nitrogen into the water, causing algal blooms, sucking oxygen from the water and decreasing visibility for creatures living in the water. This can affect food chains, habitat, and ultimately the structure of the whole water ecosystem! Not to mention that all those valuable microorganisms and nutrients contained in the soil are now a liability instead of an asset to the farmland from which they came.
Soil that is covered – by plant debris or living plants – is much less likely to wash away. And soil that is high in organic matter, meaning decayed plant residue, feels “spongy” and can retain water through long periods without rain. Let’s take a deeper look at this idea of covered soil through the next window, the mineral/nutrient cycle.
2. The Mineral/Nutrient Cycle – Imagine you’re in a forest. It’s autumn and the leaves are dropping around you. These leaves contain nutrients that the tree pulled from the soil with its roots. Over the next 6 months, the persistence of bugs, bacteria, fungi, and the mechanical forces of rain and snow will break down these leaves to feed their nutrients back to the soil. This constant cycling of minerals and nutrients from soil to plant material, through bodies of animals and back to the soil is what we call the Mineral or Nutrient Cycle.
Which minerals and nutrients are we talking about? These details are important for you to know for the specific crop you’re producing and are discussed in more detail in Unit 2: Evaluating Environment, Land Use, and Facilities. In this lesson, we are concerned only with the broad perspective of overall nutrient flow on farms.
Think about the entire farm as a big system, where nutrients are cycling from soil to plants and back into the soil. We can identify nutrient bottlenecks as well as major leaks. Of course, everyone who sells products raised on their land will have leaks, as those products sold represent accumulations of nutrients that came from the land. But the point is to try and minimize unnecessary leaks and to keep the minerals cycling quickly.
You will know if you are cycling nutrients well by looking, again, at the soil surface. Is dead plant matter (litter) breaking down? Do the plants that are growing look healthy, or do they appear yellowed, stunted, or otherwise nutrient-limited? If you have livestock, is their manure broken down and incorporated into the soil within a few days, or does it sit there untouched for weeks?
3. Energy Flow - We began this lesson with the concept that “Farming is a sunlight-harvesting business.” There is a one-way flow of energy: from sun to plants, and then to animals and humans, with energy lost or used along the way. We can envision this flow as a pyramid, with green plants at the bottom fed by the sun’s energy, and farm products for sale at the smaller top of the pyramid. If the money you make by selling items at the top of this pyramid is based on how much sunlight you capture at the bottom of this pyramid, what are the ways you can maximize this?
Three factors control how much solar energy you capture on your farm: leaf area, growing season, and volume of plants. In the humid Northeast, the latter two are most critical.
Many farmers utilize technologies – like row cover, black plastic, high tunnels (unheated plastic-covered structures), or greenhouses (heated glass or plastic structures) – to produce high-value crops that extend the growing season. Pasture-based farms might plant both cool-season and warm-season grasses, or even late-season brassica crops (the crop family that includes broccoli, kale, and cabbage), to extend the amount of time they can harness solar energy for forage. When animals harvest their own feed, it saves you the energy and cost of having to do it for them, which can increase the amount of money in your pocket!
Energy flow can also be maximized on your farm by intensive intercropping – planting multiple types of crops together (for example: growing a short-season crop like lettuce in the spaces between young transplants of a longer-season crop). Or in a livestock operation by grazing multiple species to take advantage of more of your forage production.
These practices also support the final indicator of ecosystem health:
4. Biodiversity – Left to its own devices, nature constructs elaborate ecosystems with many hundreds more interacting species than we humans tend to place in our agricultural systems. Why? What’s the point of diversity?
When we squeeze complex ecosystems down to just one or two species, we are removing the ability of that ecosystem to be resilient. If a pest or disease comes, that single crop is vulnerable. A famous historical example of this is the Irish Potato Famine in the mid-1800′s when 2/3 of the potato crop, a staple food for the country, was wiped out by blight. Diversity in your fields brings ecological stability, enabling you to manage whatever challenges the season brings. This ecological stability in turn generally means much greater stability for your bottom line too: if production fails for one of your crops, you have many others on which to rely.
To recap: the four windows, or indicators, into ecosystem health are the water cycle, mineral/nutrient cycle, energy flow, and biodiversity. All of these intersect at the soil surface. If your soil surface is bare, you will have poor functioning of all four indicators, and poor ecosystem health. Consequently, an overriding principle of good environmental stewardship is to minimize or eliminate any management practices that cause bare ground.