Profitable Polycultures

Farmers can improve overall profit by using natural ecosystems

For more than two decades I have been a passionate perennial crops farmer. I was inspired by J. Russel Smith’s classic Tree Crops: A Permanent Agriculture way back in 1988. It changed my life and I have not turned back. It led to the New Forest Farm project in Viola, Wisconsin, and in my being an early member of the Organic Valley farmer’s cooperative. 

This long history with perennial crops, and the development of the organic industry out of nothing, has given me a particular perspective — one that I hope the reader will find helpful. 

Probably the most significant piece of encouragement I would like to offer prospective perennial crops growers is to not get sucked into the myths propagated by people who say that you can’t make any money growing Kernza, for example, because it doesn’t yield as much as annual wheat, or that “the right varieties” of hazelnut don’t yet exist in order for an operation to be profitable. 

These myths are based on the premise that growers will be growing “fields” of perennial crops or “orchards” of woody crops. However, I believe the age of the monocrop is over. It is not a viable long-term production model, and nature has the track record to prove it. 

We, as the practitioners of ecological agriculture, must learn to imitate natural ecosystems in our farming practices in order to remain profitable. Remember — natural ecosystems, with their assemblages of plants and animals, have been around since the dawn of time. Natural ecosystems have been solving the problem of living for as long as there has been life on earth, and it has been doing so at zero cost. 

Researchers — whether in a laboratory or in the field — simplify their studies so that they can “isolate” one or two variables in order to try to discern the precise mechanisms determining certain outcomes. Natural systems and natural processes are not simplified, controlled experiments, however. They are actually the world’s most advanced supercomputer. The AI (actual intelligence) of the natural world is operating non-stop under the actual, non-controlled conditions of planet Earth and is solving for hundreds, if not thousands, of constantly changing variables every second of the day and night. This is how life has persisted for as long as it has. 

Nature doesn’t grow orchards. Very few plant species exist in pure stands of more than several dozen acres. Natural ecosystems are predominantly polycultures — i.e., many different species growing in the same place. Natural plant communities (along with their animal associates) exist right along with pests and diseases. Soil fertility is created and maintained by the ecosystem itself. Although some of the crops (vegetation, fruits, nuts, seeds, animals) are “cosmetically flawed,” many are perfect, and they are perfect despite the fact that zero external inputs were applied and no money was spent in their production. Cosmetically inferior products are recycled by the system and are eaten by animals or are decomposed (re-composed?) by fungi — once again at zero cost. 

Natural plant and animal communities provide the ecological model for economically productive perennial agriculture. In an orchard, the grower is responsible for weed control, pest control, disease control and the removal of pest- and disease-infected fruit or foliage. This represents work — it requires expensive equipment and purchased inputs. This is all totally unnecessary. 

“But you won’t get the yields that way!” is a common cry from those who don’t want to believe in nature’s success. This is both true and not true and leads me to the illustration of a principle that is becoming more widely understood. 

In my book Restoration Agriculture I discuss the principles of “overyielding polycultures.” Ecological research has shown over and over again that the total yield of a site is greater in polycultures than in monocultures. In agroforesty, the term “land-equivalent ratio” is used to describe this principle. 

If you grow a monocrop of corn, you will get a maximum yield of that corn — you’ll get 100 percent of a crop possible for the site conditions of that year. 

If you grow a monocrop of apples, you’ll get a maximum yield of apples: 100 percent of the apples that can be produced in that calendar year. 

If, however, you plant a simple polyculture using both apples and corn on the same acre, everything changes. The naysayers are right! You will not get the yields you would have if you had grown the crops by themselves! If you planted apples and corn in an alley cropping system that included 80 percent of the corn and 50 percent of the apples, you would get less corn and fewer apples. Your individual yields go down. However, your overall site yield would be greater than either corn or apples alone. Eighty percent of a corn crop plus 50 percent of an apple crop equals 130 percent total site yield, for a land-equivalent ratio of 1.3. 

How would this apply to us as perennial farmers? I don’t have to get 40 bushels per acre of Kernza in order to be profitable (40 bushels is average U.S. wheat yield). Kernza isn’t my only crop. I don’t have to get 2,800 pounds of hazelnuts per acre in order to be profitable (the average yields in Oregon when plants are mature). Hazelnuts aren’t my only crop, and I don’t have to spend $600 per acre for weed control in my chestnut polyculture because cattle are eating the grass and weeds and creating 300 pounds of beef per acre. I don’t have to spend money on fertilizer because the cattle are urinating and defecating around my trees. I don’t have to haul away pest- and disease-infected fruit and nuts because pigs do it for me, creating yet another revenue stream. Kernza or hazelnuts become a profitable component of a polyculture. 

Again, the naysayers are right — I do get lower yields of everything in the system. Less corn, less wheat, fewer apples, fewer hazelnuts, etc. The total site yield, however, is more — with drastically reduced expenses. Instead of having chestnut trees pulled out of their ecological context, I have them living in an “almost natural” ecosystem. There is now habitat for pollinators — not in a set-aside “pollinator habitat program” paid for with tax dollars, but as part of the production system itself. Tree frogs and toads eat insects, weasels eat mice, and biodiversity improvements are a side-effect of production. 

So … perennial farmers: plant polycultures! Get higher total site yields by getting lower individual crop yields. Reduce your input costs to nearly zero. Imitate the plant community types that thrive in your region and you’ll find that your system will thrive just like they do. 

Let’s all observe nature and learn from it directly. Let’s plant perennial cropping ecosystems and create a healthier, more ecologically sound future for ourselves and our children. 

Mark Shepard is the founder of New Forest Farm in Wisconsin and Forest Agriculture Enterprises. He is the author of Restoration Agriculture and Water for Any Farm.