The Many Benefits of Multi-Year Crop Rotations


Relevance to Farmland LP

At Farmland LP we describe what we do as converting conventional farmland to Organic, sustainably-managed farmland.  While getting the land certified Organic is helpful for marketing, the broader benefits are in our land-use rotation practices.  Since our full cycle crop rotation can easily span 10 years—five to seven years in pasture or perennial forage crops followed by three to five years in vegetables and grains—it makes it a challenge to scientifically benchmark our soil-biology-driven practices vs. current chemistry-driven practices. The irony is that our rotation style was the norm for centuries.  Farmers rotated by necessity for thousands of years to maintain soil fertility and lower disease risk.  Agronomy advanced by increasing the number of crops in a rotation, such as the innovation in the 16th century of adding legumes to European crop rotations.  In the mid-20th century U.S. farms averaged five commodities per farm, including crops and livestock.  Only in the past 60 years have farmers had the tools (i.e., synthetic fertilizers and pesticides to deal with the problems of reduced diversity) not to rotate, and now farms are highly specialized with low diversity of about 1.2 commodities per farm (see graph below).  Some see this as modern progress, but at Farmland LP we view this multi-decade chemical binge as an abandonment of centuries of wisdom that is causing both ecological and economic damage.

From defenders of the status quo I can hear the following argument:  “Yields of today are so high that adopting historic practices will put farms out of business and not feed the world.”  To those who understand the research study, this argument is silly.  Current yields are not a result of simplification and won’t be undone by diversification.  We can still use modern crop breeds and modern equipment while adopting soil practices that dramatically lower external inputs and avoid the externalization of costs, such as pollution.  A more diverse system will be a net benefit for the farmer while making the food production system more resilient and environmentally positive.  This has been the position of Farmland LP since our inception, and was a strong impetus for our business.  Our goal is to be a successful model of more diversified, sustainable farming practices that re-integrate crop and livestock production. A single chart from the paper (shown below) does an excellent job of telling the whole story.  It shows that key production metrics that farmers care about, including profits, yields and weed pressures, are the same or better than conventional in longer rotations, while the longer rotations prevent most pollution and lower the need for synthetic inputs such as fertilizers and pesticides.  Labor costs are higher in more complex rotations, which we view as providing opportunities for meaningful work. Profitability is the same due to reduced expenses for synthetic fertilizers, herbicides and fuel. That’s a good trade that will get better as inputs costs keep increasing.

 One of my favorite paragraphs from the paper is:

How Farmland LP’s Rotations Improve On The Research

While the research design and conclusions here are very relevant to what we do at Farmland LP, there are some differences.  Here are a few points of how our systems further improve upon the system presented in the research paper:
  • Certified Organic Price Premiums.  Some synthetic fertilizers and pesticides were used in all rotations, but they were just not needed much in the longer ones.  Taking it just a little bit further would have enabled them to get the Organic price premium in the 4th year and beyond. Even with the potentially higher costs of Organic versions of external inputs when available, the net returns would be higher in a Certified Organic system.
  • Livestock Grazing on Cropland.  The forage crops were mechanically harvested, not grazed.  Farmland LP puts a lot of our land in diverse pasture and  grazes livestock intensively, whereas the research system harvested alfalfa as hay which was then transported to livestock.  The manure of livestock was then brought back to the research plot for fertilizer.  So we differ by having even more plant diversity than the study (better for the soil) and by getting the benefits of direct grazing, such as further reductions in fuel use.
  • More Complex, Longer Rotations.  The study was made feasible by its relatively short rotations of 2, 3 and 4 years.  Our rotations are more complex and reflect more natural economic and biological rotations and durations.  For example, an alfalfa-orchard grass stand should last five years or longer, same as pasture.  Many crop options were not included in the study, such as vegetables.  With our program the environmental benefits should be even greater than shown in the study, including significant carbon sequestration.
We applaud the scientists who carried out the work and the USDA for lending support too.  We certainly hope it leads to more sophisticated discussions among stakeholders in the food system, whether policy-makers, farmers, and eaters of food.  And we thank those who’ve supported us at Farmland LP for your role in fostering much needed change.