Making Crop Rotation The Standard
November 23, 2016 10:34 PM   Subscribe

Crop rotation sounds like such a great lo-tech tool for food production with a plethora of environmental good tacked on. So why isn't the usage of this tool commonplace? If it's economics, could we as consumers shift the incentives?

I imagine it is simple economics - monocrop + cheap synthetic fertilizers is more efficient than crop A + rotation crop B. If this is the case, are there any market-based solutions to tip the scales for crop rotation?

What if we eat more peanuts? But seriously, could we make a large enough market for legumes, clover, alfalfa or any nitrogen-fixing crop product and by-product, as consumers, to give crop rotation enough of a boost to be the easy economic decision for farmers?
posted by shaqlvaney to Science & Nature (10 answers total) 3 users marked this as a favorite
Can you tell us a bit more about where you are and what crops are local? I think most American corn-belt farmers grow soybeans. I live in the corn belt, and most farmers around here rotate corn, corn, soybeans (soybeans being a legume). It'd be better if they rotated corn, soybeans, fallow, but corn, corn, soy is okay. (Corn, corn, corn, with nitrogen fertilizer inputs is "traditional" since 1960ish, but most farmers have realized that a soybean year is cheaper and healthier.)

Soybeans are far and away the most profitable nitrogen-fixing crop. Feed clover is also good, as is alfalfa, but soybeans are the clear winner.

If you're a homeowner with a lawn, you can grow clover in it without disrupting the lawn look, and it will even make your grass look better because it'll shade the grass roots when they're dry and feed them nitrogen.
posted by Eyebrows McGee at 11:38 PM on November 23, 2016 [9 favorites]

I've lived in the Midwest, the Rocky Mountain West, and the Pacific Northwest, and everywhere I've lived, I've seen farmers rotating crops. The rotations are different in different places, because the soil, climate, and water availability allow for different crops. You can't just grow anything anywhere.

In the upper Midwest, like in Minnesota, they grow corn and soybeans because those are the two crops that you can reliably grow there. In the High Plains, I've heard a common rotation is wheat, sorghum, fallow, or wheat, fallow. In Eastern Oregon, a common 5-crop rotation is wheat, potatoes, onions, sugar beets, and sweet corn or dry beans.

There is a long-running drought in much of the West right now (some people are saying it's not a drought, just the new normal), and that's affecting crop rotations in many places, but even then you can see farmers trying to keep some kind of crop rotation, like in this article about Eastern Oregon.
posted by colfax at 2:56 AM on November 24, 2016 [4 favorites]

In my semi-rural location (Southern Wisconsin) farmers routinely rotate three crops: corn followed by soy beans followed by wheat.

This well-tested Wisconsin sequence provides N for corn as well as weed suppression and natural control of disease and insect pests. It was more profitable in recent years as the cost of synthetic N increased. Corn benefits from legume-fixed N, and from the improved cation exchange capacity in the soil that comes with increasing organic matter levels. Managing Cover Crops Profitably, 3rd Edition
posted by Short Attention Sp at 5:16 AM on November 24, 2016 [4 favorites]

So why isn't the usage of this tool commonplace?

What makes you think that it's not? My father is from a long line of farmers and rotation and fallow fields are absolutely standard to them and their neighbors.
posted by Candleman at 6:06 AM on November 24, 2016 [8 favorites]

So why isn't the usage of this tool commonplace?

Farmers will do what brings them in the most yield/money. One reason to not rotate crops is because you not only have the outlet for a specific crop, but also the equipment. If you don't see crop rotation, you may still see the use of cover crops between harvests to renew the soil.
posted by Toddles at 6:31 AM on November 24, 2016 [2 favorites]

I'm gonna assume your asking why U. S. farmers can't cut down on petroleum inputs. In 2000 a typical Missouri soybean acre yielded about 40 bushels twice what it was in the 1800s or even the 800s

From 2010:
"STARK CITY, Mo., – The 100 Bushel Club today announced Kip Cullers, Purdy, Mo., has established a new world soybean production record of 160.6 bushels per acre. The new world record is 6 bushels higher than the record Cullers set in 2007. In 2006, Cullers set a world record soybean yield record by producing 139 bushels per acre.

Cullers set the new world record by planting Pioneer® soybean variety 94Y71 on an irrigated and conventionally tilled field. He utilized BASF Headline® fungicide and DuPont™ Asana® XL and Steward® EC insecticides on his soybeans during the growing season as instructed on the product labels. His seed treatment included EMD Crop Biosciences® Optimize 400 and StollerUSA® Bio-Forge." He probably pretreated his fields with Roundup.

This year a farmer in Georga busted 170 bushels per acre. After Nixon's SecAg Earl Butts pronounced "Get big or get out." crop loans for small farmers dried up and the industry focused on economy of scale. Now, if you want crop insurance and loans, or to refinance those three $250,000 combines and the semi-tractor trailer rigs you need for 2 or 3 weeks a year at harvest, you better be doing the chemical-industrial agribusiness the bankers are used to.

The biggest organic polycrop farm I know of is White Oak Pastures in Georgia, its barely out of the small range at 3000 acres.
Here's a podcast that mentions the costs and risks he took to convert from a conventional beef operation.
posted by ridgerunner at 7:12 AM on November 24, 2016 [1 favorite]

Coincidentally, I just heard a bit about this very issue on Chef's Table (on Netflix). Dan Barber (chef focusing on farm to table cuisine) was talking with a farmer about crop rotation and yes, you nailed it: we need to create a demand for the crops that are generally grown at a loss (rye was one, I believe) that nonetheless increase the yield for the profitable crops. If you're interested in more, it's the second episode of the series.
posted by the thorn bushes have roses at 11:46 AM on November 24, 2016

Crop rotation is driven primarily by profit margin and industry lobbying; crop and soil health usually takes second place. I don't know a ton about American ag, so someone please correct me if I'm wrong, but my understanding is that the farm subsidy regime in the US drives a lot of crop choice. (As in, soy and corn are so heavily subsidized that it doesn't make sense to rotate beyond that in some areas.) And farm subsidy regime is influenced by powerful industry lobby groups. Short rotations benefit ag input suppliers immensely because short rotations are more susceptible to disease and require more intensive managing (more applications of herbicide, fungicide, expensive trait-stacked seed, etc.)

It becomes a vicious cycle. As farmers, we'd love to be on a 7 year rotation -- say, barley, 2 years of green feed, then wheat, flax, oats, peas. And there are brave souls out there who do it. But years 2 and 3, you're not really pulling in any income unless you happen to farm in some magical area where there's huge demand for greenfeed. So in order to be able to pay the bills every year, you end up growing annual crops, and pushing the rotations.

The best way for you as a consumer to shift big-ag policies? Become a trillionaire and use your money to out-lobby the industry groups. Barring that, buy local. Talk to farmers you meet and ask them about their rotations, and WHY they do them. Be prepared to look harder and pay more for local food grown sustainably. Encourage those in your community who can afford it to do the same. Quit buying processed crap made from soy and corn derivatives. Be a loud and persistent voice with your political representatives. Small farms often don't have the same access to the subsidy regime that large farms do.
posted by bluebelle at 7:08 PM on November 24, 2016 [1 favorite]

The equipment for both planting and harvesting are different, even for just corn and soybeans. Potatoes, spinach, onions, etc, require whole infrastructures off the field also (look up potato truck, spinach pack house, onion line). If you were to rotate you would have a huge amount of capital depreciating every year without producing any earnings.
posted by 445supermag at 8:31 AM on November 25, 2016 [1 favorite]

It's not quite that dire for even medium size operations as it's not like you'd plant all your quarters in the same crop in any particular year. Instead you'd have 1/7 (or whatever) of each of your fields in each of the crops. You'd only need enough of that specialized machinery to plant/harvest/etc. 1/7th of your fields.

And splitting things up like that provides a bit of a hedge on conditions that may favour one crop over the other and can help with scheduling of resources if the harvests/planting spreads out. It doesn't really solve the problem of one crop being unprofitable instead spreading the pain which could make it easier to absorb especially if long term it reduces your inputs.
posted by Mitheral at 2:56 PM on November 25, 2016

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