This Closed-Cycle Method Could Dramatically Lower Dairy Farms' Energy Use

There’s been a trend in the past few decades of rediscovering closed, or fairly closed, cycles of farming. What that means is using one crop to feed another. An example, one used by a new study from Penn State University: Instead of merely raising dairy cows and importing all the feed for them, you can raise the cows, use their manure to fertilize crops, and feed those crops to the cows. It’s a clean, simple, and very ancient technique, as New York chef Dan Barber famously described in a popular TED Talk.

The Northeast, especially Pennsylvania, New York, Vermont, and Connecticut, are huge dairy producers, but not so big on the crops that are used to feed the cows, like corn and soy. It’s not that those crops can’t grow in the Northeast, but rather that Midwestern states produce it much more cheaply and transportation is cheap.

But that’s not a great use of energy; for one thing, it involves a lot of trucking and shipping, which is pretty lousy energy-wise, but the separation also makes it unnecessarily difficult. The cow manure stays in the Northeast, for the most part, so Midwestern farmers usually use synthetic nitrogen-based fertilizers, which are incredibly energy-intensive to produce.

This new study set up three different scenarios in which Pennsylvania dairy farmers crow their own crops, both feed crops like corn and soy and forage crops like alfalfa and rye. One of those scenarios even went a step further, having the dairy farms grow canola, which is processed on-site into fuel for the tractors to harvest the crops.

The farms that produced their own feed used a whopping 15 percent less fossil fuel.

The easiest of all the scenarios had the Pennsylvania farmers simply grow foraging crops, which is cheap to plant and grows happily in the Keystone State, and import all its feed grain. Even this very minor change has a positive impact on energy use, but when compared to the other setups, we can really see how big an effect growing your own feed can have. To produce the same amount of milk, the farms that produced their own feed used a whopping 15 percent less fossil fuel than the easy farm.

There’s no mention of price in this study, which leads us to believe that this isn’t necessarily cost-effective out of the gate. Tilling and starting feed acres from scratch isn’t cheap. But this is exactly the kind of research that can provoke government grants: If, say, the USDA covered that initial cost, this could be worth it for many farmers.

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