Climate Change, Raising Hogs, and Feeding the Elephants

Cover crops in my cover crops. The "grass" is rye emerging through clover and weeds in a idle field. I broadcast the rye in standing water on the field in mid September and got a beautiful stand so far.

On Friday, November 23rd, the federal government released its report on climate change. You can read the report here. The gist: If you think weather-related events are bad now, it’s only going to get worse –a lot worse.

I’m thinking about the farm and the land itself and the things I need to change. If the eleven inches of rain we got in August is a harbinger of future weather events, I wonder if I’ll still be able to keep raising hogs and the crops to feed them. I wonder if I can build enough resilience in the farm by feeding the “elephants”.

Back in August, I attended a great field day in Dodge County that included a presentation by Dr. Jerry Hatfield, Director of the USDA National Laboratory for Agriculture and The Environment.

Dr. Hatfield charted the deviations in our average rainfall and temperatures over the past century and specifically pointed to the increase heavy precipitation events (this was only a few weeks before the flooding around Dane County). “I'm not talking about [future] climate change,” he declared. "This is what's already happened."

Dr. Hatfield explained that the overwhelming majority of crop insurance claims come from either too little moisture–drought–or too much–flooding. He went on to explain that biologically active soil with a more diverse crop rotation (compared to corn and soybeans) and a diverse mix of cover crops both inter-seeded into cash crops and grown between cash crops (overwintering) will build soil more resilient to climate change’s effects.

Healthy soils have higher organic matter. An increase of 1% organic matter in soil translates to absorbing an additional inch of rain per acre (an acre-inch of rain is about 27,000 gallons). Increase the organic matter in soil and you get water infiltration instead of runoff that turns into flooding. That water-holding capacity–along with cover crops to shade the soil–also helps soil retain life-giving moisture in a drought.

But it’s not just about water.

“Soil needs to breathe,” Dr. Hatfield explained.  “The number one limit to crop production in Spring isn’t water, it’s oxygen.”  A 1/32” crust on soil will block the oxygen/carbon dioxide exchange between the soil organisms and air. Tillage followed by rain creates that crust on bare soils. Cover crops protect the soil, preventing that crust from forming.  Crusted-over or compacted soil “is like a person with COPD,” Dr Hatfield explained.  “It can’t breathe.”

Improving soil health will increase soils’ resilience to excess or limited rainfall–conditions we'll see a lot more in the future.

There are five principles to soil health, based on how nature builds soil:

1.  Keep soil covered at all times
2.  Minimize physical (tillage) and chemical disturbance.
3.  Maximize plant diversity.
4.  Maintain living roots.
5.  Integrate livestock.

I’ve been using cover crops since I started farming a few years ago, but I was doing simple covers like medium red clover and using tillage in the spring to work them in. Now, I try to keep something growing in every field: pasture mixes between harvested rows of corn; sorghum-sudangrass chopped as a mulch with sweet clover planted into it; triticale broadcast on lightly disked and untilled ground; and rye emerging through grass and clover pastures. Except for where the pigs made mudholes in some of the pasture divisions during our eleven inches of rain in August, I feel like I have a good start on following the soil health principles.

Scientists estimate that a teaspoon of healthy soil might have a billion microorganisms in it. I knew that my cover crops were helping feed that soil life, but I didn’t understand the scale until Dr. Hatfield put it in perspective.

“An acre of biologically active soil will have 10,000 lbs of living organisms in it–that’s two African elephants.” Those two “elephants” under a single acre each consume about 500 lbs of material a day. That's a lot of livestock to feed. Knowing that, I'm trying to build plenty of biomass in order to feed the underground "elephants" on the farm.

In addition to feeding the underground “elephants”, those cover crops are also sequestering carbon.

At the end of Dr. Hatfield’s presentation, one attendee mentioned a statistic he’d heard, “… that if all the farmers in the United States planted cover crops, that the land could absorb the C02 produced by all the cars in the U.S. every year.”  

“I’m familiar with that data,” Dr. Hatfield responded. “And it’s true.”   *


*I couldn’t find the study he referenced, so I did my own scrap-paper calculations. The average car emits about 5 tons of C02 per year. There are 2.13 million private, commercial, and municipal vehicles registered in the state of Wisconsin (not accounting for boats, jet skis, snowmobiles, ATVs, and tractors), which means that Wisconsin vehicles produce at least 10.7 million lbs of C02 emissions a year.

Various studies point to continuous cover crops sequestering about 1,000 lbs of C02 per acre per year at the low end with some sequestering as much as 3,000 lbs  of C02 per acre in rich soils. There are 15.2 million acres of farmland in Wisconsin. If every farmer in the state seeded cover crops, they could sequester about 7 million pounds of C02 per year at the low end. If Wisconsin farmers started practicing serious soil health, they might be able to sequester 14 million lbs of C02 per year. It’s one step, but it’s one that copuld collectively make a huge difference.