My guest for this episode is Dr. Laura Jackson, a biology professor at the University of Northern Iowa. Her focus is on issues of restoration ecology and sustainable agriculture. We touch on both of these in the conversation, leaning more towards the sustainable Ag side of things, then move on to cover the impacts of commodity based monocropping, and how the agricultural system in the United States is entrenched by many forces, from the political policies of national and state government, to the farmers, and also choices made by consumers in the grocery store. Within this are the seeds of why changing the way we grow food is so dang hard, but also that there is change on the way.
One of the things we talked about in this episode was increasing the organic matter of the soil by 1% and the impacts that has on water retention and absorption. I’ve always wondered what that means. How much is 1%? How much does that weigh relative to a given area, such as an acre?
Thankfully, our local agricultural newspaper, Lancaster Farming, continues to publish more information on sustainable agriculture, and recently published an article that answered this question. To increase the organic matter of an acre by 1%, you need around 40 tons of finished rotted organics, such as compost, to be worked into the ground. To get that 40 tons requires 80 to 100 tons of source material, such as the browns and greens from our yard or garden scraps. Thinking about all the bags of grass I’ve collected and worked into my compost, or that a cubic yard of compost weighs around 1,000 pounds, or half of a ton, just how much biomass is requires to increase the organic matter over an acre of ground. And, to go around with these numbers a bit, and that an acre of land is 43,560 square feet, and 40 tons is 80,000 lbs, we need to add just under 2lbs of organic matter for each square foot of land, or around 9kg per square meter.
It boggles my mind to think about what we’d need to do in order to restore organic matter, fertility, and water retention and absorption to the most degraded soils. But, that’s only as I imagine doing it all at once. What this does for me as a permaculture practitioner is to remember the ethics, so that I care for the earth. Use the principles to slow down my thinking, to use slow and small solutions of incremental change so I don’t burn out, and can adjust my design moving forward. To value renewable resources, provides a strategy of using biological processes to create the change. Wanting to create no waste, leads me to a strategy of recycling materials on-site. From there, come my techniques. What biological processes can I use? If the soil is hard and compacted, I can use deep rooting radishes, such as daikon, to penetrate down into the earth and break it up. Living in a temperate climate, leaving them in the ground they’ll freeze over winter, and rot in the spring, directly introducing organic vegetation into the soil where it’s needed, rather than digging it in. Tender cover crops, that easily winter kill, especially leguminous ones, can be planted in Fall, and then mowed in the Spring, leaving the roots in the ground, again increasing organic matter, where as the tops can be collected and added to the compost. That compost, going back to the idea of recycling waste on-site, can then be dug into Zone 1 garden beds, with other materials as a potting mix to grow seedlings, placed in the holes of new perennial plantings, or even spread on the ground as a mulch itself, or underneath other mulches.
These are all things I could do where I live, because it’s temperate, with consistent killing temperatures over the winter, down to single degrees Fahrenheit or around -15 degrees Celsius. Would these work for you? Maybe, maybe not. As I’m often reminded, it depends. And that’s why I focus on the ethics, and then the principles, as my foundational understanding of permaculture. These are the ideas from which all else descend.
Dr. Laura Jackson