This post is one of a series created as a part of our Kalamazoo College Senior Capstone Course, “Slow Farming: Just, Joyful, and Resilient Agriculture.” Due to the COVID 19 pandemic, we are teaching this course online in 2020 and making the blog post portion available to community members as well.
Hello Slow Farmers!
Well, we got Winter back for a few days last week but it looks like Spring has returned to us again. All across the farm, our plant, animal, and insect friends are waking up from their winter dormancies. This includes our friends in the soil, the microbes. One of the things we’ll be doing this week is tending to our garden soils and getting them ready for planting. What this soil preparation looks like is different in each of our garden areas depending on the soil type and garden design. Next week I’ll show you some of the different cultivation and planting strategies we use to care for our soil. This week I’d like to focus on compost and how it can be part of the solution for three major problems in our industrial food systems: food waste, nutrient deficiencies, and fertilizer runoff.
In our live call last week, I shared an infographic with you that showed the connections between nutrients in the soil, nutrients in the bodies of plants, and nutrients in our own bodies: http://www.fao.org/resources/infographics/infographics-details/en/c/358223/
I’d like to focus a moment on one of the “macronutrients” depicted in that diagram: nitrogen. Nitrogen is a critical element for plant growth in part because it is essential for photosynthesis, the process by which plants produce energy in their bodies using sunlight. In the image below you see a representation of the photosynthesis equation that depicts plants’ taking in of carbon dioxide and water and converting those substances into sugars (C6H12O6) that are used to build the plant’s body and oxygen that that is released back into the air. Of course, this diagram is simplistic and misses a lot of the steps! If you remember our conversation last week, you might notice one critical piece that is missing from this diagram–the exuding of sugars back into the soil through the plant roots to feed the microbial community that is making an array of nutrients in the soil available to the plant.
But wait, where’s the nitrogen in this process? Well, the process by which plants make sugars out of carbon dioxide and water requires a substance called chlorophyll and nitrogen is one of the elements of that chlorophyll molecule. Nitrogen is also essential for plant proteins that build plant structure, for energy transfer within the plant, and is a fundamental component of DNA. So, no nitrogen, no plant.
Throughout this course, I’m going to be talking about how we look to the systems, processes, and relationships of nature as we design and manage our gardens. (Why? Well, because nature works! If you haven’t noticed, we have are living on a complex, beautiful, and highly functional planet that works incredibly well when humans aren’t disrupting the systems that create and support all of its life.)
So let’s look at the system of nitrogen cycling that Mama Nature uses to support photosynthesis in plants. (And remember that plant photosynthesis is critical to supporting all animal life as well. Since we “higher order” organisms can’t make our own energy using sunlight, we must get our energy by eating plants or eating other animals that eat plants.)
Take a few minutes and look at this diagram. What do you notice? What are your first impressions? Follow the arrows around the diagram with your eyes. What additional things do you notice as you look more carefully? What questions arise?
Here is a photo of legume root nodules on a bean plant from my garden. Inside these nodules, there are bacteria doing the work of supplying nitrogen to this plant:
Now let’s take a look at the human-constructed nitrogen cycle that is fueling most of our industrial crop production today: https://www.youtube.com/watch?v=pzFZ9TYizaw
As you watched this video, what did you notice? What were your first impressions? What images and/or words stood out to you? Watch the video one more time. What do you notice on your second watch? What questions arise for you?
Okay, now take a listen to this short radio story on the development of the Haber-Bosch process of producing nitrogen fertilizer using nitrogen from the air and hydrogen from natural gas and other fossil fuel sources. As you listen, have a blank piece of paper near you and jot down the claims (or main points) you hear being made throughout the piece.
Now, look back through the list of notes you jotted down. What messages stand out to you? Which relay facts and which are speculation? What additional information might you need in order to verify the claims that are made? What worldviews and values are represented in this piece? Whose voices and perspectives are missing?
Notice, too, how your own positionality, background, and academic studies shape your responses. What experiences and beliefs are you drawing on as you evaluate the messaging of this radio story?
K students, I’m going to ask you to take a break here, go to our Moodle and share your responses to the questions I’ve asked you throughout the first section of this blog post in the Harvest of Joy Farm Week 4 forum.
Just my personal opinion, but I think that one of the dumbest parts of our industrial food system involves the extraction of fossil fuels to create chemical fertilizers to fuel farming systems that destroy the life in the soil, thus creating the need to apply more chemical fertilizers since plants can’t get the nutrients they need from the soil food web if the soil food web is broken. Without life to hold the nutrients in the soil, we have nutrient run-off into waterways, devastating aquatic ecosystems. So we have to apply more chemical fertilizers because those we previously applied have been leached out of the soil and are no longer available to plants. Who might benefit from this fertilizer treadmill, do you think?
The other dumb thing is that we use these chemical fertilizers to grow a bunch of food, a lot of which never gets eaten. In the US, it is estimated that 40 percent of the food that is grown is wasted. And much of that food ends up in landfills where it produces methane gas that contributes to climate change. So the process of creating chemical fertilizers creates toxic waste products, the process of using chemical fertilizers creates toxic waste products, and then we take food that we grow with those fertilizers and make more toxic waste products out of it!
Perhaps thinking about nature’s approach to “waste” could help us re-imagine our soil fertility systems in a way that makes more sense: https://www.youtube.com/watch?v=DBgYfkuydaI
Waste is not a concept that Mama Nature subscribes to. In natural ecosystems, one organism’s waste is another’s food. There are lots of ways that we can apply this principle of “no waste” in our farms, gardens, communities, and daily lives. One way is through composting. Or, rather, many ways are through composting, for there are many ways to compost. Here are three composting strategies that we use:
Cold Composting: Letting organic materials decay over time without a lot of management or interference. Cold composting can be done in piles or through other methods such as sheet mulching (layering organic matter over an area that you want to turn into a garden next year). Or you can continue to add layers of mulch to your already established garden and let the decomposers in your soil break them down over time.
Pros: Easy to build and maintain.
Cons: Won’t kill off pathogens or weed seeds. Takes a long time to fully break down.
Hot Composting: Mixing organic matter together in the right ratio (along with air and water) to promote fast microbial population growth. As the microbes (like bacteria) feed on the organic material and reproduce, they release heat, which can bring the pile up to 130 degrees F or higher. In an intensive hot composting process, the temperature is monitored and the compost is managed to maintain optimal temperatures (which are really just indicators of optimal microbial populations). Maintenance can include turning, watering, and/or adding materials to keep the microbes happy.
Pros: Because the pile gets so hot, pathogens and weed seeds are destroyed and because decomposer microbes are maintained at optimal levels, the compost process happens much more quickly than in cold composting.
Cons: More labor intensive to build and maintain. If the pile gets too hot, plant-beneficial microorganisms can be killed off as well.
Vermicomposting: Using worms to break down organic materials. This method uses specific types of worms that feed heavily on decomposing organic matter. As bacteria soften and begin to breakdown the compost materials, the worms suck in a mixture of the bacteria and decayed organic matter and poop out worm castings, which are rich in both nutrients and beneficial microbes.
Pros: Can be done in small spaces, such as indoor containers. Produces a very nutrient and biologically-rich compost. Materials can be added frequently in small batches.
Cons: Does not kill pathogens or seeds. Requires some maintenance (worms are alive, after all, and will die if they don’t have their basic survival needs met).
But any given compost pile might not fall neatly into one category or another—it’s a spectrum! For example, piles may heat up initially, then cool down, and as they cool, the worms move in to finish the job.
Here’s an overview of some backyard composting basics from the Rodale Institute: https://rodaleinstitute.org/blog/backyard-composting-basics-a-cheatsheet/ One thing that they suggest that I might skip is putting your compost pile on a pallet. Yeah, it will give you better air circulation at the bottom, but then you are going to have to extract your compost from the pallet or vice versa. I don’t know, I haven’t tried it, so maybe it isn’t as much work as I imagine that might be. If you try it, let me know!
One type of composting that I love to do is vermicomposting, composting with redworms. This Cornell webpage contains a 9 minute video that explains why vermicompost is so good for plants: http://cwmi.css.cornell.edu/vermicompost.htm.
I put together a few videos demonstrating my process of building and maintaining vermicompost bins. You can view them here: https://photos.app.goo.gl/qTTWgXaUs2binFTj9
K students, I’d like to hear from you about your experiences with and thoughts about food waste and composting. Please go back to the Moodle and add your thoughts about food waste and composting to your previous forum post (you can just reply to yourself). Have you done composting in the past? If so, how did you do it and how did it go? What compost methods might work for you where you are living currently? What challenges and obstacles to reducing your food waste and/or composting do you face? What would you need in order to overcome those challenges?
Next week we are going to talk about other strategies for keeping soil healthy and what health soil has to do with climate change, so stay tuned!