** Notes from the Farm: July 15 2021
Reflections on composting
It's a warm day and a faint whiff of ammonia rides a breeze through pinon and juniper along a wash at Polk’s Folly Farm. Trevor (LN) of Reunity Resources stands with one foot on a giant pile of horse manure and wood mulch, wielding a three foot thermometer, explaining to a group of a dozen people how to insert the device into the pile regularly over the coming weeks to make sure the compost gets to 131 degrees and cooks there for a number of days. He explains how appropriate temperatures are key to good compost production hot enough to kill weeds, parasites, and pathogens. He also mentions that the ammonia smell is an indicator of too much nitrogen in the compost mix.
This is the second in-person workshop in a series co-hosted by the Quivira Coalition and Reunity Resources as part of a Rural Development Grant focused on diverting waste from rural landfills and repurposing biodegradable materials on farms for compost. The morning session focused on a method known as aerated static pile composting. The small crew of participants got to help construct an aeration system of perforated PVC pipes and a bouncy house blower. Then, our farm team mixed animal manure (a nitrogen source) from the barn and wood mulch from the transfer station (a carbon source) to create a 5 foot tall, 25 foot long pile atop the aerator. We wetted the pile, then covered it with a layer of just wood chips to help keep moisture in the pile. The pile will take 3 to 5 weeks to compost, then can be shared with area farmers, or applied to degraded areas on our own pastures.
While we have produced compost on the farm for years now, this particular aerated static pile method is new to us. We typically will create large windrows and turn them periodically to aerate the parts at the bottom of the pile. This system is aerated by the blower, so doesn’t require the extra tractor time. We’re excited to compare the results to previous efforts.
Some of you may be familiar with composting, but just so we’re on the same page, I’ll borrow a few quotes from the new technical guide published by Quivira and Reunity Resources (https://quiviracoalition.org/rural-dryland-composting/) about the process. Composting takes advantage of the natural decomposition processes that are performed by microbes and larger organisms like nematodes, worms, mites, sowbugs, springtails, ants, and beetles. Tailored combinations of feedstocks, water, and air help the decomposition process along. While carbon based materials all eventually break down in soil, with composting, we also make the process occur above the soil at an accelerated rate to produce a useful soil amendment quickly and put it where it is needed most! Between 50-75 percent of the carbon in the feedstocks (horse manure and wood chips at the workshop this weekend!) put into the compost pile is lost as carbon dioxide, but all other nutrients remain, making the compost enriched in nutrients
compared to the plant and animal material that went into it. This is what makes compost a really good, stable, long-term fertilizer.
Finally, I’d be remiss if I didn’t share ideas about how composting is key to creating climate resilience, reducing emissions from our food systems, and restoring degraded ecosystems. Again, from the new guidebook -- Food production is intimately tied to the carbon cycle and therefore with climate change. For example, in 2009, emissions associated with food production, processing, transport, and disposal accounted for 13 percent of US greenhouse gas emissions. Approximately 42 percent of US greenhouse gas emissions are associated with the energy used to produce, process, transport, and dispose of the food we eat and the goods we use (Opportunities to Reduce Greenhouse Gas Emissions through Materials and Land Management Practices, 2009).
Sending organic waste to landfills results in the highest greenhouse gas emissions scenario when compared to composting and anaerobic digestion with gas or heat capture (Nordahl et al., 2020). Moreover, diversion of organic waste to compost and application of that compost to agricultural lands results in the uptake of greenhouse gases because soil health improves. In turn, healthy soil leads to healthier, more productive plants. Specifically, applying compost increases plant productivity due to improved soil structure, improved water availability, and improved nutrient availability. These improvements made through the application of compost can be long-term (Ryals et al., 2014).
So, for these reasons, we’re champions of compost, and proud to be the dirtiest farm on the mountain.