SOLIDIFYING THE INVISIBLE WASTE AS PART OF THE FOOD SYSTEM EVA STRICKLER

Solidifying the Invisible Waste as Part of the Food System

BY EVA STRICKER, PH.D.

The “circular economy” of food and waste can have major benefits to the food system.

Let’s begin at the core. An apple core, to be specific. You’ve enjoyed a crisp, crunchy, sweet apple, and your digestive system is working to break down the sugar compounds to build structures for your cells and use the energy to drive your metabolism. Now what? So what are the comparative effects of disposing of the apple core by goat, worm bin, or dump? Aside from the benefits to the food system and soil health already mentioned, the carbon dioxide and

You could ask your neighbor if it’s all right to feed the apple core to her backyard goat. Unlike us, goats and other ruminant animals such as cows and deer have four compartments in their stomachs, hosting diverse microorganisms that are able to digest plant parts that are indigestible to us. That’s why goats are able to survive eating leaves and grasses, but we cannot. The microbes in ruminants’ stomachs do not need air; they use a process to break down the sugar compounds, which releases gases such as methane and carbon dioxide. Ruminants then burp or fart these gases out into the atmosphere. However, much of the apple core was transformed into compounds that helped build the animal’s body and drive its metabolism. This goat can help control weeds and eats grass on land unsuitable for crops, and you may even later enjoy some goat’s milk cheese.

Alternatively, you could toss the apple core into your backyard worm bin or into a greenbucket compost. This provides crisp, crunchy, sweet food to millions more organisms to decompose. Just like you, worms and many microbial organisms use enzymes to break down the complex sugar compounds into building blocks for their cells and energy for their metabolism. Just like you, they also need water and oxygen, and they release carbon dioxide as a waste product. Despite the waste, much of that apple core was transformed into worm or microbial bodies that help create new carbon-rich compounds in the soil. Many of these compounds provide a slow-release fertilizer to your garden or crops, act as a sponge to absorb and hold precious rainfall, and help build soil structures called aggregates that can withstand erosional forces such as wind and water. All of this builds soil health.

Finally, you could toss the core into the garbage, right next to the plastic sticker you peeled off, a produce bag, a banana peel from breakfast, and a greasy pizza box. The garbage bag will be transported to a landfill, where it is smashed down with everyone else’s; there will be no air flow to the microbes now trapped in the bag. So, instead of the microbes that function like those in the soil (using oxygen in the air to decompose the apple core and releasing carbon dioxide), different microbes will drive the decomposition process. These microbes, like those of the goat’s stomach, do not use oxygen, and they release methane as invisible waste instead. The apple core releases methane gas and provides no benefits to a goat or to the soil.

A critical value is how to tie the food system to the fight against climate change.

Above: A farmer at Polk’s Folly Farm in Cedar Crest, N.M. spreads compost as a soil amendment. Below: Livestock are one potential pathway for decomposing food waste.