Sunday, January 29, 2012

Not All Composts Are the Same

Not all composts are the same. I know this sounds obvious, but I recently did a little experiment anyway just to see for myself. Last summer, I found myself back in the Sierra Nevada of California camping at an elevation of maybe 7,000 feet. We were near an impressive grove of old red firs. By the parking area I noticed that a pile of soil had fallen from the forest above an exposed bank of earth. It was dark and rich, very different than the pale dirt of the exposed bank. When I looked closer at the forest I realized that the soil was a thick matting of decomposing fir needles. It was then that I decided to conduct my little experiment.

I gathered a bag of the soil and took it home. Then I went looking for another large grove of trees with a thick and naturally composted soil. I found it near the San Joaquin River north of Fresno under some very large California sycamores. Finally, I gathered some of my own backyard compost made of yard leaves and kitchen scraps – pretty much a mix of everything urbanely biodegradable.

I then cleared a small area in the garden at the end of the summer and spread the three kinds of composts next to each other. Then I purchased a couple of varieties of lettuce and placed each one in the three composts. By Thanksgiving time, they were big enough to eat and I was ready to see if my little experiment would have anything meaningful to show for itself. I wanted to see if different kinds of soil would grow plants that tasted noticeably different.

In a way this seems fairly obvious, at least to serious gardeners. We, who have grown our own food for any amount of time, know quite well that a home-grown vegetable almost always tastes better than the same vegetable purchased from a supermarket. But being the experimentalist that I am, I wanted to see for myself in a direct comparison.

And I knew I would have a good chance to run a blind experiment on Thanksgiving. Erik and Tabitha were coming for the holiday and so were Alton and Bonnie (Kathy’s parents). They all agreed to participate in my little study. First, I cut enough of the lettuce for each of us to taste samples from each kind of compost. Then I arranged them so that only I would know which kind was which.

Almost immediately my participants could tell a difference in taste. Then Tabitha and Erik noticed a slight difference in smell too. Bonnie and Alton both came to the same conclusion. The lettuce grown in red fir and sycamore soils had a stronger bitter taste than the lettuce grown in the yard compost.

We decided that this might be caused by the more acid nature of the fir and sycamore soils. That’s my running hypothesis for the time being. In any event, the experiment was worthwhile. The differences were quite apparent. And it also made me think about soils in a broader context.

We truly are what we eat, and the things that we eat are made of the very substances of where they grow. Native animals and plants are not the only things that are tied to specific places. People are too. We don’t normally stop to consider what this means though. A typical day of a typical American involves eating food from all around the world – from soils that have no influence of any kind in purchasing decisions. We eat the food from cheap and expensive restaurants (and pseudo-restaurants) without an agronomic care in the world. I think this is bit naïve.

And I admit that I am mostly naïve myself on such issues. We should do better. Maybe we like the idea of owning an international body; fed, that is, from around the world. The only trouble with this thinking is that we really don’t know what it means. Does it mean that we are corporally (even viscerally) generic? I hope not. I expect that it partly means that we live in cages. The only internationally nourished animals that I know of are either kept in zoos or are otherwise domesticated and fed by humans. Wild animals all find their food locally.

But maybe I’m taking my little lettuce experiment too far. I’m not sure. Certainly “there are more things in heaven and earth than are dreamt of in [my] philosophy”. But then again, Hamlet was talking about heaven and earth. And so am I.

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