Soil Health Report: Where We Are and Where We Want to Go

Soil is produced and sustained through a complex web of interactions, involving everything from the ancient basement rock of earth at one end of the scale down- or up rather- to minute but super-abundant micro-organisms, as visible in this mid-century scientific diagram.

Thanks to one of our amazing volunteers, Krisi Olivero, who is- among other things!- a soil scientist by profession (see her soil lab’s website for more information: Alter Eco Farms) we were able to get a snapshot of the health (or lack thereof!) of the soil at our St. Elmo site along the Virginia Avenue Greenway. Krisi took soil samples from along the hillside and examined them for signs of microscopic life, in order to give us an idea of where we’re starting from and what kind of work we (and our microbial and macrobiotic friends) have cut out for us in the coming months and years. Soil health is generated by many interlocking factors, but among the most important is the presence, diversity, and overall health of the tiny organisms that, in healthy soil at least, fill just about every nook and cranny of the soil structure, interacting in a complex dance of consumer and consumed, cycling nutrients into the wider ecosystem, encouraging water movement, interacting with larger organisms, and many other roles. To overgeneralize a bit, soils tend to be either dominated by bacteria or by fungi, both consumers and recycling agents of organic matter; for trees and shrubs- our target plants for a full-fledged food forest- we want fungi to dominate.

So what does our soil health profile look like? Well… we’re basically starting from scratch! Krisi found bacteria not just dominating but just about the only game in town, with no traces of fungal activity; nematodes (one of which is visible below, taken from a different, and healthier, sample) were also absent, along with various other groups of microorganisms that we’d like to see. Just about the only other microorganisms present were a few scattered protozoas, including some ciliates, single-celled protists that are normally found in wet or even aquatic contexts (you may remember the ciliate Paramecium from biology class). Obviously our hillside is not a wetland of any sort, but the soil is pretty anoxic- oxygen deprived, not because of moisture but because of compaction.

Why is the soil on our hillside so poor? A quick look at the current ecology of the site gives a pretty good idea: aside from the strip of leyland cypresses along the north side, all we’ve got is lawn grass, with a few brave ‘weeds’ popping up here and there. For decades the only maintenance this piece of land has received has been regularly close-cropping mowing, using heavy, fossil-fuel powered equipment, no doubt a major cause of the soil’s compaction (though other factors have played a role to be sure). Any autumn leaves that previously fell on the site were probably all blown away before they had any chance to decompose and add new organic matter to the soil. Instead, the only real inputs have been the fragments of cut grass, and the odd rabbit that makes its way up the slope and adds its droppings to the soil. With almost no above-ground species diversity, and most additional organic material being actively removed, the result is pretty much a microbial wasteland, dominated by extremely hardy bacteria and not much else.

Fortunately Krisi did not find any dangerous pathogens, so at least we don’t have to worry about removing or combating microorganisms we don’t want (though we do want to reduce the dominance of bacteria). Our job now- well, our part in the drama is pretty minor, it’ll be all the other organisms and processes that do the vast majority of the work- is to feed in a mixture of organic materials: dead leaves, mulch, cardboard, composted manure, ordinary compost, logs, and, over time, an increasing number of plant species with their own soil remediating roles. By changing the environment, and, especially important, changing the maintenance regime, the microbial composition of the soil will change, and its health will improve. Not overnight, but we should start to see results in coming months and over the next couple of years, as natural processes and ecological entanglements convert the raw material we supply into healthy soil.

Our hillside is of course not unique: urban, suburban, and rural America alike are filled with very similar ecological deserts. Some forty million acres of our country are covered in lawn grass, the overwhelming majority of which has no function beyond looks. It feeds no animals, no children play on it, nothing but a handful of species of grass grow in it, with a poor microbial biome underneath; to make matters worse, most lawns are huge energy sinks thanks to the energy consuming machines used to keep it neat and trim, as well as the various chemicals so often applied to kill any biological diversity that dares raise its head, all of it frequently topped off by all the water expended in keeping turf grass alive in dry periods.

It doesn’t have to be this way: instead of ecological wastelands whose upkeep pushes our shared planet one step closer to biological collapse and devours resources that could be used for all sorts of other things, we can transform at least a portion of those forty million acres into productive ecosystems for human and non-human health, cycling organic material back in, not consigning it to a landfill, and feasting on the literal and metaphorical fruits of the abundance that will eventually result. One of our central goals with this food forest project is to show to ourselves and our neighbors that such transformations really can be done, in the heart of the city, on land that has been abused or polluted or just largely ignored for many, many years. It’s not going to be easy- as we’ve seen, we don’t have much with which to work right away. But over time, and with attentive care on our part, feeding and letting be the vast web of living things visible and invisible to our naked eyes, life will flourish and feed us and other living things, growing a better world one city lot at a time.