Connections: Local Soil

Sally Brown

Sally Brown
BioCycle January 2013, Vol. 54, No. 1, p. 52

 

Not too long ago, the U.S. Department of Agriculture issued a new and improved version of their food pyramid. They changed the graphics and the relative abundance of fruits and vegetables but they left out the dirt — the missing soil piece on the bottom to stabilize the pyramid and anchor the vines.

At the same time, a whole new vocabulary has emerged today related to eating better. These include terms like locavore, CSAs (community supported agriculture), regional food systems and food desert. The good terms (the first three just mentioned) conjure images of happy people growing tomatoes of all shapes and sizes, weekly delivery of bags of goodness, eating healthy meals that include greens that you can’t identify and potatoes that come in my school colors (purple and gold). Food deserts, the bad term, brings to mind terrible places populated by convenience stores — home of energy drinks and motor oil and not Chioggia beets. None of these terms, just like that revised pyramid, mention nor conjure any images of soil.

Search the public health literature on eating fresh and community agriculture and that same missing link is evident. Landis et al. (2010) talked about how people in North Carolina who got food from CSAs ate more servings and a more varied menu of fruits and vegetables than people that shopped at the supermarket. Exactly what the USDA pyramid wants you to do and no mention of soil. Blain et al (2010) discussed community gardens and how the people that participate in these eat better than the people that shop in the supermarket. Yet another article (Powell et al., 2012) talks about the improved quality of tomatoes grown to taste good rather than look good. No mention of dirt yet again.

Upon closer look, one of the common themes of all these new food terms and the literature is the emphasis on local. Local is the key common denominator. Food grown locally is generally more diverse and more affordable than what you find in many stores. You also eat a healthier assortment of it. This is true  if you shop at a supermarket rather than a convenience store. Locally grown, eaten when ripe, garden plots, community agriculture are all terms that refer to food that comes from around the corner rather than around the world.

Time For A Soil Campaign

I think that it is time for us to start a local soil campaign. Local soil, soil that we make just around the corner or certainly within driving distance from those CSA farms and community garden plots, has the potential to anchor that pyramid on very sturdy ground. Locally crafted soil is healthy and sustainable, as good for the planet as those locally grown greens are for you. The other critical point here is that all of the new “foodies” wanting to grow their own have a much better chance of success planting in locally crafted soils. With well-made soils, the plants need very little else to prosper.

There are a whole bunch of recipes for making soil. The traditional one taught in soils science class makes the crockpot look like a microwave: Parent material, topography, climate, biota and time (here measured in thousands of years rather than months or weeks) are the key ingredients for soil made in nature. I would not recommend relying on this approach to encourage the local food movement.

However, it is possible to speed this up with no loss of quality. The key is organic matter. Organic matter that is good for soil generally originates as something that was grown in the soil in the first place. It can also come from something that ate the thing that was grown in the soil. Soils are not so picky that they can tell the difference between organic matter derived from a community garden plot or a supermarket. A wide range of organic materials that we can’t eat all have a role to play. Bottom line: Organic residuals are the key to any recipe for making soils worthy of being called local and even more important, worthy of growing food in.

Conveniently for the nascent local soils campaign, a majority of people in the world live in cities. This suggests that many of the places where local foods are grown are also either in close proximity to or actually within city limits. Such a concentration of people and local food production also means that a majority of the key ingredients for locally grown soils are also located in urban areas. One of the early and most influential proponents of the local food movement, Will Allen from Growing Power (http://www.growingpower.org/), came to Simon Fraser University in British Columbia, Canada a while back to talk about local food. He noted that the thing that was lacking in urban areas for growing food was good soil.

This led to a second symposium on mid-scale composting in the city — aka making local soil. I was invited to give the plenary at this symposium (http://www.youtube.com/watch?v=BGs4ykyqW1Q). You can also see the one comment posted on that link (scroll to bottom) about the evils of toxic sludge. Municipal biosolids are a feedstock source for making local soil, as are other municipal, commercial, institutional and agricultural organics. However, many local food advocates only trust the compost that they make. Compost produced out of centrally collected yard trimmings and food scraps or biosolids has the perception of being the local food equivalent of the Styrofoam tomato.

While every community gardener can contribute feedstocks for making compost, it is really okay to entrust local soil production to professionals.  Backyard composting is a great thing and a compost bin at the community garden ranks high. Nevertheless, I would argue that centralized residuals composting and processing facilities are just as good if not better. It takes time to learn how to blend different residuals and control the stabilization process to make good organic matter. The centralized facilities have this knowledge and in many cases are regulated to make sure that they use it. They also have trucks, turners and temperature probes. Centralized operations are better equipped to get these organics in the first place. This is great and has enabled many facilities to get enough feedstock to manage.

However, many of the centralized facilities have spent too much time talking to their municipal contacts to get the feedstocks and too little to the people that actually generate the feedstocks and who need the organic matter to ensure their local food plants flourish. We, and here I am including myself in the group of professional organic recyclers and composters, have to stop being the bad guys for the local food movement and start being the go to place for locally sourced soils. We have to inform people that the soils being produced are not from toxic industries but from their own residuals. The local food movement needs to understand that we’ve got their backs (or roots) with the foundation they need: local soil. And finally we have to let people know that our version of local soil is akin to the Brandywine or Cherokee Purple varietals of the tomato, not the Styrofoam version.

Sally Brown — Research Associate Professor at the University of Washington in Seattle — authors this regular column. Email Dr. Brown at slb@u.washington.edu.

References

Blain, T.W., P.S. Grewal, A.Dawes, D. Snider. 2010. Profiling community Gardeners. Journal of Extension  48:6

Landis, B., T. Entwisle Smith, M. Lairson, K. McKay, H. Nelson, and J. O’Briant. 2010. Community-Supported Agriculture in the Research Triangle Region of North Carolina: Demographics and Effects of Membership on Household Food Supply and Diet. Journal of Hunger & Environmental Nutrition 5:70-84

Powell, A.T., C. V. Nguyen, T. Hill, K. Lam Cheng, R. Figueroa-Balderas, H. Aktas, H. Ashrafi, C. Pons, R. Fernández-Muñoz, A. Vicente, J. Lopez-Baltazar, C.S. Barry, Y. Lui, R. Chetelat, A. Granell, A. Van Deynze, J. J. Giovannoni, and A. B. Bennett. 2012. Uniform ripening encodes a golden 2-like transcription factor regulating tomato fruit chloroplast development. Science 336:1711-1715

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