Micro/Macro: Rethinking Agriculture on the Sustainable Scale
Part four of a conversation with the leaders of Somerville-based Green City Growers
This is the third installment of “Micro/Macro: Rethinking Agriculture on a Sustainable Scale,” a series examining shifting perceptions of agricultural practices. As interruptions to traditional food supply chains increase due to risks associated with factors such as climate change and changing global demographics, many are exploring innovative approaches to agriculture that will ensure greater food security. This series explores routes by which architects, urban planners, and ecologists can contribute to this dialogue of utmost importance.
The following is written by Brian Chilcott, Associate ASLA, who is a landscape ecologist at Sasaki. He has a sustained interest in agriculture that stems from his origins in rural Nebraska, on a 16-acre farmstead that was (and still is) teeming with biodiversity.
What is an ecosystem? What are its components and how does it work? As a landscape ecologist at Sasaki, such questions drive and inform my daily work. For too long, both the science and the popular notion of an ecosystem was narrowly focused on wild, undeveloped landscapes. Cities were cities. Farms were farms. Only naturalized landscapes were commonly studied as ecosystems. Today we know better.
The more we explore the makings of ecosystems, the more complex we find them to be. Even now, we have cataloged only 1.9 million of an estimated 15 million living species on earth. Most of those we have cataloged remain obscured in mystery as the complexities of their lives—their functional ecologies—still exceed our capacity for scientific description. This reservoir of biodiversity is the very core of my passion—protecting, celebrating and promoting it is the vantage point from which I approach all of our projects.
Humans rely on this reservoir of biodiversity for their very existence. Without the millions of species with which we share our beloved planet, we could not and would not exist. The scope and complexity of this dependence is truly astonishing. Even the human body itself is an ecosystem: about 3 pounds of the average human body’s weight is comprised entirely of bacteria. From the air we breathe and the fresh water in our homes to the medicines that keep us healthy, we depend entirely on the biodiversity of the planet.
Nowhere is our dependence more immediate and more apparent than with our food. Farms are complex, dynamic, and fascinating ecosystems. As farmers, we are the creators, the stewards, and the beneficiaries of the ecosystems. Historically, farms were managed as zero-waste cycles. Between the livestock and the produce, all forms of waste were processed and utilized as inputs. In healthy ecosystems, waste is a misnomer and maximum efficiency is the modus operandi. Vegetable waste feeds the livestock, livestock waste feeds the soil, and the soil produces the vegetables. But within this neat cycle are millions of unseen and underappreciated players with critical functional roles: agrobiodiversity.
The historic or traditional farm was a characteristically messy landscape with a mix of crops, pastures, fencerows, and woodlands that built a balanced ecology through the resilience inherent in diverse systems. Modern industrial farms, on the contrary, have resulted in ever-more simplified landscapes with fewer and fewer living components. The heterogeneity of the messy farm gave way to massive fields of single-species crops and isolated confined animal feeding operations.
The traditional small farm was teeming with biodiversity—especially insects. Pest species were present, but so was an abundance of beneficial insects: the predators and parasites that feed on pests as well as the pollinators that ensure fruit set. Over 100,000 different species including bees, birds, bats, wasps, flies, butterflies, moths, ants, beetles and bugs all contribute pollination services worldwide. Today, many industrial farms rely exclusively on only one species—the honeybee—which is highly susceptible to disease outbreak and hive collapse. Similarly, countless species of beneficial insects once kept pest populations in check, though most of them depended on adjacent non-crop habitats like hedgerows, woodlots, and meadows for their life-cycles. Our modern reliance on chemical pesticides has eliminated most of these species from farms while simultaneously selecting for resistant strains of crop pests.
Farms in the United States have increased fertilizer application over 700% in the past 40 years. In 2008, US farms also applied 516 million pounds of pesticides (up from 196 million pounds in 1981). As farms have shifted towards monocultures, a host of problems have arisen that impact not only the ecosystem but our entire society. The runoff of farm nutrients in the upper midwest, for example, is the primary contributor to Mississippi River eutrophication and the resulting hypoxia and ‘dead zone’ in the Gulf of Mexico. Pesticide application not only eliminates populations of beneficial insects, it can contaminate groundwater, kill fish and amphibians, and wreak havoc on the balance of any ecosystem. Bumblebees, for example, have declined by over 25% across most of the northern temperate world. The loss of genetic diversity in food crops through the ongoing extinction of heirloom and uncommon varieties threatens the very future of our food supply as climate change and emerging diseases make common varieties more and more vulnerable in an uncertain future.
Yet, in cities around the world, small-scale, environmentally and community focused farms are experiencing a renaissance. Small farms are emerging not merely as sources of food; in cities they are becoming repositories of our cultural and ecological heritage. They become educational landscapes and interpretive sites where urban children learn about food and about nature. They become part of our green infrastructure as well, providing ecosystem services rather than exporting pollutants. They bring communities together around the elemental joy of the pastoral landscape. With few exceptions, this has been happening organically, through the grass-roots efforts of impassioned individuals and with only limited intervention by design and planning professionals. Design and planning, however, can strengthen this movement. As urban centers continue to expand, so will the challenges and opportunities for urban agriculture.
Now more than ever, as we imagine innovative functional roles of farm landscapes within and around cities, we must seek to rebuild the complex landscape structures to support a robust agro-ecological system. As designers, we must strive to integrate sound science into the creative process and explore the spatial synergy between our natural lands, recreational lands, and our productive agricultural lands all at the interface of the burgeoning modern city. How can a stormwater basin serve as a source population for beneficial insect predators? How can the landscape of a public park intentionally rebuild pollinator populations adjacent to a community vegetable garden? How can we leverage diverse yet intentional native plant palettes to contribute mutual benefits with local farms? Can we design adjacent uses for maximum integration of beneficial biodiversity back into urban and peri-urban landscapes?
The design of productive urban ecological systems represents a new frontier for designers, and at Sasaki we have been pushing ourselves to lead the charge. In the heart of Shanghai, for example, our master plan for Zhangjaibang Park locates community gardens in a transitional space between neighborhoods and a public complex of wetlands, meadows and woodlands. This design serves for maximum exchange of biodiversity (Fig. 1). Similarly, one of Sasaki’s current project in the Philippines envisions a community agricultural corridor abutted on both ends by natural areas that will function as source populations for beneficial insects and birds (Fig. 2). By continuing our pursuit of these ideals across our practice, we challenge the dichotomy between what is urban and what is rural, what is built and what is wild. We imagine an ecosystem that is both city and farm, buzzing with all kinds of life.
Photo courtesy of Gena Morgis