Urban Agriculture and Food Security
Note: This webpage is for instructional purposes only and was not actually commissioned by Wisconsin government agencies.
Hypothetical task force Report prepared for the United States Department of Agriculture (USDA)
UW-Madison Task Force Members:
Jack Moser, Senior, College of Letters & Science
Ben Steiger, Senior, College of Letters & Science
Urban agriculture practices are increasingly being integrated into policies focused on improving food security and vegetable intake in metropolitan areas of the United States. Successfully implemented urban agriculture can overcome geographical limitations and effectively convert unused city land, in the form of rooftops or vacant lots, into beneficial greenspaces through the creation of gardens and farms. The GROW Biointensive method, created by John Jeavons, can build adequate soil, using low quantities of water and fertilizer inputs while generating high crop yields in a limited space, requiring only 4000 square feet (ft2) to produce a fully functioning small-scale farm. Dark green vegetables experienced a 0.46 pound per square foot (lb/ft2) improvement in average yield using the GROW Biointensive methodology compared to conventional crop practices, while orange vegetables had a 0.27 lb/ft2 increase in average yield. Additionally, these crops, and berries and grapes, require low amounts of land to be productive relative to conventional agriculture procedures. Utilization of urban rooftops in tandem with the creation of mini-greenhouses may be best suited towards producing the highest yield of these crops in a limited area. To alleviate urban food security and improve vegetable intake, particularly amongst low-income subgroups, urban agriculture policy interventions should incentivize cost-effective urban agriculture production, and distribution of generated vegetables to low-income, food insecure urban populations.
|This is John Jeavons, creator of the GROW Biointensive method.Source: http://www.johnjeavons.info/john-jeavons.html|
Food security in the United States has become a hot-button issue in recent years, particularly as it pertains to feeding urban populations. The United States Department of Agriculture (USDA) defines food security as the “access by all people at all times to enough food for an active, healthy life” (Coleman-Jensen et al., 2016). As of 2015, the USDA reported that 87.3% of US households were food secure, leaving a remaining 12.7% population subgroup that is food insecure. Many food insecure households participate in food assistance programs, such as the Supplemental Nutrient Assistance Program (SNAP) and SNAP for Women, Infants and Children (WIC), that provide food aid which would otherwise be non-existent; however, more must be done to further bridge the gap in attaining adequate food and nutrition (Coleman-Jensen et al., 2016).
As much of the country’s population continues to concentrate in urban areas, focus on improving food security in these regions is increasingly urgent. The USDA estimates that 12.2% of households in metropolitan areas experience food insecurity (Coleman-Jensen et al., 2016). Increasing vegetable intake is a popular area of discussion for policy creation, as metropolitan areas face geographical constraints that lead to decreased access to healthy foods, a phenomenon that is commonly characterized as a “food desert” (Treuhaft, 2010). Urban low-income populations face particularly enhanced challenges to obtaining proper vegetable intake due to high costs and lack of access (Treuhaft, 2010). In its Healthy People 2020 initiative for improving widespread population health in the US, the Office of Disease Prevention and Health Promotion (ODPHP) set a target of 1.16 cups of vegetables per 1,000 calories, and low-income populations are short of this goal by 0.33 to 0.43 cups (ODPHP, 2014). A current political focus is to find methods of increasing vegetable availability in urban areas to improve vegetable intake in these regions with a focus on low-income subgroups, and reduce overall metropolitan-based food insecurity.
Urban agriculture (UA) is one essential component of increasing vegetable availability and alleviating urban food security concerns. To meet vegetable intake demands, conservative estimates point to a minimum consumption target of 300 grams per capita per day produced by land dedicated to UA. In the US, this would require about 1.3% of total urban area to produce vegetables to meet the intake goal for the urban poor (Badami et al., 2015). There are several UA methods in practice that attempt to overcome the restrictions of low land availability for agriculture. These approaches center generally on three different styles: ground-based agriculture, comprised mainly of community gardens on vacant urban lots; rooftop agriculture, which capitalizes on its elevation for improved sunlight capture and avoidance of ground-level contaminants; and controlled environment agriculture, utilizing greenhouses to create optimal light, water and climactic conditions (Ackerman et al. 2012). Other applied practices include hydroponics and vertical farming, which emphasize optimal water usage and irrigation implementation for highest yields. To optimize input costs and production, ideal soil conditions, water and fertilizer management, and sunlight availability must be maintained across the UA procedures. The GROW Biointensive method, founded by agricultural researcher John Jeavons, has been employed by over 140 countries around the world to improve soil fertility, reduce water use, and create higher crop yields (Jeavons, 2012).
A literature review of the Ackerman et al. study gave us our initial insight into the GROW Biointensive method and its possible use in UA. Through this review we hypothesized that the GROW Biointensive method, in tandem with other available UA practices, can help solve food security issues by increasing the availability of healthy foods at a low cost.
The goal of our research is to find the best combination of the GROW Biointensive method with other forms of UA to help improve food security, focusing on vegetable intake, that can be applied across metropolitan areas in a cost-effective manner.
Land Areas for Urban Agriculture: Previously published literature on UA revealed two distinct land areas in metropolitan regions where crop production can occur. These two areas are rooftops and ground-based vacant lots. Literature also discussed the use of controlled environment agriculture in UA.
- Ground based: Ground-based UA focuses on the use of vacant lots and buildings, public or privately-owned, for space to grow crops. Though high quantities of vacant land are available in cities, the land must be suitable for UA, eliminating protected spaces or other re-purposed land. This land must have adequate sunlight and space. Much of these areas are converted into community gardens, developed by initiatives such as the Urban Garden Program (Walker, 2015) and the Urban Agriculture and Openspace for the Greening of Detroit (Atkinson, 2012), both in Detroit, MI. These programs can successfully transform unused public land into greenspace to increase the supply of healthy food in urban areas, and place the focus on improving food security into communities by involving a range of local residents, from elementary school students to adults. Privately owned land also provides an opportunity for crop growth, involving the use of incentives, such as tax breaks for converting land into greenspace, or conversely tax penalties for failing to make use of the lots. Soil quality and contamination is a big issue on the ground, as pollutants such as lead or other metals may render the land unsuitable for food production (Ackerman et al., 2012).
- Rooftop: With a high concentration of buildings in urban areas comes a great opportunity for rooftops to be transformed into productive farmland. Though land on the ground may be limited, flat rooftops are ubiquitous and largely free of the potential contaminants and weeds that make ground-based agriculture problematic. Access to high levels of sun exposure is advantageous, although challenges associated with attaining proper soil depth and nutrient levels can be difficult to overcome, as can physical obstacles such as increased wind susceptibility and transport inconveniences (Ackerman et al., 2012).
- Controlled Environment Agriculture: In order to produce year round, greenhouses can be used. They can keep climatic variables such as temperature and precipitation constant. Soil quality and nutrient levels can also be maintained, while outside contaminants can be mitigated. There are potential high-energy and material costs associated with large greenhouses (Ackerman et al., 2012). The creation of mini-greenhouses may be simpler and more cost and energy efficient (Jeavons, 2012).
GROW Biointensive Method: John Jeans (pictured above) has created a technique known as GROW Biointensive Sustainable Mini-Farming, which focuses on soil fertility, allowing for increased crop yield with less water input. This method not only builds soil, it allows for preservation of the soil over years. This is hugely important because according to Ecology Action, for conventional farming methods, every pound of food eaten results in 6 to 24 pounds of soil lost from water and wind erosion (Ecology Action, 2006). This method miniaturizes food production in a closed system while staying away from the use of chemical substances. Jeavons’ method follows eight techniques, aiming to build fertile soil faster than in nature, use less water, and increase crop yields (Jeavons, 2012):
- Start with deep soil preparation to develop good soil structure using double-digging to create raised beds. Minimum size of the bed should be 3x3ft, but can be larger. The goal of double-digging is to loosen the soil to 24 inches below the surface. This technique aerates the soil, facilitates root growth, and improves water retention. After the structure has been established, double-digging is no longer necessary and soil upkeep can be maintained through surface cultivation, which loosens the upper two inches of the soil.
- The best source to start off this soil with is compost, but it should only be added before or during the initial double-dig. Compost helps create soil fertility and provides nutrients.
- Close plant spacing. Seeds should be planted diagonally offset or in a hexagonal spacing pattern, with equal spacing between the seeds. Seeds should be planted at a depth equal to its thickness.
- Companion planting. Planting certain plants alongside others can improve yield.
- 60% of the crops planted should be carbon-efficient crops, which mostly creates significant carbonaceous material for composting. Excess yield can be used for food.
- 30% of the planted crops should be calorie-efficient, which provide a lot of calories in the form of food.
- The use of open-pollinated seeds. This preserves genetic diversity by having no restriction on pollen flow.
- The last technique is the combination of the whole system. Every component of the system must be used together to avoid soil depletion. This is an all-in practice.
GROW Biointensive Results
Overall: Jeavons’ method is successful in its goals of quick soil building, using less water, and increasing crop yield. The method can end up building soil 60 times faster than would be possible in nature. It does this using 67-88% less water, over 50% less purchased organic fertilizer, and 94-99% less energy than commercial agriculture per unit of production. This method also increases soil fertility by more than double, with a 200-400% increase in caloric production per unit of area, as well as a doubling of income per unit of area (Jeavons, 2012). Only 4,500 ft2 is necessary for a fully functional mini-farm.
Crop Yield Results: Specific crops may have a greater increase in yield by using this method than other crops. According to Figure 1 , vegetables such as those that are dark green or orange, dry peas and beans, and starches, as well as other vegetables, such as artichokes, all can see large increases in yield under this method when compared to conventional practices. Dark green vegetables have one of the largest differences in yield, rising from 0.49 lb/ft2 to 0.95 lb/ft2. The fruit with the greatest increase in yield is grapes, increasing 0.45 lb/ft2 from 0.2 lb/ft2 (Ackerman et al., 2012).
|Figure 1: Average yield of crop based on growing method. Vegetables: Dark Green - broccoli, collard greens, escarole, kale, lettuce (leaf), mustard greens, spinach, turnip greens. Orange - carrots, pumpkin, squash, sweet potatoes. Dry Bean & Peas - dry edible beans, dry peas and lentils, lima beans. Starchy - green peas, potatoes, sweet corn. Other - artichokes, asparagus, bell peppers, brussel sprouts, cabbage, cauliflower, celery, cucumbers, eggplant, garlic, lettuce (head), okra, onions, radishes, snap beans, tomatoes, misc. vegetables. Fruits: Tree Fruits - Apples, cherries, figs, peaches, pears, plums. Grapes. Berries - Blackberries, blueberries, cranberries, raspberries, strawberries. Melons - Cantaloupe, honeydew, watermelon. Statistics in graph taken from: Ackerman, K et al. 2012|
Land Area to Cultivate Average Crop Yield: Figure 2 compares how much land is required to cultivate each crop between conventional practices and the GROW Biointensive method. The land area needed for each crop is significantly less for the Biointensive method, except for with melons. Dark green and orange vegetables, as well as grapes and berries all require less than 10,000 acres for their average crop yields, while dry beans and peas, starchy and other vegetables needed around 35,000 acres (Ackerman et al. 2012). These statistics are based on the average crop yield produced, and would not be on as large of a scale in urban agriculture.
|Figure 2: Estimated acres needed to cultivate an average crop yield based on methods. Specific crops for each crop type can be found in Figure 1. Statistics in graph taken from: Ackerman, K et al. 2012|
Costs: Low startup and operating costs keep the expenses of farming down. An example can be seen in the 1.5 acre mini-farm named Les Jardins de LaGrelinette in Quebec, Canada. This farm uses GROW Biointensive methods and raised beds. Startup costs were $39,000. Operations costs were minimal, as there are less mechanism and machinery costs. Another reason for lower operation costs is the lack of a need for extra workers, which usually comprise 50% of production costs. Total production can generate $60,000 to $100,000 per acre, which creates a 40% profit margin (Permaculture Apprentice, 2017). A $39,000 startup cost for 1.5 acres is equivalent to less than $3,000 for a 4,000 ft2 farm. Jeavons claims that a net profit of $20,000 to $40,000 can be made off of a mini-farm of this size. The Quebecois farm is a great example that demonstrates the efficacy of the GROW Biointensive method, as it successfully reduced the financial and labor burdens of their farm, which in turn made the farm more profitable.
- Mini-greenhouses require basic tools and are long-lasting. Units are typically around 50 ft2. A unit that lasts 10 years only costs $12.50 per year (Jeavons, 2012). A 4,500 ft2 mini-farm can have up to 90 mini-greenhouses, which would total a yearly cost of $1,125.
When administered appropriately, the GROW Biointensive method clearly shows benefits in soil fertility, efficiency in water use, and higher outputs of crops. However, the 60-30-10 ratio of carbon efficient crops, calorie efficient crops, and vegetables must be strictly adhered to. The 60% is dedicated for grains, and their primary intended use is to replenish the organic carbon stocks of the soil, rather than provide for consumption. Calorie efficient crops that create high yields without needing high quantities of land are shown in Figure 1, such as artichokes, sweet potatoes and squash. The 10% represents any additional vegetable crops. Based on average yield compared to land area required, dark green vegetables, such as broccoli, collard greens and spinach, represent the greatest potential for maximizing healthy food availability, especially relative to input costs. Berries and grapes are also effective for producing high yields. Companion crops can aid in enhanced yields, for example, growing strawberries in tandem with spinach enhances the productivity of the latter (Jeans, 2012).
Issues other than maintaining the aforementioned 60-30-10 ratio include poor relatability of the GROW Biointensive research, as it was based in California, which experiences year-round optimal climates for agriculture. The use of mini-greenhouses can help alleviate this problem. This creates a controlled environment with relatively straightforward set-up, and is cheaper than constructing and maintaining a large-scale commercial greenhouse.
To implement the mini-greenhouses that can utilize the GROW Biointensive method into its soil and associated crop production, an ideal location must be decided upon, taking into consideration land availability and avoiding issues of contamination. Rooftops can elude the ground-level pollutants and topographic restrictions there, and provide an optimal space for constructing a mini-greenhouse. The GROW Biointensive method produces a 4500 ft2 mini-farm, which is optimal for the real-estate related constraints on rooftops. The mini-greenhouses are relatively cheap to produce and uphold, with an estimated cost of $1,125 per year, and each unit only comprises about 50 ft2, forming an adaptable locale. These values are attainable compared to existing rooftop locales, as the Eagle Street Rooftop Farm successfully utilizes 6,000 ft2 of space for vegetable production (Ackerman et al., 2012). In cities with lower building density and higher quantities of vacant lots, the greenhouses can be constructed on the ground, but this is reliant on proper soil conditions.
With increases in vegetable output directly produced in urban locales, there is great potential for increasing the overall vegetable intake of urban consumers. To improve accessibility to vegetables, the UA farms can unite with community supported agriculture (CSA) organizations or infiltrate farmer’s markets in underserved areas. Without the high costs of delivering vegetables from outside sources, the rooftop-grown crops can be kept at a lower price, increasing access to low-income urban populations. Additionally, CSAs, farmer’s markets, and potential partnerships with bodegas and supermarkets provides a revenue stream for the farmers themselves. Although there will be inevitable difficulties in achieving distribution and proper storage for retail, the potential alleviation in urban food security is immense.
Once the research and data on effective UA methods is determined, and the associated costs and distribution practices are established, the decision on private or public ownership of the farms must be made. Government subsidies could help incentivize individuals or co-ops comprised of tenants of the building being used to implement UA into their property. Policies must be created with food security interventions in mind, helping at-risk low-income populations obtain higher vegetables. Further research on how alternative UA methods, such as hydroponics, is necessary, as well as more analysis of ideal policies to promote the combination of mini-greenhouses with the GROW Biointensive method.
Our research focused on the implementation of the GROW Biointensive method for growing crops in UA. We did not incorporate a wide range of comparable methods for crop growth in UA instead of or in tandem with the methods. In the future, we would examine the benefits of hydroponics or vertical farming in UA, as well as look into other soil building practices. Our cost-analysis showed the potential low costs of implementing our combination of the GROW Biointensive method and mini-greenhouses, but a further comparison with both full size greenhouses and conventional growing methods would strengthen our argument. Furthermore, their are valid concerns of adaptability of the results of Jeavons' study on the GROW Bionintensive method to other climates, as his research was done in California. While we tried to adjust for this by advocating for greenhouse use, additional research on the effectiveness of these greenhouses in mitigating the climate differences is necessary. Lastly, our analysis was done for general metropolitan areas. Different cities have different land and resource availability, as well as different needs for its urban residents. Each city will need to modify our outlined plan to best suit their specific area and population.
Implementation of the GROW Biointensive method in tandem with mini-greenhouses on urban rooftops provides a cost and input effective source for urban agriculture based vegetable production. The most productive fruits and vegetables, based on yield per acre, should be concentrated on, bringing dark green and orange vegetable, and berry and grape production into the forefront. To improve food security in urban areas, the UA produced vegetables should be distributed to CSAs or local farmer’s markets, providing an opportunity for improved vegetable intake for an underserved population. Improved healthy food access in cities will directly enhance the intake of fruits and vegetables, which will alleviate malnutrition concerns and enhance overall diets and food security. Policies for UA should be created with food security promotion in mind, with incentives for implanting UA on unused rooftops and vacant lots, particularly catered towards the use of GROW Biointensive and mini-greenhouses. Our next step will involve trials in metropolitan areas across the United States to test the efficacy of our methods. Through these trials, we hope to receive accurate findings that will demonstrate whether or not this combination of the GROW Biointensive method and mini-greenhouses can be successfully implemented in a multitude of urban settings. In addition, we will need to discuss how to implement and fund this UA operation with city officials, who are most knowledgable on their cities and constituents. Through this, we can take our general findings and specify them to each urban area.
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