To what extent could Urban Agriculture alleviate the
future pressures on Amsterdam’s food security?
An economic approach
Name: Sabine de Haes Student number: 2546203
1st supervisor: Eveline van Leeuwen
2nd supervisor: Peter Mulder
1 Table of Contents
1. Introduction 2
1.1. Future Food Security 2
1.2. Urban Agriculture 3
2. Methods an conceptual framework 3
3. Identifying the problem 5
3.1. Ecological pressures 5
3.2. Socio-economic pressures 6
3.3. Overall effect on the food security of the Netherlands 7
4. UA in Amsterdam, a case study 8
4.1. Background study 8
4.1.1 The supply side 8
4.1.2. The demand side 9
4.1.3 Current UA in Amsterdam 10 4.2. The Potential of UA 10 4.2.1. Traditional UA 11 4.2.2. Vertical Farming 13 4.2.3. Rooftop farming 14 4.2.4. Total potential of UA 15 5. Discussion 16
6. Conclusion & Recommendation 17
7. List of literature 18
2 1. Introduction
Urban Agriculture (UA) is an upcoming phenomenon in both developed and less developed cities. In Amsterdam, local food initiatives, the Amsterdam municipality, local urban farmers and also urban dwellers, all contribute to more implementation of urban agriculture. Scientific studies on UA have valued UA in diverse ways and more and more reasons are found for cities to focus on implementation of UA. Quality of life and quality of ecosystems in the cities are found to be improved thoroughly by UA (Van Leeuwen, et al., 2010). Traditional UA however requires much space which in cities is scarce, often polluted and expensive. Also, in wealthy cities such as Amsterdam, involved and protected by strong institutional structures, the food security is expected to remain quite stable. The question rises here to what extent urban agriculture would be an economic efficient approach for supplying the future food demand of Amsterdam. This research question is answered by an attempt to answer the following subquestions; how will future food pressures be economically felt in the Netherlands?, what are currently the most efficient UA techniques? and what could be the potential of UA in Amsterdam regarding food production?
1.1. Future Food Security
‘Food security exists when all people, at all times, have physical and economic access to sufficient safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.’ - World Food Summit (1996)
By the end of the 21th century, projections point out that humanity will be turned in an urban species: large cities will become our main habitat (Deelstra & Girardet 2000). The sizes of cities have shown to be able to grow exponential (Deelstra & Girardet, 2000). Today, most European regions exceed a degree of urbanization of 80%. Projections for Western Europe (graph below) rise up to 90% by 2030, with a consequently increasing trendline (Antrop, 2004).The biosphere on the short and long term, will thus be determined majorly by the cities, by their design and their use of ecosystem services. A problem comes to mind when discussing urbanization, climate change and population growth, namely the future challenges for food security. Because of high population densities, cities in Europe require a large amount of space for their food consumption and have a strong global dependence for their food security (Deelstra & Girardet 2000). This global spread of food production causes, amongst others, global air pollution, damage to wildlife habitats due to a varied amount of polluting
characteristics, and stimulates uses of fossil fuels. Indirectly, these effects will all contribute to a declining food system.
Several consequences will be felt by all globalized markets, and thus also by the Netherlands. One main effect caused by the growing food demand, in combination with intergovernmental measures on ecological issues, are price rises and an increased volatility. This increase will eventually force cities to reduce their food imports (Deelstra & Girardet 2000). This projected phenomenon, amongst others, makes regional and local food production an attractive solution for improving the future food security.
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Graph: Evolution of the level of urbanization in the main European regions between 1950 and 2030 (after United Nations Center for Human Settlement, 1996 and United Nations Center for Human Settlement, 2001).
1.2. Urban Agriculture
According to Smit et al. (1995) cities, as observed during world wars, have an enormous potential for growing food. Urban and peri-urban agriculture arise as options to apply to adapt to further effects of climate change, population growth and urbanization. Urban or peri-urban agriculture (from now on: UA) is defined by the FAO as ‘the growing of plants and the raising of animals within and around cities’. The concept of UA inhibits concepts as local food production, urban farming, green infrastructure and vertical farming (Besthorn, 2013). It can be practiced in many ways in different areas in the city, for example on roofs, vacant land, and empty buildings. Reasons for a city to consider UA, besides easy access to food, vary. Many studies have emphasized the benefits to social, ecological and even economic aspects of cities.
According to a report of the Dienst Milieu en Bouwtoezicht et al. (2013) in the Netherlands, the national and local authorities concerning the agricultural sector, are focusing more and more on sustainable production. In Amsterdam for example, currently several green projects that inhibit UA are implemented by the municipality, such as green roofs and green parks where inhabitants can grow their own spices and crops. However, there is still lack of studies focusing on to what extent UA could contribute to our future food system. Three main types of urban agriculture are defined and analysed on their feasibility in this paper: traditional UA, vertical farming and rooftop farming.
2. Methods and Conceptual Framework
To answer the main question, a conceptual framework is created which will eventually lead to
information and data relevant for the decision to approach UA. Two somewhat simplified analyses are essential for recommending the Amsterdam Municipality to increase efforts to implement UA in Amsterdam.
The first analysis is aimed at identifying the problem: what are broadly the main pressures that could be felt by the food system of the Netherlands? The pressures are, on basis of initial literature research, divided into socio-economic pressures, such as population growth and economic pressures, and environmental factors such as climate change, declining fertile soils and peaks of essential resources. The effect of these pressures is expressed in future price effects for the Dutch food consumption, assuming that developed countries and their strong institutional systems and food policies, will not furtherly notice these pressures in the sense that their food safety is endangered. This will lead to an indicator, a certain price increase or volatility, which will afterwards be useful for balancing to what extent UA could be feasible and who knows even essential regarding the future food system.
4 of Statistics (CBS) an overview is made of the current food system of Amsterdam. Figures of demand and supply are necessary for estimating minimal yields of UA. Consequently, this thesis focusses on the potential of UA in Amsterdam regarding vegetable production. Three main types of UA; traditional UA, vertical farming and rooftop farming, are shortly analysed by using other case studies and
comparing them to the state of being in Amsterdam. This state is analysed in the background analysis of Amsterdam, in which information on food production, consumption and currently applied UA is gathered with literature, CBS and desk research. The different UA types are subsequently
characterized by their feasibility. For traditional UA, the quality of the soil is of great importance for success. Thus, an analysis of the soil quality of Amsterdam must be made. Of course, UA cannot be endlessly practiced: especially in Amsterdam there is limited space. So the total area that can be used for UA will also be analysed by GIS. This second analysis will eventually lead to information about the potential efficiency of UA in Amsterdam.
The feasibility of the UA types, balanced with the future food price changes, will form a
recommendation for the municipality of Amsterdam which will contribute to decisions concerning efforts to implement UA.
A multilayered interdisciplinary answer is formed which could contribute to the focus of the current urban planners of Amsterdam to integrate UA.
5 3. Identifying the problem
3.1. Identifying the food problem
With the information illustrated in the next chapters, we can conclude that the consumption of Amsterdam is quite dependent on the world market. Several factors that form main threats on the future food security according to the Food and Agriculture Organization (FAO) are set out in the following subchapters to find out to what extent the future food security of Amsterdam is threatened. 3.1. Ecological pressures
Climate change
The theory of climate change is reinforced by many scientists and research. The burning ember diagram, developed by Leemans for the IPCC in 2001 incorporates five different climate scenario’s based upon a large collection of scientific efforts to predict effects of climate change on ecological and social sectors. In all of the scenario’s, concerns are more or less necessary for future agricultural developments. The last IPCC report in 2014 shows increased risks compared to earlier estimations. This report in combination with estimations of the Organisation for Economic Co-operation and Development (OECD), conclude that average global temperatures will increase 4 to 6 degrees by 2100. Despite mitigation efforts, an overall temperature increase of 1.6 to 2.6 degrees Celsius is expected to occur by 2050 (IPCC, 2014).
Climate change is expected to impact agriculture due to higher temperatures, changes in availability of water and rainfall, availability of land, terrestrial resources and biodiversity. Temperature rises will have some severe consequences on global agricultural yields, quite uneven geographically distributed in different parts of the world (Parry et al., 2001). Integrated assessment models have projected that agriculture in cooler climates will profit of expected climate change effects while warm climates will be affected. Losses will be felt most strongly in arid and sub-humid tropics in South Asia and Africa due to increasing droughts (FAO, 2001). Developing countries can expect a 9 to 21% decrease of
agricultural productivity. In more northern areas such as Central and North Europe, due to the ‘fertilizer effect’ of rising atmospheric carbon, an increase of crop yields is expected in these regions (Hanjra & Qureshi, 2010). Thus industrialized countries will probably face a 6% decrease to an 8% increase of crop productivity (FAO, 2001).
Locally there could be concluded that climate change will not directly have severe impact on the ecological and agricultural circumstances in the Netherlands. Though, increasing weather extremes could be seen as a threat to harvests. Globally, climate change is expected to have severe impact, indicating that mitigation and adaptation efforts are required to coop with future threats on the food security.
Increasing scarcity of essential resources
According to the FAO, three non-renewable resources essential for agriculture are declining and form a future threat to global food production: water, phosphate and oil.
The watercrisis is currently seen as one of the major threats to the global economy. Often for
agricultural ends, water is tapped from waterbasins and consequently used and spilled for agricultural ends. 40% of the water use in Europe comes from outside Europe, even though Europe has enough
6 sources for clean water itself. Often dry countries export their water via foodproducts while wet countries often import this water. This is a problem according to professor Brussaard of the Wageningen University: to overcome further water scarcity, water should be efficiently tappet and usage should be more localized. Waterrich countries should not subtract water from water poor countries (Hanjra & Qureshi, 2010).
The current globalized industrial food system is highly oil-dependent; fuel for farm machinery, production of pesticides, and transportation of commodities. The theory of Peak Oil matches a bell-shaped line to the graph of oil supply: the peak occurs when half of the resource is extracted. The peak is expected to occur in the early decades of this century (Bardi, 2009).
Phosphate is required for fertilizing agricultural fields for sustaining crop yields. Phosphate is exploited from the non-renewable phosphate rock. While the demand is increasing, the quality of remaining phosphate rock decreases and production costs increase, causing a global phosphate production peak that is expected to occur around 2030 (Cordell, 2009). Between 2050 and 2100 the reserves will be totally depleted. Physical and institutional changes are needed to prevent degradation of agricultural yields dependent on phosphorus. Yet, there are still no international organizations or governance structures which focus on future phosphate problems. According to Cordell et al. (2009), as long as this problem is not recognized by authorities, this could contribute to a severe global food crisis.
Declining land availability and soil quality
The current global food demand is supplied with approximately 12% of the total land mass: 1.5 billion ha of cultivated land. According to measurements of the FAO, cropland has been reduced by 13% and pasture by 4%, over the past 50 years. Landscape changes are expected to cause an agricultural production growth decline of 1.5% per year untill 2030 and 0,9% per year until 2050 which will affect the future food security (FAO, 2001).
The ecology of the food system is dependent on soils. However, recent measurements have demonstrated that for the last forty years, the world has lost 500 thousand hectares of agricultural land (Banerjee & Adenaeuer, 2014). Soil losses are expected to increase and will negatively impact the overall global soil fertility. Of the total global land area, 38% is covered by agricultural land and 11% by arable land (Banerjee & Adenaeuer, 2014). Projections up to 2040 by FAOSTAT (2012) show that agricultural land can merely be increased with 2%. Most fertile soils are currently already being cultivated for food production, thus increases in the future must be especially enhanced by increasing crop yields. For this, investments in agricultural research is needed. However a worldwide decline is measured in these investments. Apparently technology and productivity fatigue is increasing and causing decreases of food yields in major food-producing areas.
3.2. Socio-economic pressures
Demographic pressures
Since the last 50 years, the world population has increased from 3 billion to 7 billion and expectations for 2050 are another increase up to 9.1 billion (FAO, 2009). Also, the world is getting wealthier and thus diets change to a more meat (i.e. intensive) based diet and more consumption(Rabbinge & Linneman, 2009). Diets are highly correlated to per capita GDP: an increasing GDP comes with a higher consumption of meat. Global expectations are that the consumption of meat may double between 2000 and 2050 (Steinfield et al., 2006). Affluent diets involve inputs of grain equivalents three times higher than vegetarian diets which are mostly found in currently developing countries (Rabbinge & Linneman, 2009). For example, the consumption of cereals, both for food and animal feed, is expected to rise from 2.1 billion tons today to 3 billion tons by 2050 (FAO, 2009).
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Economic pressures
Concerns are rising regarding the increasing volatility of food prices. An important trigger for the concern is the food crisis of 2007-08. In this period, the food prices of almost every food item hiked sharply. Ever since, food prices have remained high compared to the beginning of 2000 and an increase is visible in the trendlines, represented in the graph ‘Food price trendlines’ (appendix 1). Several factors are expected to increase, with negative consequences on the future food prices. First of all, an increase in the variability of global food demand is expected. According to Gilbert (2010) food prices are strongly determined by the demand. The increasing globalization of the market and the high speed of economic growth in developing countries such as Asia and India drive commodity price changes. Global imbalances are caused by the continuing fast growth of developing countries in combination with stagnant prospects for developed countries, and are likely to cause more price volatility effects (Gilbert, 2010).
Secondly, a projected increase in the variability of supply shocks, is expected to negatively influence price volatility (Gilbert 2010). This is indirectly caused by climate change discussed above.
Thirdly, lower demand elasticity’s because of the effect of globalization will furtherly diminish barriers of food transmission (Gilbert, 2010). In other words, globalization equalizes local prices to world prices creating less surplus for consumers and a lower demand elasticity.
Higher demands for crops for biofuel are also expected to negatively influence the global food price (Mitchell, 2008).
This all is reinforced by the phenomenon that governments have become to rely more on trade instead of local incentives for protection against potential food risks (Gilbert 2010).
3.3. Overall effect on the food security of the Netherlands
The future value of food in Amsterdam is mainly reliant on global patterns in the food market. This market is influenced by socio-economic and ecological drivers. Important ecological drivers are climate change, scarcity of essential resources such as water, oil and phosphate, and decreasing soil qualities. Temperature rises and more weather extremes will create more risks of failing harvests and thus more fluctuation of food prices. Increasing water scarcity will in the future increase the costs of water and thus the costs of food production. The same effects are caused by other non-renewable sources such as oil and phosphate. Soil degradation is an important issue, less and less fertile soil leads to less space for food production and thus the maximal food capacity of the earth will soon be reached if not invested in increasing yields per area.
These factors are combined in many medium to long-term projection models. In these models prices are generally expected to rise and increase in volatility, due to upward pressures both on the demand and supply side. Without increased investment in new technologies and improved extension, crop productivity will not compensate these pressures.
Since the Netherlands is a rich country with a strong (inter)national institutional system which
provides a high food security, effects are mainly felt in the price changes. The most recently published future scenarios of the FAO all have in common that volatility of prices increases. The slowing
production growth, changing consumption patterns and trends of increasing price spikes all lead to an increasing Food Price Index. Overall, the average increase of world crop prices is expected to increase with 30 to 50 percent over the period 2005-2030 (Msangi et al., 2011). Worldwide, governmental efforts will have to be made to reduce vulnerability to these price changes (Msangi etal., 2011).
8 4. UA in Amsterdam, a case study
4.1. Relevant background information of the case study 4.1.1 The food system of Amsterdam: the supply side
According to research done by the University of Wageningen a large part of the food consumption is designated at production abroad. Approximately 35% of our food is imported. 80% of the fruits we consume and 31% of our vegetables is imported. However, there are possibilities for Amsterdam and Noord-Holland to increase regional food supply.
In the table ‘Grondgebied naar bodemgebruik 2012-2013’ (appendix 2) shared by the Amsterdam Municipality, data is given showing the area in hectares of different landuses in Amsterdam. Relevant data are: Built-up area is 7917,41 hectares (36,1% of the area in Amsterdam). Semi-built-up area, such as graveyards, places for storage and building sites occupy 1341,84 hectares (6,1%). Recreation areas such as parks, gardens, and sport areas make up for 2503,72 hectares (11,4%). For agricultural areas, a division is made between horticulture and remaining area. Horticulture takes in 25,22 hectares (0,1%) and Remaining agricultural area accounts for 2525,93 hectares (11,6%). Forests and natural areas form 498,92 hectares (2,3%).
According to the CBS, Horticulture in Amsterdam signifies area used for growing of crops, under glass and in adjacent waterbasins. The ‘Remaining Agricultural Area’ includes: grass, dikes, sites for
livestock, orchards, agricultural and horticultural area, area used for cultivation of fruits, gardens, grasslands. A percentage of 11,8% would, according to the theory of Martellezo discussed in following subchapters, be enough for feeding the city of Amsterdam. However, the agricultural area does also include dikes, orchards and grasslands. Besides that, the Amsterdam municipality states that the ‘largest fraction’ of the agricultural areas in Amsterdam is characterized by meadow fields. Due to a thick subsoil of peat and past dewatering projects causing subsidence, large parts of these meadow fields are merely suitable for growing grass and grazing of cattle. With this information the value of agricultural areas regarding crop-production declines and it can be stated that more area is needed for meeting food-crop demands of Amsterdam.
To further investigate the true use of agriculture, a study of the Wageningen University is addressed. As can be observed in the table below ‘Production in hectares’, the total number of hectares currently functioning as production for foodcrops is approximately 21 hectares. According to data provided by the University of Wageningen, in Amsterdam currently only potatoes (9 hectares), horticulture vegetables (9 hectares), greenhouse vegetables (2 hectares) and fruits from open ground (1 hectare) are produced on a relevant scale. With a total city surface area of 21900 hectares, this makes the surface area used for agri- and horticulture about 0,1% of the area. By combining information about the yields of potatoes, vegetables and fruits of North-Holland, an estimation can be made about the yields per hectare in Amsterdam (table below ‘Yields in million kilograms’. With a total surface area of 3.449 hectares and a yield of 154,1 million kilogram potatoes, the mean yield per hectare in North-Holland is 44769,51 kilograms of potatoes. In Amsterdam 9 hectares of land is used for growing potatoes, thus the total estimated yield in Amsterdam would be 403.168,6 kilograms. The same calculation for vegetables is used which gives an estimated yield of 47053,3 kilograms per hectare, and a total estimated yield of 517.586,3 kilograms for Amsterdam. For fruitcrops the mean yield in North-Holland is 36188,44 kilograms per hectare. And thus the total estimated yield of Amsterdam for fruit is 36.188,44 kilograms.
9 Production in hectares Amsterdam Noord-Holland Potatoes 9 3.440 Legumes 0 49
Fruit open land 1 934
Vegetables agriculture 0 2.836 Vegetable horticulture 9 5.699 Glassvegetables 2 162 Total 21 13.120
Table: Hectares per production of crops. Source: WUR (2009)
Yields in million kilograms Noord-Holland Nederland Potatoes 154,1 3.501 Eggs 3,8 727,8 Vegetables 401,6 4.444 Legumes 0,3 8 Milk 636,8 12.190 Meat 6,3 670,9 Fruit 33,8 640
Table: Yields in kilograms of North Holland and Holland. Source: WUR (2009)
4.1.2. Food system of Amsterdam: the demand side
This subchapter focusses on the estimated consumption patterns of Amsterdam. Based on research done by CBS and the University of Wageningen a set of relevant data is gathered concerning the food demand of Amsterdam as can be observed in table below containing consumption data. The table shows a total consumption (of drinks and food) of 800 million kilograms per year. The total food consumption (diary produce and drinks excluded) is 268 million kilograms. As the focus of this research lies on suitable crops for production in cities, only these numbers will be discussed. The total number of vegetables consumed per year is 39 million kilograms, fruits account for 35 million
kilograms, 26 million kilograms of potatoes, and 13 million kilogram of grain products. Thus, the total number of crops consumed sums up to 113 million kilograms.
The consumption numbers compared with the supply numbers show us that for potatoes, Amsterdam produces only 1,5% for its own potato demand. Approximately 2% of Amsterdam’s vegetable
consumption is met by Amsterdam’s vegetable production and only 0,1% of the fruit consumption is met by the production in Amsterdam.
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Amsterdam
Total per year (mln/kg)
Per person per year (kg)
Total 800 1042
Drinks (excl.
Dairy) 418 545
Dairy 113 148
Food (excl. dairy) 268 350
Vegetables 39 51
Fruit 35 46
Potatoes 26 34
Grainproducts 13 18
Table: consumption in Amsterdam in kilograms. Source: WUR (2009)
4.2. The potential of UA
Three types of common UA are set out in the following subchapters: traditional UA, vertical farming and rooftopfarming. By addressing case studies, their potential growing crops in Amsterdam is analysed.
4.2.1. Traditional UA
Traditional urban agriculture can be defined as any form of agriculture, intensive or extensive, on the soils of a city. There currently is limited data about the potential of traditional UA practices besides qualitative and anecdotal data. Limited space for UA is a universal feature that impedes the capacity of UA to provide enough food in the cities. A global scale assessment done by Martellozzo analysed a relevant question for this research: the percentage that is needed to meet the vegetable consumption of urban dwellers. Space needed for supplying urban vegetable demands is quantified. The Percentage of urban Area Needed (PAN) was quantified to meet two different targets: to meet the actual
vegetable consumption by urban dwellers and to provide 300 g of vegetables per capita per day to urban dwellers (came from FAO recommendation of minimum daily intake).
PAN is calculated : PAN (i) = 100 x ∑ 𝑔𝑜𝑎𝑙(𝑝𝑟𝑜𝑑)(𝑖,𝑘)max(𝑝𝑟𝑜𝑑)(𝑖,𝑘) 𝑁
𝑘=1 i = country
k = crops (in tonnes)
Assuming that UA would need to produce 300 g/cap/day of vegetable, as can be seen in the map ‘PAN’ (appendix 3) for the Netherlands a percentage of urban area to meet the target is measured of approximately 10%. The question arises: to what extent is this possible? Analysis of available and suitable area in Amsterdam is needed.
The Amsterdam Municipality currently is stimulating implementation of UA. In the map about the current UA in Amsterdam (appendix 4) is demonstrated that Amsterdam has quite a lot of
horticulturegardens (green), several schoolworkgardens (yellow), some gardens for growing spices (purple), some recreational cityfarms (brown), cityfarms (red) and foodcoorperations (blue). When choosing sites for implementation of traditional UA, several procedural aspects have to be taken into notice before action can be taken.
11 the found vacant land. As can be observed in the ‘Bodemkwaliteitskaart’ (appendix 5) soils in
Amsterdam are polluted. The Nota Bodembeheer (2013) shaped a policy framework which functions as structural guide for detecting pollution in soils and creating sound arable land in Amsterdam. The Amsterdam Municipality subsequently distinguished six different zonal areas in Amsterdam depending on the average harmful content of substances in the local soil (appendix 6). Subsequently, they divided the soils into four classes, from clean to polluted; ‘AW2000’(background value), ‘Wonen’ (reside), ‘Industrie’ (industry), and ‘>Industrie’. The order of the zones from 1 to 6 corresponds with the declining quality of the soils. For example, in zone 1 where especially the outer suburbs of Amsterdam are located, the soil layers are most clean and thus most suited for agricultural activity, and is named type AW2000. In the map showing the quality of the soils per zone this is demonstrated. The more centrally located (and older) zones are mostly classed as >industrie. According to the Nota
Bodembeheer (2013) zone 1 and 2 are suited for sound crop growth. This can be seen in table containing the maximum values for pollution (appendix 7) (such as the maximum value of arsene, barium, copper, etc.). Only for the soils classified as AW2000 or ‘Wonen’, the soil is sound enough for growing nature, agriculture and horticulture. With this information, a map can be made via GIS where the vacant land is classified in to land suitable for UA, and land that is unsuitable for UA (GIS map below). Some of the polluted soils are appointed as remediation areas. The ‘Milieu- en
NatuurPlanbureau’ (2007) is currently applying several remediation techniques in these sites to improve the quality of the soil for protection of ecology and health. In the GIS map showing the suitable vacant area for UA these sites are also mapped.
The total surface area that is, or will be after remediation, suitable for UA in Amsterdam sums up to 120,77 hectares of vacant area (of the total 21900 hectares, thus 0,6%). Assuming that this area would be fully embedded to UA, the vacant land in combination with the area that is already utilized for horticulture now, sums up to a total area of more or less 170,99 hectares: 0,8% of the total area of Amsterdam. If assumed that Amsterdam would fully use this space for production of vegetables (vegetables have an estimated yield of 46178,84 kilograms per hectare per year in Amsterdam), Amsterdam would be able to produce about 8.046.000 kilograms of vegetables per year. With a consumption of 39 million kilograms of vegetables per year, this would be good for about 20,6% of the vegetable consumption.
In the center of Amsterdam, soils are currently too polluted for UA. This is due to historic industrial events and dumping of city waste (Nota Bodembeheer, 2015). When crops are grown on polluted soils, the plants take in too much harmful components which could cause health risks when eaten. However, techniques exist for cleaning these soils. An approach which is widely applied today is the promising and cost-effective technology of phytoextraction (Garbisu & Alkorta, 2001). In this practice plants are used to extract, sequester and detoxify pollutants in soils. Via hyperaccumulation above the ground, radionuclide and heavy metal pollutants are quickly taken up by the plants. After this process is accurately applied once, the topsoils are suited for UA (Meagher, 2000).
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Map: vacant land and soil quality in Amsterdam. Source: GIS and the Municipality of Amsterdam
After this information about suitable areas is analysed, another problem occurs, namely, not all the space is directly available for production. According to information provided by the Amsterdam Municipality, housing associations, individuals, project developers or the municipality often own land in cities. The land currently is not sold by the municipality but leased. Leaseholders get property rights, and thus freedom over the land, if the lease is paid. Since the economic crisis however, vacant land sometimes is also offered to citizens or parties with interest with the condition that a creative or sustainable initiative is applied. When the land is owned by a certain party, it is necessary to make an agreement with the owner to be able to interfere with the zoning plan of the specific area.
Sometimes, the process of creating consensus about an agreement can be complex and time drawing. In 2018 the ‘Omgevingswet’ will be implemented and probably create more flexibility on the matter. Overall the costs of UA on the relatively expensive soils of Amsterdam, questions the feasibility of UA compared to agriculture in the countryside where the value of land is more cheap. This is reinforced by the Von Thünen model explained below.
Fact is, there is, besides remediation of soils, no further need for startup costs, making traditional UA a feasible option on this aspect. However for precisely measuring the costs of space in Amsterdam for UA, extensive research of the value of land in Amsterdam is needed too. This can be done by for example the agent-based bilateral residential land market model. In this model land prices in the city are estimated by modeling behavior of buyers and sellers regarding prices of property (Filatova et al., 2009). Though for the ease of this research a more simplified theory is used. Namely the structural validation theory of Von Thünen. The Von Thünen model, was designed for predicting the ideal location of rural development around an isolated urban center. The assumption that the center is isolated, and thus does not exercise trade, is made for the attempt to focus on the fundamental processes which apply for local production. Generalization of complex landuse patterns in and around isolated cities led to discovering laws that govern agricultural prices which are converted to landuse
13 patterns. Von Thünen distinguished four generalized types of economic and agricultural activity as can be seen in the table (appendix 8). The type this paper focusses on is type 2, intensive agriculture. The spatial distribution, as observed in the figure (appendix 9), is according to von Thünen mainly
influenced by three factors: the perishability of the products, a higher economic productivity per land area, and the effort to transport the product. If all these factors are high, the production takes place closest to the city center. This way a cost-efficient optimum is formed for the society in the city (Sasaki & Box, 2003). Type 2 would be most efficient in the first ring around the city center. Space in the city center is best used for economic activity of higher sectors and residential uses (Sasaki & Box, 2003). Thus using land in the city center for agriculture would not be cost-efficient.
4.3.2. Vertical Farming
An alternative farming method, is farming in city skyscrapers. Despite the knowledge of the efficiency of vertical farming, Amsterdam currently does not have any commercial vertical farms. The greatest advantages of vertical farming are that the growing of crops is not dependent on weather, nor seasons, thus they can be produced all year round. Also, limited amount of space is needed due to vertically layered systems. Yields are maximized every harvest period by being able to control optimal ecological circumstances.
Via techniques as aeroponics, hydroponics and drip irrigation, crops can be efficiently grown while barely occupying space. Aoroponics is a technique which does not involve soil: the crops hover in the air and are fed water vapor and nutrients via infusion (Dickson, 2009). Hydroponics does also not include soil, the roots of the plants hang in troughs filled with water with dissolved nutrients. This technique was used quite intensively during World War II, the Allies produced over eight million pounds of vegetables in a limited amount of space. The technique is currently widely used by
indoorfarmers (Dickson, 2009). Drip irrigation is a technique where water is used highly efficiently via tubes which directly feed the stem’s base with the required nutrients. The crops are grown in troughs with fertile material which can be used for years (Dickson, 2009).
Eventhough for this technology more food can be produced with less resources, feasibility still is questionable. Researchers of the Macrothink Institute have investigated the financial and economic feasibility by testing a standard prototype vertical farm construction. The building occupied an area of 0.25 hectares and was about 32 floors high. The multiple stacking created 9.27 hectares of space for the plants to grow. The yields were 516 times higher compared to the yields on 0.25 hectares on open arable land, with no vertical system. In the best and thus least costly scenario high investments for the building and equipment (approximately 201.5 million euro), the costs of producing edible crops would, apart from the investment costs, be around 3.17 euro/kg. These costs depend on building- and
production parameters, production technology, fixed cost and variable cost margin. Technology for production of biomass in vertical farms would have to improve before these costs could decrease (Macrothink Institute, 2014). Due to the high investment costs alone, the feasibility of vertical farming compared to traditional UA and rooftop farming is very high and is not furtherly analysed here. If the vacant land of Amsterdam would be fully used for building vertical farms of 32 floors high, the potential (without involving the costs picture) of vertical farming would be very high. Only 0.25 hectares are needed for creating 9.27 hectares of croparea. One hectare in Amsterdam would thus create about 37,08 hectares. Multiplying this with the amount of vacant land in Amsterdam, would give 37,08*120,77= 4478,15 hectares of arable land. Assuming that Amsterdam only would focus on production of vegetables, the production capacity of Amsterdam could reach absurd high numbers. One hectare could be good for 24.252.000 kilograms of vegetables. For meeting the vegetable consumption of 39 million kg per year, about 1,6 hectare of vertical farms would be enough.
14 (traditional yield on 0,25 hectare: 47000*0,25=11.750 kg and vertical farm yield on 0,25 hectare: 11750*516=6.063.000 kg).
4.3.3. Rooftop farming
Greenroofs, i.e. planted open spaces on top of buildings, can differ from extensive to intensive and with that differ from weight, capital and maintenance costs. The growing of crops can be done either as field crops or in containers (TFPC, 1999). In Amsterdam green roofs are often subsidized and more frequently stimulated (Gemeente Amsterdam, 2014). Green roofs are particularly of interest because of the space it occupies: roofs are not or barely of interest for any other economic or political
activities. This makes it a relatively cheap way of growing crops (Kortright, 2001). A point of concern for implementation is the weight of rooftop farming on buildings which do not incorporate rooftop gardens in their original building plan (Kortright, 2001). Most existing flat roofs are not able to carry intensive green roof technology. In Amsterdam the older buildings, especially in the city center, weight could be an obstacle for implementation. This causes rooftop farming to be limited in options for cropproduction: not every crop can be built on all roofs, needs for soil thickness, water and nutrients can increase heaviness (Whittinghill et al., 2003). Rooftop plants that are more vulnerable to
circumstances outside especially crops that are sensitive for weather extremes or wind, can often not grow efficiently on (high) roofs (Osmundson 1999).
Cityfarmers Amsterdam states that millions of square meters of rooftop surface in Amsterdam are currently not used for rooftop activities, even though they do have potential. German cities where the rooftopsurfaces are comparable with Amsterdam, such as Stuttgart and München, already occupy approximately over a million square meters of rooftopsurface for rooftopgardens which indicates that there is plenty of room for improvement on this field. According to measurements done by the Municipality of Amsterdam, Amsterdam currently uses about 80.000 to 100.000 of square meters for growing plants. This, while Stuttgart, with a similar surface area of 20.756 hectares, already has 1.200.000 square meters (120 hectares) of green on their rooftops (Gemeente Amsterdam, 2014). Several studies on rooftopfarming have concluded that growing conditions do not differ very much from those on the ground. The average yearly yields of rooftop farming measured in different areas in North America with different climate conditions, has devolved to be around 0,45 pounds of vegetables per square foot (Reese, 2014), which in Dutch standards would be approximately 10,7 kilo per square meter. Assuming that Amsterdam would occupy 100 hectares (0,46% of the total surface area) of its rooftopsurface area with crop production, the yield would be about 10,7*1000000= 10.700.000 kg of vegetables per year. With a total vegetable consumption of 39 million kilogram per year in
Amsterdam, rooftop farming on 0,46% surface area in Amsterdam could cover for about 25% percent of this yearly vegetable demand.
Eventhough there is no need for the Von Thunen model here for determining a high value of space in the city, there is an economic barrier related to costs for installation of green roofs. When assumed that the roof is flat and architecturally suited for UA, installation costs of essential tools for crop production are measured to be an average of 30 dollars per square foot, and thus approximately 290 euro per square meter (Reese, 2014).
When installation has occurred, costs could be earned back within some time. According to research done by Brooklyn Grange in California, UA on roofs can have revenue up to 3,59 dollars per square foot. Converting these values to euros and square meters gives a revenue of 3,59/ 0.0929 = 38,64 dollar * 0.912017657 = 35,24 euro per square meter. This indicates that, when the average estimations above are used, and when assumed that no subsidies are dispensed, the costs of installation are earned back within about 8 years.
15 4.3.4. Total potential
With the last analysis of the three different types of UA, several conclusions can be made. By using and comparing the data collected with the different case studies, two summarizing tables can be made. In the first table below this subchapter ‘Estimated potential in Amsterdam’, an overview is made showing the potential of the UA types. Here can be observed that vertical farming, by far, could have the highest selfsufficiency rate and could make Amsterdam an independent vegetable producer. However, when looking at the second table ‘Relative costs’, the relative costs compared to each other can be seen. Here it becomes clear that vertical farming also by far is the most expensive option. Rooftop farming on the other hand, would seem least expensive. Also, the yields of rooftop farming are a little higher than the yields of traditional UA. Making rooftop farming the most feasible option here.
Estimated potential in Amsterdam
(vegetables/year) Traditional UA Vertical farming Rooftop farming
Yield kg/hectare 47.000 24.252.000 107.000
Total Potential Yield 8.000.000 >4 billion 10.700.000 Selfsufficiency
rate* 20,6% >100% 25%
*production potential/vegetable demand of amsterdam
Relative costs
Traditional UA Vertical farming Rooftop farming Upfront capital
costs Medium Very high High
Costs of space Very high Low Low
Production costs Low Very high Medium
Yield per m2 Low Very high Low
16 When identifying the problem, filtering of important factors which could influence the future of food prices was quite problematic. By dividing the pressures into ecological and socio-economic, other important factors, such as future governmental policies, are left out. When estimating future price changes as precisely as possible different scenarios are needed, such as applied by the FAO in many of their reports on future food challenges, but still knowledge gaps cause a rate of uncertainty in
projecting future food prices.
Another important suggestion for possible further research, is to also involve the added value of agriculture in the region of North-Holland. This would probably contribute to a more clear view on the true need for Amsterdam to enlarge its own food production, which would probably be less. To depend less on import (the global market) and more on own food production would probably be economically better approached by enhancing regional food production in the form of traditional agriculture instead of the more costly UA. Vertical farming today would be to expensive compared to traditional agriculture in Noord-Holland. Perhaps it would be a more economic efficient idea to stimulate local food production in Noord-Holland first for decreasing the dependency on the global food market.
Important to notice is that this research purely focusses on the feasibility of UA regarding the
agricultural value. In this case, UA would not make a substantial contribution for Amsterdam to invest in full implementation. An endless number of values; economic values, ecological values, social values, planning values and multidimensional values are linked to urban green areas (Van Leeuwen, et al., 2010). Economic values can be increased by creation of new jobs, but also by making the city a more attractive green setting and creating more options for recreation and leisure (Baycan-Levent et al., 2009). Consequently eventually the value of real estate in the city will considerably benefit of UA (Van Leeuwen et al., 2010).
Ecologically, UA could bring very positive effects or externalities to city life too. For example, the impact of climate change and the heat island effect in the city, is buffered by green. Also, air pollution is counteracted by the absorbing effect of crops and release of oxygen (Baycan-Levent et al., 2009). Phospate and other essential nutrients can be more easily recycled too.
Overall, plenty of positive (external) effects come with UA, increasing the quality of life in the city and thus making UA economically a more realistic practice to implement in cities. This does not
necessarily account for vertical farming though, as the production happens inside. This would mean that vertical farming has less positive effects on the environment compared to traditional UA and rooftop farming.
Furthermore, the analysis focusing on the potential of UA in Amsterdam could only function as indicator for reasons for implementation rather than a cost benefit analysis for implementing the different types of UA. The feasibility was estimated by using other case studies as examples, which of course would not fully correspond with the situation and circumstances in Amsterdam. For example, literature research could not provide exact information about the amount of flat rooftop surfaces in Amsterdam. Hence, a quite similar city, Stuttgart, was used for further analysis of what would be realistic and feasible.
When discussing the thesis, one can conclude that the simplification of several aspects, which was needed for answering the main question without making it too complex and intensive, leaves quite some uncertainty on the true economic feasibility of UA regarding food. However, the research can be seen as motivation for the local or national government to take into account future uncertainties in the food system and securing them by using UA.
17 Whether urban agriculture should be furtherly implemented within the borders of Amsterdam for alleviating future food pressures is a complex question requiring information on future value of food on the one hand and the costs and potential of UA on the other hand. The future value of food in Amsterdam is quite strongly reliant on global patterns in the food market. This market is, amongst others, influenced by socio-economic and ecological drivers. Important ecological drivers are climate change, resource scarcity, soil degradation and the limited capacity of the earth. Temperature rises and more weather extremes will create more risks of failing harvests and thus more fluctuation of food prices. Increasing resource scarcity (especially water, phosphate and crude oil) will in the future increase the costs of these resources and thus the costs of food production. Soil degradation is an important issue, less and less fertile soil leads to less space for food production and thus the maximal food capacity of the earth will be overexploited if not invested in increasing yields per area.
Socio-economic factors which put pressure on our future food security are the demographic fact that the population is expected to grow from 6 billion now to over 9 billion by 2050. Thus the demand wil increase and there can be stated that an increased demand leads to higher prices. More economic effects such as the globalization of China and India’s food market are expected to put pressure on the volatility of global food prices. All this can be felt in the Netherlands in the future especially in the expected increasing volatility and price hikes.
In Amsterdam, interests in UA increase and has been implemented on small scale. Approximately 0,1% of the area of Amsterdam is currently occupied for production of vegetables, potatoes and fruits. The total yield of this cultivated area is good for roughly 1% of the crop consumption of Amsterdam. According to the theory of Martellozzo et al., in Holland, 10% of all the urban area would need to be occupied with agricultural area to meet the vegetable demand of the urban area. Thus, the area of production of Amsterdam needs be increased with approximately 9,9%. If the vacant area in
Amsterdam would be made available for crop growth, Amsterdam would still only be able to reach a total arable area of 0,7%. Several problems concerning the polluted soil would have to be solved with techniques such as phytoextraction. Also, projects would have to be executed increasing the quality of much of the Amsterdam soil which has sank to a certain level in which only meadow fields are able to grow. Thereby, the Von Thünen model demonstrates that production in the city center is more costly than production within the first ring around the city.
There are techniques which depend less on soil and space. Vertical farming is an efficient way of growing crops which requires far less space while yields relatively are very high. Less inputs are needed for higher yields. Though due to high investments in technology this still is a costly option. Rooftop farming is less expensive and can be executed on every flat roof in Amsterdam without requiring space that could otherwise be used for economical practices.
From an economic point of view
An economic advice for the Amsterdam Municipality would be that it is never too early to start anticipating on future food price hikes. Thus, it would be wise to become less reliant of the global market than it currently does. It is not realistic to try to increase yields of crops by investing in the soils of Amsterdam which are of high economic value. This does not imply that the municipality should not invest in traditional agriculture: as discussed in the discussion, a lot of important positive effects emerge with urban green. Regarding food production however, rooftop farming practices would be the most feasible investment. With the lowest spatial costs and a relatively higher yield compared to traditional agriculture, future food price volatility could be buffered by producing food on the roofs of Amsterdam.
18 7. List of Literature
Altieri, M. A., Companioni, N., Cañizares, K., Murphy, C., Rosset, P., Bourque, M., & Nicholls, C. I. (1999). The greening of the “barrios”: urban agriculture for food security in Cuba. Agriculture and Human Values, 16(2), 131-140.
Antrop, M. (2004). Landscape change and the urbanization process in Europe.Landscape and urban
planning, 67(1), 9-26.
Bakker, T. (1984). Horizonten van zelfvoorziening: mogelijkheden voor de voedselvoorziening van
Nederland in autarkische omstandigheden. LEI.
Banerjee, C., & Adenaeuer, L. (2014). Up, up and away! The economics of vertical farming. Journal of
Agricultural Studies, 2(1), 40-60.
Bardi, U. (2009). Peak oil: The four stages of a new idea. Energy, 34(3), 323-326.
Battisti, D. S., & Naylor, R. L. (2009). Historical warnings of future food insecurity with unprecedented seasonal heat. Science, 323(5911), 240-244.
Besthorn, F. H. (2013). Vertical farming: social work and sustainable urban agriculture in an age of global food crises. Australian Social Work, 66(2), 187-203.
City of Amsterdam’s Environmental and Building Department (Dienst Milieu en Bouwtoezicht, or DMB), the Department of Physical Planning (Dienst Ruimtelijke Ordening, or DRO), Waternet and the Waste and Energy Company (Afval Energie Bedrijf, or AEB) (2013) Towards the Amsterdam Circular Economy. Retrieved 1-05-2015 from http://www.amsterdam.nl/gemeente/organisatie/ruimte-
economie/ruimte-duurzaamheid/ruimte-duurzaamheid/making-amsterdam/publications/sustainability-0/towards-the/
Cordell, D., Drangert, J. O., & White, S. (2009). The story of phosphorus: global food security and food for thought. Global environmental change, 19(2), 292-305.
Deelstra, T., & Girardet, H. (2000). Urban agriculture and sustainable cities.Bakker N., Dubbeling M.,
Gündel S., Sabel-Koshella U., de Zeeuw H. Growing cities, growing food. Urban agriculture on the policy agenda. Feldafing, Germany: Zentralstelle für Ernährung und Landwirtschaft (ZEL), 43-66
Filatova, T., Parker, D., & Van der Veen, A. (2009). Agent-based urban land markets: agent's pricing behavior, land prices and urban land use change.Journal of Artificial Societies and Social
Simulation, 12(1), 3.
Garbisu, C., & Alkorta, I. (2001). Phytoextraction: a cost-effective plant-based technology for the removal of metals from the environment. Bioresource technology, 77(3), 229-236.
Gill, S. E., Handley, J. F., Ennos, A. R., & Pauleit, S. (2007). Adapting cities for climate change: the role of the green infrastructure. Built Environment (1978-), 115-133..
Gilbert, C. L., & Morgan, C. W. (2010). Food price volatility. Philosophical Transactions of the Royal
Society of London B: Biological Sciences,365(1554), 3023-3034.
Godfray, H. C. J., Beddington, J. R., Crute, I. R., Haddad, L., Lawrence, D., Muir, J. F., ... & Toulmin, C. (2010). Food security: the challenge of feeding 9 billion people. science, 327(5967), 812-818. Greenbacks from green roofs: forging a new industry in Canada, (Ottawa, Canadian Mortgage and Housing Corporation).
19 Hanjra, M. A., & Qureshi, M. E. (2010). Global water crisis and future food security in an era of climate change. Food Policy, 35(5), 365-377.
Kortright, R. (2001). Evaluating the potential of green roof agriculture. City Farmer. Report on MSc
Thesis available at http://www. cityfarmer. org/greenpotential. html.
Van Leeuwen, E., Nijkamp, P., & de Noronha Vaz, T. (2010). The multifunctional use of urban greenspace. International journal of agricultural sustainability, 8(1-2), 20-25.
Martellozzo, F., Landry, J. S., Plouffe, D., Seufert, V., Rowhani, P., & Ramankutty, N. (2014). Urban agriculture: a global analysis of the space constraint to meet urban vegetable demand. Environmental Research Letters,9(6), 064025.
Meagher, R. B. (2000). Phytoremediation of toxic elemental and organic pollutants. Current opinion in
plant biology, 3(2), 153-162.
Mitchell D. (2008) A note on rising food prices. Policy Research Working Paper 4682. Washington, DC: World Bank, Development Prospects Group.
Msangi, S., Rosegrant, M., & Conforti, P. (2011). World agriculture in a dynamically changing environment: IFPRI's long-term outlook for food and agriculture. Looking ahead in world food and
agriculture: perspectives to 2050, 57-93.
Olesen, J. E., & Bindi, M. (2002). Consequences of climate change for European agricultural productivity, land use and policy. European journal of agronomy, 16(4), 239-262.
Osmundson, T. (1999) Roof gardens: history, design, and construction, (New York, W. W. Norton & Company, Inc.). Peck, Steven, Chris Callaghan, Monica E. Kuhn, and Brad Bass. 1999.
Pinstrup-Andersen, P. (1994). World food trends and future food security.
Rabbinge, R., & Linnemann, A. (2009). European Food Systems in a Changing World. European Science
Foundation. (Rabbinge & Linneman, 2009)
Reese, N. M. (2014). An Assessment of the Potential for Urban Rooftop Agriculture in West Oakland, California.
Trostle, R. (2008). Fluctuating food commodity prices. Amber Waves, 6(5), 11.
Sasaki, Y., & Box, P. (2003). Agent-based verification of von Thünen's location theory. Journal of
Artificial Societies and Social Simulation, 6(2).
TFPC (Toronto Food Policy Council). (1999) Feeding the city from the back forty: a commercial food production plan for the city of Toronto, (Toronto, Toronto Board of Health).
Tscharntke, T., Clough, Y., Wanger, T. C., Jackson, L., Motzke, I., Perfecto, I., ... & Whitbread, A. (2012). Global food security, biodiversity conservation and the future of agricultural intensification. Biological conservation, 151(1), 53-59.
Whitford, V., Ennos, A. R., & Handley, J. F. (2001). “City form and natural process”—indicators for the ecological performance of urban areas and their application to Merseyside, UK. Landscape and urban
20 Whittinghill, L. J., Rowe, D. B., & Cregg, B. M. (2013). Evaluation of vegetable production on extensive green roofs. Agroecology and Sustainable Food Systems, 37(4), 465-484.
Desk research
http://library.wur.nl/WebQuery/wurpubs/463126
http://edepot.wur.nl/14999 www.CBS.nl
21 7. Appendix
1. Graph: Food price trendlines
Graph: Food price trendlines. Source: Trostle, 2008.
22
3.1.1. Grondgebied naar
bodemgebruik, 2012-2013 IN HET ENGELS
2012 2013
bodemgebruik opp. (ha) % opp. (ha) %
verkeersterrein spoorterrein 396.86 1,8 396.55 1,8 wegverkeersterrein 1202.57 5,5 1265.87 5,8 vliegveld 0.64 0,0 0.64 0,0 totaal 1600.06 7,3 1663.05 7,6 bebouwd terrein woonterrein 4529.08 20,6 4528.81 20,6
terrein voor detailhandel,
winkelcentra en horeca 325.11 1,5 318.92 1,5
terrein voor openbare voorzieningen 205.41 0,9 207.93 0,9
terrein voor sociaal-culturele
voorzieningen 529.06 2,4 541.20 2,5 bedrijventerrein 2322.90 10,6 2320.54 10,6 totaal 7911.56 36,1 7917.41 36,1 semi-bebouwd terrein wrakkenopslagplaats 7.30 0,0 7.30 0,0 begraafplaats 124.11 0,6 124.29 0,6 bouwterrein 1254.64 5,7 1158.80 5,3
semi-verhard overig terrein 48.67 0,2 51.46 0,2
totaal 1434.73 6,5 1341.84 6,1 recreatieterrein park en plantsoen 1375.01 6,3 1396.69 6,4 sportterrein 680.87 3,1 681.24 3,1 volkstuin 341.37 1,6 342.46 1,6 dagrecreatief terrein 62.76 0,3 64.23 0,3 verblijfsrecreatief terrein 19.10 0,1 19.10 0,1 totaal 2479.12 11,3 2503.72 11,4 agrarisch terrein
terrein voor glastuinbouw 25.22 0,1 25.22 0,1
overig agrarisch terrein 2525.88 11,5 2525.93 11,5
totaal 2551.1 11,6 2551.15 11,6
bos en natuurlijk terrein
bos 349.18 1,6 328.64 1,5
open droog natuurlijk terrein 73.24 0,3 100.63 0,5
open nat natuurlijk terrein 81.56 0,4 69.65 0,3
totaal 503.97 2,3 498.92 2,3
binnenwater
IJsselmeer/Markermeer 2236.88 10,2 2236.80 10,2
recreatief binnenwater 350.05 1,6 356.51 1,6
overig binnenwater breder dan 6 m. 2865.41 13,1 2863.46 13,1
totaal 5452.34 24,9 5456.77 24,9
totaal-generaal 21932.87 100 21932.87 100
1) Volgens indeling CBS
23 3. map: PAN
24 4. Map: Current UA in Amsterdam
Map: current UA in Amsterdam. Source: Municipality of Amsterdam
5. Map: soil quality
25 6. Table: Soil characteristics per zone
Table: soil characteristics per zone. Source: municipality of Amsterdam
7. Table: Pollution in soils
26 8. Table: Generalization Von Thünen
Table: Generalized agricultural categories in von Thünen's scheme
2. Intensive
Agriculture
Fruits, vegetables, and dairy; products that perish
quickly and must be transported immediately to market.
3. Forestry
Woods, both for construction and firewood. In von
Thünen's time these were the primary sources of energy
and a daily necessity within the city.
4. Grain Farming Grain and staple production.
5. Livestock
Ranching and animal husbandry for meat, hides, and
other non-dairy products.
Table: Generalization Von Thünen. Source: Sasaki & Box, 2003.
9. Illustration: Spatial Distribution Von Thünen
