The use of compost in urban agriculture



Composting of Organic Household Waste

UWEP Working Document 1

Doortje 't Hart

Jacomijn Pluimers


Crabethstraat 38 F, 2801 AN Gouda, the Netherlands

tel: +31 182 522625, fax: +31 182 584885, e-mail: waste@nld.toolnet.org





1.1. Historical background 5

1.2. Problem description 5

1.3. Justification 6

1.3.1. Opportunities of urban agriculture 6

1.3.2. Opportunities of composting 7

1.3.3. Potentials of linking composting and urban agriculture 7

1.4. Central research questions and methodology 8

1.4.1. Literature study 8

1.4.2. Network study 8

1.4.3. Questionnaire 9

1.5. Structure of this report 9


2.1. Definition 11

2.2. Reasons for practising urban agriculture 12

2.3. Who are the urban farmers? 14

2.4. Space used for urban agriculture 16

2.4.1. Availability, quality and ownership of land 16

2.4.2. Other spaces used for urban agriculture 18

2.4.3. Scale of urban agriculture 20

2.5. Types of crops 21

2.6. Crop management practices 23

2.6.1. Optimal use of resources 23

2.6.2. Knowledge and information 24

2.6.3. Protection against pollution 24

2.6.4. Protection against theft 25

2.7. Political context 25

2.8. Major constraints 26


3.1. Urban organic waste 28

3.2. Compost 29

3.2.1. Processes 29

3.2.2. Characteristics of compost 30

3.3. The use of organic waste as fertilizer 32

3.3.1. The use of garbage 33

3.3.2. Compost use 35

3.3.3. Advantages and disadvantages of the use of organic waste 38

3.4. Environmental and health risks 39

3.4.1. Pathogens 39

3.4.2. Heavy metals 39

3.4.3. Toxic organic substances 40


4.1. The organizations 42

4.1.1. The organizations and their objectives 42

4.1.2. The roles of the organizations 45

4.2. Urban agriculture projects 48

4.2.1. Objectives 48

4.2.2. Who are the urban farmers? 51

4.2.3. Space and plot size 53

4.2.4. Crops and crop management 55

4.2.5. Constraints in urban agriculture 56

4.3. The use of compost in urban agriculture projects 57

4.3.1. Reasons for not using compost 57

4.3.2. The use of compost 57

4.3.3. Constraints of using compost 58

4.3.4. Other fertilizers 58

4.3.5. The price of compost per project 60


5.1. Conclusions from the literature study 61

5.2. Conclusions from the questionnaire 63

5.3. Conclusions from the network study 65

5.4. Overall conclusions 65

5.5. Possible follow-up activities 67








Urban agriculture may seem a waste of time and energy, but for many people in the South it forms an important part of their income and/or food. Given this situation and the problem of growing amounts of (organic) waste in cities, we decided to execute an inventory study on the use of compost in urban agriculture.

What was initially a theoretical idea to us, turned out to be a living phenomenon for the people involved. That made this study a challenge to us: we were motivated by the reactions from the South to come up with relevant data and with future plans on the use of compost in urban agriculture. We hope this report will stimulate people working for CBOs, NGOs, governments and research institutes to pay attention to the use of urban compost in urban agriculture.

We would like to thank all the people who contributed in one way or another to this report: the colleagues of WASTE for the pleasant working environment and the support, Jac Smit (UAN), Luc Mougeot (IDRC) and many others for providing useful information, Ann Waters-Bayer (ETC) for the very inspiring discussion we had, Anne-Lies Risseeuw (WASTE) for the language corrections, and Anneke Lubbers and Thea 't Hart for translating the questionnaire. A word of special thanks goes to Inge Lardinois of WASTE, who supported us throughout the whole process with innovative ideas, helpful comments and Easter eggs. Last but not least we would like to thank all the people who responded to the questionnaire for their very thorough and inspiring answers; we are very grateful to them. Our special thanks go to John Y. Musa of AHA (Cameroon), who sent us some very nice pictures of urban agriculture in Bamenda.

Is urban agriculture a wasted agriculture? Looking at the experiences in the field we believe that it is certainly not wasted; on the contrary, it has potentials to turn waste into food and money for urban people in the South.


Gouda, April 1996 Doortje 't Hart

Jacomijn Pluimers




. Historical background

In 1989, WASTE started a research on the potentials of recycling to become a source of income for people in the low-income areas of Nairobi (Kenya) at the request of the Undugu Society of Kenya, an NGO. Rather than `reinvent the wheel' and try to develop recycling activities itself, WASTE decided to involve local consultants from five cities where resource recovery activities are better developed than in Nairobi. Local consultants in Cairo, Bamako, Accra, Manila and Calcutta investigated the technologies used, the products made and the markets covered by micro and small enterprises recovering urban solid waste materials. Ten waste materials were identified: rubber, plastic, motor oil, cooking oil, tin cans, photochemicals, broken glass, bone and horn, household batteries and organic waste. One result was the publication "Organic Waste; options for small-scale resource recovery" (Lardinois & Klundert, 1993), the first book in a series on Urban Solid Waste.

In 1995, WASTE started the so-called Urban Waste Expertise Programme (UWEP), which builds on the results and experiences gained from the WAREN research. One of the activities of the UWEP programme is a research on `composting organic household waste' (UWEP 5). This research aims at documenting successful composting activities and deals specifically with the type and scale of technology used, financial and economic aspects and the marketing and application of compost. Since not much is known about the use of compost in urban agriculture and as a means to broaden the marketing opportunities for compost, an inventory study on this topic was started. This report comprises the results of this inventory study.


. Problem description

In Bamako `the cultivation of cereals is banned since 1989, on the grounds that the tall stalks provide hiding places for bandits' (Lachance, 1993). Other official bans refer to the health risks of keeping livestock in town and the fact that fields of maize would obstruct the view of drivers and cause accidents (Mougeot, 1993). Behind these official stories, lies the fact that urban agriculture does not fit into people's perception of what a city should be.

Whatever official reasons there are to ban urban agriculture, it is impossible to deny its growing importance in the expanding cities of the South. Urban agriculture is practised in many cities, often at a considerable scale. It provides many people with the necessary starch, vitamins and minerals.

All over the world cities are growing because of urban migration and natural growth. The increase of the population is often so fast that the delivery of basic services, such as water supply, sanitation and waste removal cannot keep up. Unemployment, growing poverty and deterioration of the environment are related problems to urban expansion.

With an increasing population and often a more Western way of living, the amounts of waste generated are consequently growing. The municipal waste collection service is usually not capable to deal with this waste problem. In Southern countries waste is removed only in some parts of the city, such as the centre and the high-income areas, in the rest of the city the waste is left along side the streets, in streams and in scattered heaps between the houses. As a result of this and the growing poverty, informal waste recovery activities have arisen. Plastic bags are washed and sold again, oil tins are used for making lamps, tyres for making shoes and organic waste is converted into compost.


. Justification


. Opportunities of urban agriculture

Smit and Nasr (1992) describe that the benefits of urban agriculture vary in time and place. In times of particular stress urban agriculture can be practised as a defence against hunger and malnutrition, at other times it may be practised to improve the quality of the urban environment or the objective lies in between where both income and food supply are of interest to the farmer.

Benefits of urban agriculture for the city can be:

1. Poverty alleviation

2. Food provision/lower food prices

3. Employment

4. Improvement of the quality of the urban environment, through greening and reduction in pollution

5. Strengthened economic base (by reducing the need to import food)

6. Contribution to balancing global ecology (among other things by reducing the need for transportation)

(Smit and Nasr, 1992)

In addition, urban agriculture has a threefold relation with resources:

a. Urban waste can be recycled and used in urban agriculture

b. Some (unused) areas can be made productive by urban agriculture

c. Other resources can be conserved through urban agriculture, because urban agriculture:

- Saves energy (transportation/fuel wood)

- Saves food expenditures, so the available money can be used for non-food expenses

- Can reduce land pressure and thus withhold conversion of deserts, mountain slopes and rainforests into cropland

- Can conserve human resources (rural farming skills)

- Offers opportunities to achieve equity between groups

(Smit and Nasr, 1992)

Alongside the aforementioned potentials, the practice of urban agriculture may however also include risks. Examples of the risks are: health problems by eating contaminated products (air pollution by exhaust gasses and soil contamination) and taking away the market for products from rural areas and thus possibly creating new problems in the rural areas.


. Opportunities of composting

A large part of urban waste in Southern cities is organic and one of the ways of recovering this is through composting. Resource recovery creates employment, reduces the volume of waste to be disposed of by municipal authorities, it saves foreign currency by reducing the quantity of raw materials needed in the production process and it plays a role in natural resource conservation.

Organic waste can be re-used for compost making, raising animals or fish (fodder) and as a source of energy (biogas or briquettes). Composting is a promising activity, because waste is turned into a good soil conditioner which can be used for agricultural practices. An important constraint in compost-making is the lack of a nearby market. Transport of compost to rural areas is expensive and therefore this study looks into the possibilities to use the urban compost in urban agriculture.

Also composting can have risks. We can think of health problems, when the process of composting is not applied accurately; and also when the waste contains hazardous components, such as chemicals or heavy metals which may effect the quality of the compost.


. Potentials of linking composting and urban agriculture

Both urban agriculture and composting seem to be promising activities, which can contribute to solve the complex urban problems.

There are various options for the use of compost, such as agriculture in rural areas or urban areas and urban forestry or `greening the city'. Linking compost with urban agriculture seems to have most potentials, because of low transporting costs and direct benefits to low-income dwellers. This may cause the closure of nutrient cycles, a reduction in transporting costs and the use of fertilizer, available space and labour made more productive and a healthier urban environment.

The concept of closing cycles is not new. An interesting example in this context is that in Berlin, in the early days of this century, farmers who brought their products into the city, had to carry waste back, out of the city.


. Central research questions and methodology

The use of compost in urban agriculture is a rather new concept, a field in which, to date, limited research has been carried out. Because of its potentials, we decided to carry out an inventory study around the following question:

* Can urban agriculture be a potential market for compost, made of urban organic waste materials?


. Literature study

We started the study with an inventory of the literature, mainly available in the Netherlands, on urban agriculture and composting. The sub-questions for this inventory were:

a. What is meant by urban agriculture?

b. What are reasons for people to practise urban agriculture?

c. Who are the urban farmers?

d. Which forms of urban agriculture exist?

e. What are the constraints faced by urban farmers?

f. At which scale is urban agriculture practised?

g. Is compost used in urban agriculture?

h. What are problems of using compost in urban agriculture?


. Network study

Besides gathering information on the subject, also an inventory of resource persons, mainly in the Netherlands, was drawn up. Interviewing these resource persons gave information on the expertise available within several organizations in addition to information on urban agriculture.

The sub-questions that are related to this expertise network were:

i. Who has expertise on urban agriculture and/or compost in the Netherlands?

j. What type of organization are they working for?

k. What type of activities are they undertaking concerning urban agriculture and/or the use of compost in urban agriculture?

The results of this inventory on the `expertise network' can be found in Appendix I.


. Questionnaire

Within the scope of this study field research was not possible. In order to obtain recent field information a questionnaire was elaborated. The central objective of this questionnaire was:

To obtain recent information about the actual occurrence of urban agriculture and the existing potentials and threats of urban agriculture and the use of compost.

Names and addresses of the organizations to whom the questionnaire was sent, were selected during the `network study'. The majority of the organizations that we approached are contacts of WASTE, ETC Foundation, CEBEMO and Both ENDS. Other addresses were found in ILEIA's newsletter of December 1994, Vol 10 no. 4 `Farming at close quarters' and other literature. Appendix II includes the addresses and a short description of the organizations.

The questionnaire was sent to 20 organizations in 16 different countries in Asia, Africa and Latin America, working with urban agriculture. Because it was not known whether these organizations used compost, the questionnaire was kept short and the questions about compost were not very specific. 14 questionnaires were returned!

The questionnaire was subdivided into 3 major parts. Firstly, information was requested on the type of organization, their objectives and their involvement in urban agriculture. Secondly, questions were asked about the type of urban agriculture project; what the goals are, who the farmers are, what type of space is used, which crops are cultivated and what the constraints are the urban farmer faces? Thirdly, it was asked whether or not compost was used in urban agriculture. Appendix III includes a complete print-out of the questionnaire.


. Structure of this report

Chapter 2 describes all the aspects determining the various forms of urban agriculture. The chapter starts with an explanation of the definition of urban agriculture that is used in this report. Furthermore, the different reasons to practise urban agriculture are reviewed and the question `who the urban farmers are' is answered. Section 2.4 contains the important issue of the type of space used for urban agriculture; Section 2.5 presents the types of crops and Section 2.6 reviews the crop management practices. After some comments on the political context in 2.7, Section 2.8 reviews the major constraints.

Chapter 3 presents data on the use of organic waste in urban agriculture. Firstly, the chapter describes urban organic waste and its characteristics. In 3.2 the focus turns to compost. Section 3.3 analyzes the use of organic waste as fertilizer, whereby a distinction is made between fresh garbage and compost. Section 3.4 reviews the environmental and health risks.

Chapter 4 shows the results from the questionnaire. Section 4.1 gives an overview of the organizations who returned the questionnaire. Section 4.2 presents the urban agriculture projects: objectives, target groups and description of the practised type of agriculture. Section 4.3 gives a description of the use of compost in urban agriculture projects.

Chapter 5 presents the major conclusions from this inventory study: 5.1 contains the conclusions based on the literature study, 5.2 the conclusions from the questionnaire, 5.3 the conclusions from the network study. You will find the overall conclusions in Section 5.4, and Section 5.5 describes the possible follow-up activities.

Appendix I presents the results of the network study. In Appendix II lists the names and addresses of the organizations to whom a questionnaire (Appendix III) was sent, and Appendix IV gives an overview of the crops cultivated in urban agriculture.