Urban horticulture as solution for providing
food security in Africa’s largest city: Lagos
Final report Interdisciplinarity Project
Figure 1: Urban agriculture practices (http://www.fao.org/urban-agriculture/en/).
Cilia Dijkman 11309075
Anne Hids 10766200
Ties Delen 10817034
Interdisciplinary Project 2019 Future Planet Studies
Abstract
Lagos is currently the largest city in Sub-Saharan Africa which poses problems in terms of food security making it harder to provide food from rural areas into the city. The population has grown so fast that the food production and distribution from rural areas is not able to compete with the demands from the population of Lagos, thus inside sources of food are required. As a solution for the increasing food insecurity for the growing population of Lagos, urban horticulture is implemented. Currently urban horticulture is already practiced in the form of home gardening with as purpose providing food for the farmers households. Our report focuses on improving urban horticulture in the city of Lagos on the basis of four criteria; Food security, Sustainability, Soil quality and Finance. By constructing an interdisciplinary framework which integrates knowledge from a biological, earth science and business perspective into a matrix there is decides which sustainable practices would be most efficient to implement in urban horticulture in Lagos. It is anticipated that by improving urban horticulture, by switching to sustainable practices, food insecurity could be reduced in Lagos.
Abstract 2 Introduction 4 Theoretical Framework 6 Food security 6 Urban Horticulture 8 Soil degradation 9 Sustainability 11 Microfinance 12
Research Problem and Questions 13
Interdisciplinary integration 14
Selected Methods and Data 14
Results 15
Conclusion 21
Discussion 21
Data Management Table 22
References 24
1. Introduction
In terms of population, Nigeria is currently the largest country in Africa with an estimated population of around 250 million people and an estimated population growth rate of 2.7% (Nwogo & Okoro, 2017). Of these 250 million people, 50.3% live in urban areas. In these urban areas the population growth rate is almost twice as high (4.6%) than for the entire country (UN, 2018). Lagos is by far the biggest metropolitan area with an estimated population of around 21 million people, and an estimated population density of 6871 residents per square kilometer (WordPopulationReview, 2018). The city has seen a doubling of its population over the last 15 years, and researchers expect that its population will double once more by 2050, making it the largest and one of the fastest growing cities of the African continent (WorldPopulationReview, 2018).
With such an increasingly large population, it is a major challenge to ensure food security for all of the inhabitants. Titus & Adetokunbo (2007) estimated that about 39% of the population of Lagos did not have food security, which was expected to get worse. This growing trend of food insecurity does not only have individual consequences, but affects society as a whole. As declared by the Food and Agriculture Organization of the United Nations: “A chronically undernourished person has diminished physical and cognitive abilities, leading to decreased productivity. A society of
undernourished people cannot progress” (FAO, 2000). Thus, when perceived from this point of view, food insecurity is both a consequence of poverty as well as the root cause of it, making it one of the most important primary issues to be solved.
One potential solution for this growing food insecurity problem could be the implementation of large scale urban and peri-urban horticulture, in which urban competition among land use is combined with the production of a vast range of vegetables. Basically, urban horticulture includes ‘all horticultural crops grown for human consumption and ornamental use within and in the immediate surroundings of cities’ (Tixier & de Bon, 2006). By engaging in these horticultural practices, food insecurity can be reduced in multiple ways. First off, urban horticulture, when performed sustainably, increases control over food supplies and independency. This causes economic incentives by means of selling
horticultural surpluses, which in turn reduces food insecurity as well as creates market, thus reducing the overall poverty (Tixier & de Bon, 2006). Furthermore, the metropolitan area of Lagos shows itself to be very suitable for urban horticultural practices, with an estimated potential area suitable for such practices of 4400 ha (Thomas, 2012). However, despite this known potential, 91.6% of urban farmers in Lagos admit not receiving any form of political funding (Lawal & Aliu, 2011), meaning that the farmers are basically left on their own resulting in problems such as insufficient use of fertilizers, soil degradation and the lacking of access to proper irrigation systems.
1.1 Objectives
Despite its potential, the setting up of large scale urban-horticultural practices in Lagos is far from straightforward. This can mostly be ascribed to the fact that it can be perceived as being a complex endeavor, in which differing disciplines (e.g. political, natural sciences, economical) are assessing the problem from differing viewpoints. From a political point of view, for example, one may assess the implication of urban-horticulture in Lagos by comparing it with Nigeria’s current political structure (e.g. subsidies). However, the ‘solutions’ derived from this viewpoint do not take into account the implications perceived from other viewpoints (e.g. biology and the proper use of fertilizers), and vice versa. Therefore, an interdisciplinary approach is needed in which all the relevant disciplines with their different viewpoints are treated as being one inseparable set of variables, providing the basis from which sound and long term solutions could be derived.
In the case of the large scale implementation of urban-horticulture in Lagos, the relevant disciplines are earth-science, biology and business administration. The political viewpoint is neglected, due to the fact that Nigeria’s policies are hard to forecast with its shifting corrupt regime (mostly led by oil prices). Therefore, the relevant basis lies more on the commencement of sustainable agricultural practices (biology and earth science), and how to finance such practices (business
administration). Thus, with biology focusing on the applicability of certain crops in the area, earth science focusing on the sustainable use of soils and irrigation techniques and business administration focusing on opportunities within the economic system which could provide viable financial solutions, these three disciplines supplement one another in acquiring long term solutions. Therefore, the overarching research question is as follows:
How can urban horticulture in Lagos, Nigeria, be improved sustainably to provide more food-security for its inhabitants?
This main research question will be subdivided into three sub-questions which are linked to the relevant disciplines, namely:
- What do the current soil management practices of farmers look like, and how can they be improved?.
- Which crops will contribute most to food security, and in what way can they be most sustainably produced?
- To what extent can microfinance significantly enhance the process of the creation of a fair level playing field, from which urban horticulture could develop itself in Lagos, Nigeria?
Together, these sub-questions provide the interdisciplinary basis from which viable solutions for the setting up of horticultural practices in Lagos can be found. Furthermore, the relevant concepts related to these sub-questions will be explained.
Eventually, the main objective of this research is to provide a matrix in which the different concepts linked to the different disciplines will be assessed against one another. These concepts are food security, sustainability, soil quality and microfinance. Food security is an essential concept due to the fact that it is the ultimate goal that urban-horticultural practices are attempting to achieve. Sustainability is also very relevant due to the circumstance that horticultural practices would decrease food insecurity in the short run, but if not performed sustainably, it could eventually worsen the problem (e.g. soil degradation). This directly highlights the importance of soil quality, which is vital to the growth of crops. Good measures have to be undertaken in order to not degrade the quality of soils, and therefore it is important to understand the long term effects of certain activities. Lastly, microfinance is a very relevant and encompassing concept. It emphasizes the importance of clear financing structures, through which sustainable horticultural practices could be achieved.
Furthermore, from this financial point of view, potential different agricultural practices could be assessed based on their financial applicability.
Thus, based on these concepts, and visualized through the matrix, different agricultural activities are evaluated in the results and the best activities are recommended in the conclusion. These recommendations are meant for potential investors which could help start up and grow the
horticultural practices in the area by means of financing. Thus, the recommendations provides insight for potential investors as to which agricultural activities they should invest in.
2. Theoretical Framework
In order to understand this interdisciplinary research, there are a few key concepts that need further explanation. The theoretical framework of this study consists of five concepts of which four are the criteria used in the matrix. A deeper explanation of the four criteria: food security, sustainability, soil degradation/quality and finance, is given to understand the importance. The fifth concept of Urban Horticulture is also elaborated because with this research the aim is to improve this concept.
2.1 Food security
Food security is the main concept underlying the problem of this research, since ensuring more food security for the inhabitants of Lagos is the goal. The FAO (2010/2011) defines food security as follows:
“Food security exists when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food which meets their dietary needs and food preferences for an active and healthy life.”
Food security is a complicated problem. In an attempt to conceptualize this, the FAO (2008) divided this theory into four dimensions. The first dimension identified by the FAO is physical availability of food. This addresses problems of food production and stock levels (FAO, 2008). Sufficient intake of macronutrients (protein, fat and carbohydrates) resulted in short and unhealthy lives for the largest part of human history. From the beginning of the 18th century however, more and more countries had improved agricultural practices, solving most of the supply problems (Barrett, 2010). The availability of food is relatively easy to measure: just measure food production, and compare this to the amount of inhabitants in an area (while taking into account the recommended intake of calories, fats and
protein).
The second dimension is the economic and physical access to food. This involves food distribution, market prices and expenditure (FAO, 2008). The first dimension alone is not enough to ensure food security. There being enough food for everyone, does not mean everyone has enough food to eat. Access to food adresses the demand side of the food insecurity problems. This is difficult to measure, since economic and physical access to food is heavily dependent on fluctuating aspects such as spiking food prices, sudden loss of resources or unemployment (Barret, 2010). When measuring this dimension, a multidimensional approach should be used because the political, social and economic dimensions are involved.
The third dimension is food utilization. Food utilization includes the nutritional value of the food, sufficient energy intake, diversity of the diet and food distribution within households (FAO, 2008). It also involves if people make good use of the food which they have access to, by choosing healthy foods instead of unhealthy foods. Moreover it includes whether the food is properly prepared, and if it is prepared in a hygienic environment. When the food utilization dimension is not fulfilled, it could lead to micronutrient deficiencies (Barrett, 2010). This is also a tool to measure food utilization.
In this research, the focus will primarily lie on the first three dimensions. They will be discussed from different disciplines: the availability dimension from an Earth scientific and a
biological perspective, the economic and physical access dimension from an economical and business perspective, and the food utilization dimension from a biological perspective. By further exploring these dimensions of food security from different perspectives, it will become clear how these different disciplines are linked to each other.
Food security in Sub-Saharan Africa
According to the FAO (2017), 23.2 % of the population in Sub-Saharan Africa is undernourished. Worldwide, this number was 10.9 in 2017. This number indicates a high amount of households that deal with food insecurity. This means that this is a serious problem, also in Lagos. Titus et al. (2007) researched this problem in Lagos, and came to the conclusion that 39% of the households struggle with food insecurity. This food insecurity is caused by lacking of the four pillars in SSA of food security. The first, food availability, is determined by the amount of food produced and distributed making Lagos as the biggest city in Africa a difficult case to reach food availability. Access to food is determined by economic and physical access, due to a high percentage of poverty in SSA the
economic access of food is low in Lagos. The reach food utilization diets of the inhabitants should be diverse and consists of enough calories. The focus of urban agriculture should be on easily perishable vegetables and and not on staple crops who can more easily be stored and transported from rural areas (Armar-Klemesu, 2000).In SSA the fourth pillar: stability, is hard to establish due to a high degree of exposure to risk influencing production and price. These risks consist of climate conditions such as droughts, natural disasters but also epidemics or political conflicts (FAO, 2017). Many factors, like a stable political and economical environment, determine food security and its stability making it an complex problem.
2.2 Urban Horticulture
Worldwide cities continue to grow, especially in developing countries, which leads to an increasing demand for space and food. The current unsustainable urbanization must change into a healthier and greener one, for which urban horticulture could function as a driver (Thomas, 2012). Urban
horticulture is a small-scale form of urban agriculture which focuses on the cultivation of plants. It uses available land in cities making them economically beneficial by providing food and job opportunities whilst increasing environmental greening (Abegunde, 2012). A research done by Thomas, G., (2012) recognized two production systems in horticulture in sub-Saharan Africa: market gardening, selling the produced goods, and home gardening used for household consumption. Market gardening is performed on a commercial scale contributing to the economy which could help prevent poverty thus being preferred over home gardening. However, market gardening has not reached its full potential yet due to lack of central regulation, economic support and recognition of the
government (Thomas, 2012). This results in lack of information which causes overuse of pesticides, polluted water and competition over suitable arable land. Overuse of pesticides on crops will cause runoff in waters contaminating the environment causing harm to animals and humans. Water is not only polluted by pesticides but also through using fertilizers, which contain too much nutrients, or sewage both running off in rivers. Sometimes these waters are reused by farmers to irrigate their crops and these substances will have an influence on the quality and quantity of the cultivated food.
Especially for the poorest and most vulnerable part of the population, urban agriculture will contribute to more food security and preventing malnutrition (Ojo et al., 2011). Malnutrition arises if a diet is not diverse enough and the person’s intake only consists of certain nutrients lacking others. Implementing diverse dietaries by intercropping different vegetables and fruits prevent malnutrition. Currently leafy vegetables are cultivated more than fruits in the Lagos area and are therefore the most efficient crops to be the focus of improvement (Ojo et al., 2011). Studied by is Ezedinma (1999) that the crops cassava, maize, yams, plantain and banana are cultivated in rural areas and due to
overlapping growing season and competition should be avoided in urban agriculture if grown for economical purposes.
Urban horticulture in Sub-Saharan Africa
Implementing urban horticulture in Lagos will provide: food and nutrition security, sustainable livelihoods, a safe and clean environment, Good governance and a healthy community (Thomas, 2012). Practicing urban horticulture is done in many ways but this research will focus on the six practices currently used in SSA; drip irrigation, fertilizers, water harvesting, agroforestry, IPM, crop rotation and intercropping. These practices are all sustainable and will be further evaluated on their ability to provide food security, financially feasible and good soil quality. This evaluation will take place through interdisciplinary integration in the results, eventually providing a matrix considering all the pro’s and con’s.
2.3 Soil degradation
Soils are a very important ecosystem service, enabling humans to grow food. Soils however, are also very complex bodies in which many different factors can play a role, such as air, organic matter, water and mineral solids (Brady & Weil, 2002). Soil quality is also in direct relation with water quality, water movement, vegetation and land use (Seifu & Elias, 2018). This, however is not taken into account by all farmers. There are many different kinds of soil degradation, and some examples are water erosion, wind erosion, salinization, fertility decline, soil acidification, structure decline and soil contamination (NSW Government, 2018). The causes for soil degradation mostly lie in the lack of information farmers have on agriculture and soil preservation. This allows soil degradation to for example happen in the form of irrigating too much or too little or planting to many crops close together (Ojo et al., 2011). Soil degradation can be a very serious problem, affecting many lives. The restoration of a degraded soil depends on the soils resilience. If the soil degradation is severe and the resilience of the soil is low, the soil degradation can be permanent (Lal, 2001). This means the soil might not be useable for agriculture anymore.
Soil degradation in Sub-Saharan africa
Understanding soil degradation is key to understanding many agricultural issues, since it can have large effects on crop quantity and quality. The most occurring types of soil degradation in
Sub-Saharan Africa are nutrient depletion, soil erosion, increased salinization, soil compaction and acidity (Zelleke et al., 2010). Although all of these forms of soil degradation are occurring in Nigeria, there are two human induced forms that pose the most problems: nutrient depletion and increased salinization (Adediran et al., 2005, Thomas and Middleton, 1993).
Nutrient depletion
Nutrient depletion is often caused by intensive farming, which is done with the intention to increase yields. When agricultural land is farmed intensively, crops deplete the soils organic matter and nutrients (Adediran et al., 2005). In an attempt to provide enough nutrients for the crops on the depleted soils, most farmers use inorganic NPK fertilizers. Even though these fertilizers supply the plants with nitrogen, phosphorus and potassium, these are not sufficient nutrients for the crops. Some essential micronutrients such as boron, zinc and copper are missing (Tandon, 1992). This results in nutrient depletion in the long term.
Effect of missing micronutrients
The most important micronutrients for humans are zinc, iron, copper, boron, manganese, nickel, cobalt, molybdenum and selenium (Knez and Graham, 2012). Plants can, unlike animals, create molecules. They do however require minerals in order to be able to create them. When these
molecules are present in a plant, this plant can be eaten by humans or animals and the molecules can be used in their bodies. When these minerals are lacking from the soil however, the plants cannot make the molecules, and thus they cannot be taken up by the animals or humans that eat them. In the long term, this can cause severe nutrient deficiencies (Knez and Graham, 2012). According to the WHO (2012), more than 2 billion people worldwide suffer from one or two micronutrient
deficiencies. This is a threat for the food security of these people.
Increased salinization
Increased salinization in agricultural occurs when land is over-irrigated, and the evaporation rate is much higher than the infiltration rate. Since the evaporation rates in Sub-Saharan Africa are very high, this is a common problem in the entire area. Increased salinization is a serious problem that can result in decreasing yields and land loss (Thomas and Middleton, 1993). The problem of human induced increased salinization could perhaps be countered by adopting better irrigation practices.
2.4 Sustainability
The concept of sustainability is widely used in different contexts making it difficult to define the term. The most frequently cited definition for sustainability was first mentioned in the Brundtland Report in 1987: “Sustainable development is development that meets the needs of the present without
compromising the ability of future generations to meet their own needs” (p. 37). Biologists started using the concept to explain extracting rates of renewable resources without damaging the integrity of ecosystems (Vos, 2007). Afterwards the concept was applied in economics, to describe the
relationship between natural capital and economy, and is later on also integrated in policy making, business and management. The sustainability challenge is analyzed from three perspectives:
economic, social and environmental, in a widely used principle called ‘sustainability triad’. Applying this tool when addressing sustainability provides a better understanding of the interrelationships between the perspectives (Hiller Connell, 2012). However, in this research the social perspective is not discussed, because the three disciplines making up this paper do not cover this subject.
Worldwide population growth puts pressure on food production giving rise to the ‘Green Revolution’ which caused increase of external inputs practicing agriculture. These external inputs, consisting of pesticides, inorganic fertilizer, animal feedstuffs and machinery, substitute for natural processes and resources making them more susceptible (Pretty, 1995). To practice agriculture in a more sustainable manner these external inputs must be reduced in combination with a more efficient use of present internal resources. The study done by Pretty in 1995 implied that definitions of sustainability are time-and-place-specific meaning there should be no specific defined set of technologies, practices or policies established.
Sustainability in Sub-Saharan Africa
In Sub-Saharan Africa (SSA) the challenge is to improve to productivity of rainfed agricultural systems without damaging the environment. Gowing et al. (2008) examined these systems and approached it with the concept of ‘conservation agriculture’ contributing to more sustainable agriculture systems. The FAO (2017) described the concept of conservation agriculture as: “resource-saving agricultural crop production which is based on enhancing natural biological
processes above and below ground”. This research concluded that CA could reduceproduction costs, improved soil conditions and reduced erosion if the conditions are right. However, weed control is not an option in SSA due to poverty and the lack of these resources. In addition, fertility and cover of the soils is also still an issue thus implanting conservation agriculture in SSA remains an uncertainty needing more research on the subject. Sustainability is one of the four criteria used to evaluate the six agricultural practices in this research. With sustainability there will be looked at consequences for the environment for example no use of external inputs or overuse of pollutants affecting water quality.
2.5 Microfinance
Microfinance is ‘the delivery of financial services, including credit, savings, and insurance to the poor’ (McKee, 2008) in order to ‘release financial constraints and help alleviate poverty’
(Christopher, 2010). Microfinance is performed through Microfinance Institutions (MFI’s), which ranges from individual donors to financial institutions such as banks. These MFI’s grant microfinance loans in two distinctive ways, namely income-financed consumer credits (financed by clients’
personal income) and cash-flow-financed microcredits (interest payment is generated out of the business’ cash flow)(Becker, 2010). Either way, microfinance is developed to help reduce the
micro-entrepreneurial poor. Through microfinance, poor people can more sustainably create and run a business, and gain more financial confidence in the informal markets of which they often are a part of (Christopher, 2010).
Over the last decade, the importance of microfinance in the developing world has grown substantially. This is mainly because of the growing worldwide environmental concern, and the role that microfinance could play in reducing its effects. Thus, microfinance nowadays is not only about providing small scale entrepreneurial aid, but also about securing sustainability on the small scale level. Thus, ‘MFI’s in Asia and Africa are partnering up with renewable energy companies and organizations to explore potential collaborations and business models’. Such collaborations have increasingly led to a new kind of micro-financing, namely sustainability microfinance (McKee, 2008). Instead of focusing on the granting of credit in monetary terms, sustainability microfinance focuses on the offering of tools and entrepreneurial aid, in order to help overcome certain start-up barriers and to ensure sustainable long term development (e.g. granting of right farming tools)(McKee, 2008).
Microfinance in Sub-Saharan Africa
In many Sub-Saharan African (SSA) countries, such as Nigeria, a lot of agricultural small and medium enterprises (SME’s) claim to receive insufficient financing due to the perceived risk that many normal financing companies have of these SME’s (SME’s can rarely meet the conditions set by financial institutions)(Christopher, 2010). Also, as said before, 91.6% of urban horticulturists claim to not receive any form of governmental financial aid (Aliu & Lawal, 2011). However, micro-financing initiatives has grown substantially in Nigeria, and 92% of SME’s claim to have access to MFI loans, with 62% claiming that MFI’s have had a high contribution towards sales and marketing activities (Christopher, 2010). Furthermore, through MFI and renewable energy companies’ partnerships, MFI offers great potential in offering long term sustainable growth of urban horticulture (fertilizers, renewable energies etc.). Thus, microfinance is a relevant growing concept linking horticultural SME’s to potential investors, providing potential long term financial solutions.
3. Research Problem and Questions
This research will examine the current implementation and possibilities for improvement of urban horticulture in the city of Lagos, Nigeria. As the city grows, ensuring food security for the whole population becomes more difficult which puts more pressure on urban horticulture. The current horticulture consists of small farming practices who do not consist of the accurate knowledge to cultivate crops in a sustainable manner lacking information and capital. Analyzing the improvements in cultivation of crops on the basis of four criteria: sustainability, food security, soil quality and finance, makes this research into a complex system. An interdisciplinary approach is required where interests from different disciplines are applied in a matrix to come up with a sustainable solution for providing food security in Lagos. Stated below is the main research question consisting all the disciplines:
How can urban horticulture in Lagos, Nigeria be improved sustainably to provide more food security for its inhabitants?
Several sub questions were formed to support the above research question. The sub questions are composed on the basis of the four criteria, likewise as the conceptual framework. The criteria sustainability is not specifically mentioned in one sub question but it is relevant for all the subjects thus integrated in all of the three sub questions .When studying agriculture, the quality of the soil is an important component as it affects the plant growth. Soil quality is greatly influenced by the soil management practices of farmers. These soil management practices are for example use of fertilizers and pesticides. We want to research what fertilizers or pesticides are currently used, and how these impact the soil fertility. This lead to the following sub question:
What do the current soil management practices of farmers look like, and how can they be improved? After studying soil degradation and quality the focus will be on what is cultivated on these soils. The right crops should be cultivated considering the population needs and maintaining diverse diets in the most sustainable manner. Therefore the following sub question focusing on the criteria: food security, is stated:
Which crops will contribute most to food security, and in what way can they be most sustainably produced?
Whilst the above mentioned sub-questions focus mainly on the earth-science and biological related practices of urban horticulture in Lagos, it is important to have a clear understanding of the finance related structures from which such practices could be improved. Therefore, we pose the last subquestion, focussing on the finance criteria:
To what extent can microfinance significantly enhance the process of the creation of a fair level playing field, from which urban horticulture could develop itself in Lagos, Nigeria?
4. Integration of insights
Because of the complexity of the problems surrounding urban horticulture, the subject needs to be researched from different disciplines. Farmers are dependent on many different factors like
appropriate equipment, good soil and water quality or demand of people. Therefore, the in this case, these disciplines are earth science, biology and business. In this research six sustainable practices; drip irrigation, organic and inorganic fertilizers,, agroforestry, IPM, crop rotation and intercropping will be analysed and visualised in a matrix. The practices were selected by reviewing which practices were most commonly recommended in the literature.
These sustainable practices will be studied and compared on the basis of four criteria; sustainability, finance, food security and soil quality, eventually showing the most efficient choices in the matrix. The earth science and biology perspective have some overlap, since plant growth, water and soil quality are integrated processes. These disciplines will mainly evaluate the current problems
surrounding soil quality and food security, eventually. The business expert in this research group will investigate policies surrounding land use and urban agriculture and evaluating practices on the third criteria: finance. At last there is the the fourth criteria: sustainability, which is elaborated in all of the disciplines. First, the current situation in Lagos is studied and later on which practices would be best suited for horticulture in the city to provide food security in a sustainable and financial feasible manner. Because of this goal of creating a matrix containing four different criteria, all disciplines will definitely be needed and integrated with each other to come up with the most efficient ways of improving urban horticulture.
5. Selected Methods and Data
Methodologies
In this research, only secondary data is used. Since this research is focused on the reflection of different agricultural methods, the use of only secondary data sufficed. The use of primary data in the form of an interview or a field trip would be recommended for future researches on the
implementation of the methods in this research. Finally, with the gathered data from the three disciplines an interdisciplinary integration is performed.
Secondary data
The secondary data for this research will mostly be retrieved from academic journals. These will be reliable data sources for our research. Unfortunately there is no abundance of academic papers available on urban horticulture in Lagos, so we will also use data from other countries in Sub-Saharan Africa, and general data on the subject. Also, some data from large organizations such as the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) will be used. Both of these organizations are specialized agencies of the United Nations (UN). The UN is viewed as a reliable resource, because they often release papers and researches written by academics, and on many topics they have the most recent and thus most accurate data.
Interdisciplinary integration
For each of the three disciplines; earth science, biology and business, an individual paper will be constructed to gather secondary data to answer the research question. By constructing an
interdisciplinary framework, the knowledge of these three disciplines will be integrated into a matrix. The data in this matrix is separated on the basis of the relevant disciplines and will later on, in the results, be further elaborated upon and compared. Eventually, by integrating the results, the best practices will be chosen to improve urban horticulture.
6. Results
The aim of this study is to analyze which sustainable agricultural practices would be best to implement and invest in for farmers in Lagos. In the following part an integration of the three disciplines will be conducted to eventually answer the main research question.
How can urban horticulture in Lagos, Nigeria be improved sustainably to provide more food security for its inhabitants?
The practices will be discussed on the basis of the four criteria which will be summarised and
visualised in a matrix. A written summary of each practice is given with pro’s and con’s seen from the perspective of the four criteria. The four criteria represent the disciplines, in the integration process there will be decided which weigh up more than others and a conclusion can be formed.
6.1 Irrigation
Current situation
Sufficient water availability is essential for crop growth. Therefore, good irrigation techniques are
required for the cultivation of crops. In order to be able to understand the need for an improved irrigation method, it is important to explain the current irrigation situation in urban horticulture in Lagos. At the moment, irrigation in Nigeria is mostly done by hand at more or less regular intervals. However, the amount of water given to the plant is based on the intuition or experience of the farmer (Ojo et al., 2011). Because this type of irrigation is dependent of the farmers intuition, there is definitely room for improvement. When irrigation is done by hand and intuition of the farmer, the amount of water given could very well not be the optimal amount of water to be given to a crop. Also, the frequency of irrigating the crop is probably not optimal. Also, watering the crops by hand is very labour intensive (Ojo et al., 2011).
In the following alinea, an alternative irrigation technique will be discussed. This technique was presented by multiple sources, such as the journal article by Ojo et al (2011). This method was chosen because of the relatively low costs, and low water usage. This is essential since clean water for irrigation can be a scarce resource in Sub-Saharan Africa. For this reason, the technique will also be compared to surface irrigation systems.
Drip irrigation
The most promising irrigation technique to be used in Nigeria would be the implementation of drip/trickle irrigation systems (Ojo et al., 2011). This is a form of irrigation in which drops of water are slowly dripping directly onto the roots of the plant, either above or below the surface of the soil. The biggest advantage of this type of irrigation is the low water usage. A drip irrigation system uses 35% less water than a surface irrigation system (Maisiri et al., 2005). This means less water needs to be pumped upwards, and thus saves fuel. This is both advantageous for the farmer and for the environment.
Apart from drip irrigation being the most sustainable irrigation method, it also increases crop productivity (Ojo et al., 2011). In 2005, Maisiri et al. researched the difference between surface irrigation systems and low-cost drip irrigation systems. When the crop productivity was analysed, Maisiri et al. found that the fields where surface irrigation systems were used had a 7.8 average ton/Ha yield, while the fields with drip irrigation had an average 8.5 ton/Ha yield. Although this is not a significant difference, drip irrigation could still cause higher yields than surface irrigation.
When small sources of water are used to their full potential through this irrigation technique, yields could increase. This could contribute to solving the food security problem in Sub-Saharan Africa (Van Leeuwen, 2001; Hillel, 2001).
From a microfinance point of view, surface irrigation would be quite irrelevant. This is mainly because surface irrigation techniques are often designed for large agricultural fields, which requires
vast amounts of water. Thus, when implemented in urban horticultural contexts, the costs (pumping systems, sprinklers) quickly rise as the amount of land treated decreases (Arbat et al., 2013). Therefore, surface irrigation techniques would be hard to finance in an urban horticultural context.
Drip irrigation techniques are more complex, and therefore the start-up costs are higher. Thus, in the context of microfinance, drip irrigation techniques in urban horticultural areas could be
achieved through sustainable microfinance (providing the right pumps, water filters etc.). However still, the start-up costs are high and it would require long term sustainable agricultural management. Thus, drip-irrigation techniques would be suitable in microfinance terms only if the start-up costs can significantly be lowered.
6.2 Integrated Pest Management
Integrated pest management (IPM) is a term widely used since 1960 when the risks and negative impacts on usage of pesticides began to uncover (Kogan, 1998). Discovered was that certain
pesticides used against animals and plants could be harmful for humans and ecology. Many pesticides contain endocrine disrupting chemicals (EDC) that bioaccumulate in vegetables or leach into surfaces water and damage ecosystems (Bornman, 2017). However, pesticides were used and needed on a large scale against fungi, insects and weeds thus a more sustainable use was necessary. Currently, the use of pesticides in agriculture is used less in Sub-Saharan Africa (SSA) than in Europe and Asia, due to lack of local supply and assets of farmers to purchase them (Grzywacz, 2014). Thus, an alternative approach for pest control is needed in SSA and biological pest control also called biological control agents (BCA) could be an option. Biological pest control makes use of local available ecological resources in the form of natural enemies against unwanted pests. By applying this form op pest control concentrations of toxic pollutants in humans and ecosystems can be reduced. Integrated pest management in Sub-Saharan African countries is still far from straightforward due to the lack of local supply and the inability of farmers to purchase them (Grzywacz, 2014). Therefore, microfinance could significantly provide solutions by means of granting credit to farmers (increasing their purchasing abilities), as well as providing the right pesticides (sustainability microfinance). Thus, biological pest control in combination with (sustainability) microfinance would suffice.
6.3 Agroforestry
Agroforestry is a land-use system in which woody-plants interact with agriculture on the same land. Implementing agroforestry provides several ecosystem services; carbon sequestration, biodiversity conservation, soil enrichment and improvement of air and water quality (Jose, 2009). Trees store carbon dioxide, a greenhouse gas, during their growth contributing to a sustainable environment. Also beneficial to the environment is the return of more biodiversity once removed for agricultural
practices. Agroforestry will improve the quality of soil, water and air by filtering water and producing oxygen and nitrogen (Jose, 2009). The soil quality is also improved by the presence of the trees through more nutrient availability. Thus, agroforestry has a positive impact on the soil quality and is sustainable by mitigation greenhouse gas emissions. However, financially agroforestry is one of the more expensive practices because external inputs are needed and crop space is taken away. For food security there are no direct effects but through improved soil and water quality, better circumstances for crops are formed increasing the yield. Up next the two types of fertilizers, organic and inorganic, are elaborated further.
6.4 Fertilizers
NPK Fertilizers (current situation)
NPK fertilizers are inorganic fertilizers that contain nitrogen, phosphorus and potassium. Since these fertilizers are very affordable, these are the most commonly used fertilizers in Sub-Saharan Africa. Although at first the use of these fertilizers result in larger yields, Tandon (1992) found that in the long term, yields decline. This happens because NPK fertilizers do not contain all necessary nutrients for plant growth. The use of NPK fertilizers can cause nutrient depletion (a form of soil degradation), because not all necessary nutrients are replenished (Adediran et al., 2005). Also, if too much fertilizer is applied to the agricultural field, the fertilizer can runoff the land and enter bodies of water. This can result in a negative impact on water life.
Organic Fertilizers
Organic fertilizers such as manure and compost might be more expensive for the farmers to buy, but they contain much more unique essential nutrients than NPK fertilizers. According to Tandon (1992), the organic fertilizers contain micronutrients such as boron, zinc and copper in addition to nitrogen, phosphorus and potassium which is also found in the NPK fertilizers. The downside of organic fertilizers however is that the amount of nutrients in organic fertilizers vary, which makes it harder to apply the right amount of fertilizer to a field. But, organic fertilizers are beneficial for the soil
structure. According to Eneji et al. (1997, 2001) and Olsen et al. (1970) however, the usage of both organic and inorganic fertilizers can result in sustainable high crop yields.
Organic fertilizers are more expensive than inorganic NPK fertilizers. However, the environmental costs incurred due to mismanagement of NPK fertilizers quite often are higher than the costs of the usage of organic fertilizers (Walsh et al., 2012). Thus, microfinance could help by granting credit and altering the ability of farmers to purchase organic fertilizers. Also, because the use of NPK fertilizers
is still straightforward in SSA countries, proper management of such fertilizers should be achieved through sustainability microfinance.
6.5 Crop management
Intercropping
With intercropping farmers grow two or more crops simultaneously on the same field. It is already performed by many farmers in SSA due to the many advantageous it brings along. The greatest benefit of intercropping is the higher yield gained by using crops that have different root structures, height and nutrient requirements (Lithourgidis et al., 2011). There is also less change of food insecurity due to limited effect of diseases being species specific and if one crop fails others can still be successful. It can also have a positive effect on soil fertility when crops like legumes are used which can fixate nitrogen. In some cases farmers refuse to grow numerous crops simultaneously on one field, then intercropping is not an option.
Crop Rotation
Nevertheless, as an alternative for intercropping ‘crop rotation’ can be applied, where different crops are grown in following seasons. This has the same benefits as with intercropping when differing crops are used who do not attract the same diseases. Still, intercropping would be the superior option due to the fact that the presence of differing root systems that need other nutrients provides better usage of these nutrients and available water (Van Schöll, 1998). Aiming for more food security in the city intercropping is also in favor of crop rotation based on the fact that more diverse crops will be available in one season and not one crop changed seasonally.
Both of the above mentioned crop management techniques, intercropping and crop rotation, could be enhanced significantly if proper management techniques would be initiated. Thus, sustainability microfinance could alter the effectiveness of both techniques. Also, the costs of implementing such practices are not very high (Haggar et al., 2003). Thus, from a food security and soil quality
perspective, crop rotation and intercropping both score high. Also, the two practices are feasible for farmers because no external inputs are needed. Due to the fact that the costs are minimal and the practice is very sustainable, non polluting and long term use, it scores high in all the criteria.
7. Conclusion
All of the mentioned sustainable agricultural practices can contribute in improving urban horticulture and food security in SSA. However, some practices are more suited in Lagos than others, favoring intercropping for ensuring different root systems and better utilisation of the essentials for plant growth: water and nutrients. Intercropping has the lowest costs as it only demands growing different crops next to each other. Also biological pest control should be implemented if resources are available, ensuring a sustainable way in which crops and humans are protected against waste water and pesticides containing harmful contaminants. Because pesticide use is still needed for efficient crop protection but in a more sustainable manner, biological pest control functions as a solution.
A low-cost drip irrigation system would be the preferred manner of irrigation since it is affordable and more effective than surface irrigation systems. It saves water and produces higher yields. An important aspect to keep in mind however, is that the drip irrigation systems require clean water. Water that is not clean could clog up the irrigation system. Unfortunately it was not possible to research this specifically for Lagos.
The recommendation is to use both organic and inorganic fertilizers together, because the plants would get a steady supply of NPK, but also receive the important micronutrients. It is proven that this method results in sustainable high crop yields. A side note on this however is that organic fertilizers are more expensive than NPK fertilizers, and it might not be possible for all urban farmers to implement this measure.
8. Discussion
As a result of this research, the best measures for sustainable agricultural improvements were selected. However, these measures were selected only from a literature study. Often, these studies were not carried out in Lagos, or were not used in urban agriculture. In order to make sure the selected practices are beneficial for urban agriculture in Lagos, on site testing of these measures would be recommended. In addition to the mentioned practices in this study there exist more optional practices that could be implemented in Lagos. Innovative practices which are not yet often mentioned in literature should in further research also be compared. Another recommendation for further research is to investigate whether the water quality of the irrigation water in Lagos is high enough to be able to be used for drip irrigation.
9 Data Management Table
21 (Sub-)
Discipline
Theory Concept(s) Assumptions Insight into
problem Biology Sustainable agriculture - Green revolution - Sustainable triad - recycle urban water The green revolution caused a wide use of external inputs which currently undermines the internal inputs of agriculture. With transforming agriculture to be more sustainable applying the sustainable triad is essential. Sustainable agriculture can’t be seen as a model but a process , thus different solutions in time and space.
Biology Urban horticulture - market gardening - malnutrition Malnutrition could be prevented by implementing diverse diets. To switch from house gardening to market gardening poverty could be reduced. Many people in SSA still suffer from malnutrition due to lack of food and nutrients.
Earth science
Soil degradation - nutrient depletion - soil erosion - increased salinization - soil compaction - acidity Bad soil management, stemming from a lack of knowledge on agriculture, is often the source of soil degradation problems. Also climate can play a role, but this cause is harder to counter.
22 Earth
science
Water quality - salinity
- water infiltration rate - specific ion toxicity - corrosion of equipment - excessive nutrients
Water quality can
have a large impact on soil quality. Poor water quality and
mismanagement of water use can result in soil degradation, and reduced harvests.
Food security - physical availability - economic and physical access to food - food utilization - stability of the other three factors
These concepts are all the problems there are regarding food security. If all of these can be fulfilled at the same time, one obtains food security.
Many people in Sub-Saharan Africa struggle to fulfill at least one of the previously mentioned concepts. This results in many households not having food security. Business administrati on Microfinance - microfinance institutions (MFI’s) - granting of credit - sustainability microfinance Microfinance is a new and developing way of granting small-scale credit (either monetary or providing supplies) to poor people in third-world countries. By doing so, certain economic thresholds could be overcome granting more economic equality. By means of (sustainability) microfinance, urban horticulturists in Lagos, Nigeria, can attain economic opportunities from which they could significantly develop themselves.
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