Agroecology is a dynamic concept that has gained prominence in scientific, 
agricultural and political
discourse in recent years (IAASTD, 2009; IPES-Food, 2016). During its 
historical evolution,
agroecology has expanded beyond the field, farm and agroecosystem scales to 
encompass, over the
last decade, the whole food system. Agroecological approaches explicitly aim at 
transforming food
and agriculture systems, addressing the root causes of problems and providing 
holistic and long-term
solutions (FAO, 2018a) that consider the complexity of farming systems within 
their social, economic
and ecological contexts (Petersen and Arbenz, 2018). Agroecological approaches 
are increasingly
considered as possible alternatives to the industrial model of agricultural 
improvement,14  representing
concrete transition pathways towards SFSs that enhance FSN (De Schutter, 2010; 
HLPE, 2016,

In September 2014, FAO organized an International Symposium on Agroecology for 
FSN, followed in
2015 by three regional meetings in Latin America, Africa and Asia (FAO, 
2015a,b; 2016a), a further
three regional meetings in 2016 in Latin America, China and Europe, and the 
most recent in 2017 in
North Africa (FAO, 2018b). A second International Symposium was convened by FAO 
in April 2018,
the key outcomes of which are documented in Chapter 4 and have informed the 
development of some
of the recommendations in this report.

This chapter begins by describing how the concept of agroecology has emerged 
from constituent
elements of agriculture and ecology to embrace a transdisciplinary science, a 
set of practices and a
social movement. It then presents the definition and development of 
agroecological principles over
time, analysing how these principles contribute to FSN and the achievement of 
the Sustainable
Development Goals (SDGs). Finally, some contested areas in current debates 
around agroecology
and      major knowledge gaps are also highlighted.

1.1  Agroecology: a science, a set of practices and a social

Multiple definitions of agroecology exist as different institutions and 
countries adopt definitions that
reflect their own concerns and priorities. This report aims at defining and 
agroecological approaches for sustainable agriculture and food systems that 
enhance FSN.

Historically, traditional agricultural systems in many parts of the world could 
be considered to be
agroecological. These include traditional agroforestry, incorporation of 
organic material into soils,
mixed cropping systems with livestock and the use of a wide variety of edible 
crops (Altieri, 2004a).
Dynamic local knowledge systems developed complex approaches to managing pests, 
diseases and
ensuring culturally appropriate, nutrient-rich food supplies (Altieri 2004a; 
Oteros-Rozas et al., 2013).
Modern agroecological science, as a response to the social and ecological 
impacts of the so-called
“industrial” agriculture model, draws on many locally derived concepts and 
practices, but is also a
dynamic and active area of scientific research (Migliorini et al., 2018l; 
Montalba et al., 2017;
Vandermeer and Perfecto, 2013).

In its report on sustainable agricultural development and the role of 
livestock, the HLPE (2016b))
described agroecology from a scientific and technical perspective as the 
application of ecological
concepts and principles to farming systems, focusing on the interactions 
between plants, animals,
humans and the environment, to foster sustainable agricultural development in 
order to ensure FSN
for   all, now and in the future. The report acknowledges that “today’s more 
transformative visions of
agroecology integrate transdisciplinary knowledge, farmers’ practices and 
social movements while
recognizing their mutual dependence”, and calls for looking at a broader 
conception of the term.

This is in line with agroecological approaches having broadened in recent 
years, to focus on whole
agrifood systems, not only farming systems (Thompson and Scoones, 2009), and to 
go beyond

¹⁴  The industrial model of agricultural improvement refers to intensive 
agricultural systems, dominated by large-scale
specialized farms, relying in certain cases heavily on fossil fuel and 
purchased, non-renewable and synthetic inputs.
These systems are criticized by agroecology proponents who point to their 
negative social, health and environmental
impacts (IPES-Food, 2016; HLPE, 2016).

separating scientific and technical dimensions of agroecology from the social 
and political dimensions,
by embracing a transdisciplinary outlook.

The notion of agroecology as the application of ecological principles in 
agriculture, while apparently
simple, hides complex realities because ecology and agriculture are dynamic 

Ecology refers to the branch of biology dealing not only with interactions 
among organisms and with
their environment (Tansley, 1935) but also to social movements concerned with 
the protection of the
environment (Sills, 1974). Although ecological science began as a subdivision 
of biology, it has more
recently emerged as an interdisciplinary field with many different branches, 
including political ecology
(Robbins, 2004), many of which link biological, physical and social sciences.

Agriculture is basically the set of practices through which people produce food 
(Spedding, 1996).
Agriculture, as a concept, is also evolving, with increasing awareness that 
agriculture is multi-
functional (Caron et al., 2008; IAASTD, 2009), and that agricultural production 
cannot be separated
from the other aspects of food systems, such as food supply chains, the food 
environment and
consumption (Jones and Street, eds,1990; HLPE, 2017b).

These trends in ecology and agriculture come together in an emerging 
transdisciplinary focus on
understanding and managing coupled social–ecological systems (Berkes and Folke, 
eds,1998) in a
context of growing concerns about human activities, and agriculture in 
particular, leading to planetary
boundaries being exceeded (Steffen et al., 2015; Campbell, 2017). A key reason 
that agroecology is
gaining traction in the discourse on achieving FSN is because it is perceived 
to bridge ecological and
social dimensions associated with the development of resilient food systems in 
the face of climate
change and other global challenges (Caron et al., 2014).

Agroecology is increasingly seen as a transdisciplinary, participatory and 
action-oriented approach
(Méndez et al., 2013; Gliessman, 2018) that embraces three dimensions: a 
transdisciplinary science
(Definition 1), a set of practices and a social movement (Wezel et al., 2009; 
Wezel and Silva,
2017; Agroecology Europe, 2017) (Box 3). These three dimensions of agroecology, 
their articulation
and co-evolution together constitute a holistic approach (e.g. Agroecology 
Europe, 2017; Gliessman,

Box 3      Multiple definitions of agroecology

As a science, agroecology is: (i) the integrative study of the ecology of the 
entire food system,
encompassing ecological, economic and social dimensions or, in brief, the 
ecology of the food system
(Francis       et al., 2003); (ii) the application of ecological concepts and 
principles to the design and
management of sustainable food systems (Gliessman, 2007); and, more recently, 
(iii) the integration of
research, education, action and change that brings sustainability to all parts 
of the food system:
ecological, economic and social (Gliessman, 2018).

Agroecological practices aim at improving agroecosystems by harnessing natural 
processes, creating
beneficial biological interactions and synergies among their components 
(Gliessman, ed, 1990) and
using, in the best way, ecological processes and ecosystem services for the 
development and
implementation of practices (Wezel et al., 2014).

As a social movement, agroecology is seen as a solution to current challenges 
such as climate change
and malnutrition, contrasting with the so-called “industrial” model and 
transforming it to build locally
relevant food systems that strengthen the economic viability of rural areas 
based on short marketing
chains, and fair and safe food production. It supports diverse forms of 
smallholder food production and
family farming, farmers and rural communities, food sovereignty, local 
knowledge, social justice, local
identity and culture, and indigenous rights for seeds and breeds (Altieri and 
Toledo, 2011; Rosset et al.,
2011; Nyéléni, 2015). This dimension of agroecology as a political movement is 
becoming increasingly
prominent (Gonzalez de Molina, 2013; Toledo and Barrera-Bassols, 2017).

Sources: FAO (2017a), Agroecology Europe (2017).

Definition 1    Transdisciplinary science

Transdisciplinary science transcends disciplinary boundaries and seeks to 
generate transformative
outcomes by having:

(i)     a problem focus (research originates from and is contextualized in 
”real-world” problems);

(ii)    an evolving methodology (the research involves iterative, reflective 
processes that are
responsive to the particular questions, settings and research groupings 
involved); and

(iii)   collaboration (including among transdisciplinary researchers, 
disciplinary researchers and
external actors with interests in the research) (Russel et al., 2008).

This has been interpreted in agroecology to involve integration of different 
academic disciplines as
well as diverse forms of knowledge, including experiential, cultural and 
spiritual (Méndez et al., 2015).

Transdisciplinary science differs from ”multidisciplinary” science, where 
people from different
disciplines work together, each drawing on their disciplinary knowledge in an 
additive rather than
integrative way, and from ”interdisciplinary” science, where knowledge and 
methods from different
disciplines are integrated, encompassing a synthesis of approaches but not 
necessarily involving
other stakeholders or focus on generating transformative outcomes (Petrie, 

1.1.1   Agroecology as a science

The term “agroecology” appeared for the first time in the scientific literature 
at the beginning of the
twentieth century to designate the application of ecological methods and 
principles in agricultural
sciences, including zoology, agronomy and crop physiology (Figure 2a) (Bensin, 
1928, 1930;
Friederichs, 1930; Klages, 1942; Gliessman, 1997; Dalgaard et al., 2003; Wezel 
et al., 2009; Wezel
and Soldat, 2009). In the 1950s and 1960s, Tischler published several articles 
on agroecological
research, analysing different components (plants, animals, soils, climate) and 
their interactions, as
well as the impact of human management on them. His book was probably the first 
book entitled
Agroecology (Tischler, 1965).

The concept of an “agroecosystem”, considered as a domesticated, human-managed 
ecosystem, was
introduced by Odum (1969). Two decades later, agroecology began to move beyond 
the field and
farm scales to embrace whole agroecosystems (Altieri, 1987, 1989; Conway, 1987; 
Marten, 1988;
Wezel et al., 2009; Wezel and Soldat, 2009). Important contributions also came 
from Mexican
scientists emphazing intercultural processes for constructing agroecological 
knowledge that combines
ecological science with local peoples’ knowledge (e.g. Hernández Xolocotzi, 

Building on these reflections, Altieri (1995) defined agroecology as “the 
application of ecological
concepts and principles to the design and management of sustainable 
agroecosystems”. FAO (FAO,
2016d) further refined this definition, stating that: “Agroecological 
innovations apply ecological
principles    - such as recycling, resource use efficiency, reducing external 
inputs, diversification,
integration, soil health and synergies -, for the design of farming systems 
that strengthen the
interactions between plants, animals, humans and the environment for food 
security and nutrition.”

In the 2000s, the transdisciplinary nature of agroecological science, combining 
natural and social
sciences, became increasingly important (Wezel et al., 2015). Agroecology was 
identified as “an
integrated discipline that includes elements from agronomy, ecology, sociology 
and economics”
(Dalgaard     et al., 2003). The focus of agroecological science was broadened 
to encompass the whole
agrifood system (Francis et al., 2003; Doré et al., 2006; Gliessman, 2007; 
Wezel and David, 2012;
Côte     et al., eds, 2019) and to cover various topics such as: alternative 
and local food networks;
consumer–producer relationships; social agricultural networks; food markets; 
and public food
procurement.               This food systems’ approach also includes the 
relationships between rural and urban
areas,  leading to the development of urban agroecology (AS PTA, 2011; Almeida 
and Biazo, 2017;
Renting, 2017; Morales et al., 2018; see also Box 4).

Box 4      Urban agriculture

Potentially, urban and peri-urban agriculture (UPA) can play a role in 
enhancing social and
environmental conditions in cities through food security and poverty 
alleviation, although some people
caution       that this should not be overemphasized (Zezza and Tasciotti, 
2010). In Equatorial Africa, Lee-
Smith (2010) found that UPA increases as urban areas expand and that it favours 
improvement in
human health as well as alleviation of hunger and poverty. At a global level, 
Mok et al. (2014) found that
UPA has potential to make significant contributions to food security, although 
more research must be
done around issues such as urban sprawl. On the other hand, some authors 
concluded that UPA has
only  a limited potential to contribute to urban food security in developing 
countries given constraints
related to access to land, water and financial resources to invest in 
productive areas in the urban space
(Badami and Ramankutty, 2015).

UPA is also valued for the environmental benefits that it might promote, such 
as biodiversity
conservation, reduction of food miles and therefore carbon emissions, and 
increasing the green areas in
urban landscapes. UPA in its many forms – allotment gardens, rooftop gardens, 
home orchards, urban
arborization and community gardens, among others – can contribute to a number 
of ecosystem services
such      as pollination, pest control, climate resilience and water regulation 
(Lin et al., 2015). In fact, locally
produced food in urban areas can contribute to create short circuits of 
commercialization, reducing
transportation and also helping to develop direct selling schemes.

Finally, UPA has historically contributed to improve living conditions, 
increase income and alleviate
poverty in cities, strengthening their resilience (Barthel and Isendahl, 2013). 
In many African countries,
where agriculture is the main source of income for the majority of families, 
UPAs may provide a
substantial share of income in addition to promoting a substantial improvement 
in household diets,
contributing    to food security and nutrition (Zezza and Tasciotti, 2010). In 
Mexico City, around 20 percent
of           all food consumed is produced in urban and peri-urban areas; 
however, the recognition of the
importance of UPA in economic terms and as a source of employment is quite 
limited. A symbolic
dimension        of UPAs in Mexico is the pre-Hispanic chinampas system 
(floating gardens) developed by
the     Aztecs that were greatly reduced following European colonization 
(Dieleman, 2017). The
machambas are small agricultural plots in urban and peri-urban areas in 
Mozambique where small
entrepreneurs, in general women, cultivate vegetables to sell in the cities; 
they are an important source
of food and income for many households in cities such as Maputo (Sheldon, 

In the historical evolution of agroecology as a science (Figure 2b), the scale 
and dimension of
research in agroecology have been enlarged from (i) the plot, field or animal 
scale to (ii) the farm or
agroecosystem scale and, finally, to (iii) the whole food system, which is 
increasingly becoming a
focus              for agroecology (Wezel and Soldat, 2009).

Figure 2    Historical evolution of Agroecology

1930s         1940s         1950s         1960s         1970s         1980s     
    1990s         2000s          2010s

A            Elements

Policies for

and laws

and  family

and rights to

Food systems, rural and
territorial development
food sovereignty

Agroecology as a social movement

knowledge         for
natural resource

Agroecological practices are
introduced or further
developed (conservation
agriculture, intercropping,
biological control, etc.)

Agroecological practices
as an alternative paradigm
to conventional agriculture

Agroecology as a set of practices

Scale: field/plot

Scope: biology, zoology,
ecology, crop physiology

From descriptive to analytical

Scale: field and

Scope: ecology, agronomy
Analytical nature

Conceptual framework to
design and manage

agro-ecosystems; from
analytical to prescriptive

Further increases in
disciplines, scope and
scale: agroecology as the
ecology of food systems

Agroecology as a scientific discipline

B         Scale/dimension

Food system

Farm, agroecosystem

Plot, field

C              Disciplines

Agricultural, environmental


Social and cultural

1930s         1940s         1950s         1960s         1970s         1980s     
    1990s         2000s          2010s

Sources:   (A) adapted from Silici (2014), based on Wezel et al. (2009) and 
Wezel and Soldat (2009);

(B) adapted from Wezel et al. (2009).

Note: (C) illustrates the disciplinary basis of the principles of agroecology 
articulated in Section 1.2.

1.1.2   Agroecology as a set of practices

In the 1960s, in particular following the publication of Rachel Carson’s book 
Silent spring (Carson,
1962), concerns emerged about unexpected impacts of the intensive use of 
synthetic inputs in
agriculture on the environment, particularly about the concentration of 
pesticide residues through food
chains impacting birds of prey.

Partly in response to this, a set of agroecological practices emerged over the 
next few decades (see
Section 1.5, Figure 3) aiming at moving away from what has been called an 
“industrial agriculture
model” towards more environmentally friendly and sustainable agricultural 
systems, optimizing the
use of biological processes and ecosystem functions (Hernández Xolocotzi, 1977; 
Rosset and Altieri,
1997; Wezel et al., 2009; Vanloqueren and Baret, 2009; Altieri et al., 2012a; 
Wibbelmann et al., 2013;
Pimbert, 2015; IPES-Food, 2016; FAO, 2016b; Wezel et al., 2014; Deguine et al., 
eds, 2017; Wezel,
2017). Agroecology, as a set of practices, aims at designing complex and 
resilient agroecosystems
that, by “assembling crops, animals, trees, soils and other factors in 
spatially and temporally
diversified schemes, favour natural processes and biological interactions that 
optimize synergies so
that diversified farms are able to sponsor their own soil fertility, crop 
protection and productivity”
(Altieri, 2002).

Attempts to define which specific practices can be qualified as agroecological 
are only recently
emerging. For example, Wezel et al. (2014) describe agroecological practices as 
practices aiming to produce significant amounts of food while valuing 
ecological processes and
ecosystem services by integrating them as fundamental elements”. For Shiming 
and Gliessman
(2016), “agroecological practices are those ecologically sound methods which 
can balance and
enhance all ecosystem services provided by agroecosystems and hence benefit to 
the sustainable
development of agriculture”.

However, there is no definitive set of practices that can be labelled as 
agroecological, nor clear,
consensual boundaries between what is agroecological and what is not (Wezel, 
2017). On the
contrary, agricultural practices can be classified along a spectrum and 
qualified as more or less
“agroecological”, depending on the extent to which: (i) they rely on ecological 
processes as opposed
to                   the use of agrochemical inputs; (ii) they are equitable, 
environmentally friendly, locally adapted and
controlled; and (iii) they adopt a systemic approach, rather than focusing only 
on specific technical

Agroecological practices involve processes such as: nutrient cycling; 
biological nitrogen fixation;
improvement of soil structure and health; water conservation; biodiversity 
conservation and habitat
management techniques for crop-associated biodiversity; carbon sequestration; 
biological pest control
and  natural regulation of diseases; diversification, mixed cultivation, 
intercropping, cultivar mixtures;
and waste management, reuse and recycling as inputs to the production process, 
for example use of
manure and compost (Reijntjes et al., 1992; Altieri 1995; Nicholls et al., 
2016; Wezel et al., 2014;
Wezel, 2017). Agroecological practices include, for instance, agroecological 
responses to new pest
epidemics such as the recent spread of fall armyworm in Africa (Box 5) or 
crop–animal integration in
traditional systems such as the rice–duck–fish system in Asia (Box 6).

Some of these practices have been applied to varying extents in different parts 
of the world for
decades, while others have emerged more recently with as yet limited levels of 
adoption (Wezel et al.,
2014; Wezel and Silva, 2017). For example, organic fertilization, split 
fertilization, reduced tillage, drip
irrigation, biological pest control, integrated pest management and choice of 
resistant/tolerant           to biotic stresses (diseases, insect pests and 
parasitic weeds) are already widely
integrated          into temperate agriculture, in small- and larger-scale 
farms. Biofertilizers, natural pesticides
and biopesticides, diversified rotations, intercropping and relay 
intercropping, agroforestry,
allelopathic plants, direct seeding into living cover crops or mulch, and 
integration of semi-natural
landscape elements at field, farm and landscape scales are less present in 
temperate agriculture, but
prevalent in some tropical contexts (Leakey, 2014). Some agroecological 
practices, such as organic
fertilization and intercropping, came into use with the development of organic 
agriculture in the 1940s.

Box 5      Agroecological practices to control fall armyworm in Africa

Fall armyworm (FAW), a voracious agricultural pest native to North and South 
America, was first
detected on the African continent in 2016 (Goergen et al., 2016). Since then it 
has spread across sub-
Saharan Africa affecting thousands of hectares of cropland, causing up to USD13 
billion per annum in
crop losses (Abrahams et al., 2017) and threatening the livelihoods of millions 
of farmers. In their haste
to respond to FAW, governments have sometimes relied heavily on agrochemicals 
that, beyond the
risks they can pose on human health and the environment, are likely to 
undermine biological pest
management strategies (Abate et al., 2000; van Huis and Meerman, 1997; Wyckhuys 
and O’Neil, 2010).

Agroecological approaches can offer locally adapted, low-cost, biological pest 
control options, including:

•      sustainable soil and land management (e.g mulching), which improves crop 
health and resilience to
pest attack (Altieri and Nicholls, 2003; Clark et al., 1993; Rivers et al., 

•      intercropping, which can reduce egg-laying by pests through deterrence 
by volatile chemicals released
by intercrop plants (Midega et al., 2018), trapping emerging FAW larvae, 
increasing their mortality (van
Huis, 1981) and providing habitat for natural enemies within the field (Rivers 
et al., 2016);

•      crop rotation, which improves soil fertility and diversifies the farm 
environment (Wyckhuys and O’Neil,
2007; Meagher et al., 2016; Rivers et al., 2016);

•      weeds, shrubs, trees and (semi-) natural habitats managed at multiple 
spatial scales, in fields or at field
margins, which can provide habitat for a variety of natural pest enemies 
(Bàrberi et al., 2010; Maas et
al., 2013, 2016; Meagher et al., 2016; Wyckhuys and O’Neil, 2007; Bàrberi et 
al., 2010; Sisay et al.,
2018; Leakey, 2014; Morris et al., 2015; van Huis, 1981; Offenberg, 2015);

•      regular scouting by the farmer to identify pests and assess damage that 
informs pest management
decisions (McGrath et al., 2018);

Agroecological practices are now being advocated as a core component of 
integrated pest management
programmes for FAW in sub-Saharan Africa in combination with crop breeding, 
classical biological
control            and selective use of chemical pesticides (Harrison et al., 
2019; Thierfelder et al., 2018).

Box 6      Traditional rice–fish–duck system in Hani terraces, Southwest China

The rice–fish–duck system is an important traditional agroecosystem in Hani 
terraces in Yunnan
Province, Southwest China. Integration of crops and animals and circular 
economy are at the heart of
this system. Fish and ducks eat weeds and pests and loosen the soil to improve 
the growing
environment for rice, while rice provides food, shade and shelter for fish and 

Pesticides and herbicides cannot be used in this system because of their 
toxicity to fish and ducks.
Therefore, products from rice–fish–duck systems are very popular in consumer 
markets. Their prices
are    usually several times higher than the prices of conventional products. 
For example, the prices of red
rice, fish and ducks raised in paddies in Hani terraces are respectively 5, 3 
and 2.5 times higher than
conventional prices.

An improved rice–fish–duck system has been experimented with in Hani terraces 
and is now
popularized. The agroecosystem efficiently exploits the three-dimensional space 
(and seasonality) of
paddies     for developing rice–fish co-culture during the crop growing season 
while ducks are reared in
winter during the fallow period. Its economic value is estimated to be 7.8 
times that of the current
conventional model that only grows the hybrid rice monoculture in summer for 
half the year and fallows
the       field in winter (Zhang et al., 2017).

This is an example of a Globally Important Agricultural Heritage System (GIAHS) 
that combines
agricultural biodiversity, resilient ecosystems, local communities and a 
valuable cultural heritage.15
There         is a network of 50 GIAHS sites in 20 countries of the world (FAO, 
2002; Koohafkan and Altieri,
2010; Koohafkan and Cruz, 2011; HLPE, 2017b).

¹⁵ See: http://www.fao.org/giahs/en/

1.1.3   Agroecology as a social movement

Traditional agricultural systems, in their diversity, are the result of the 
co-evolution of ecosystems and
human communities across many generations. Therefore, agroecosystems cannot be 
separated from
the human communities living in them: social and political dynamics are at the 
heart of agroecology
(Altieri, 2004b; Wibbelmann et al., 2013; Ploeg and Ventura, 2014).

Agroecological approaches often arise in response to agrarian crises, and along 
with broader efforts
of social movements to initiate widespread changes (Mier y Terán et al., 2018 ; 
Box 7). These social
movements advocate for a strong connection to be made between agroecology, the 
right to adequate
food and food sovereignty.

The concept of food sovereignty was first introduced in international 
discussions during the World
Food Summit in 1996, Rome, by La Via Campesina, an international movement of 
peasants. In 2007,
civil society organizations (CSOs) and social movements gathered in Nyéléni, 
Mali, defined food
sovereignty as “the right of peoples to healthy and culturally appropriate food 
produced through
ecologically sound and sustainable methods, and their right to define their own 
food and agriculture
systems” (Nyéléni, 2007). The initial set of seven principles of food 
sovereignty included: (i) food as a
basic human right; (ii) the need for agrarian reform; (iii) protection of 
natural resources; (iv)
reorganization of food trade to support local food production; (v) reduction of 
concentration               of power; (vi) fostering of peace; and (vii) 
increasing democratic control of the food
system          (La Via Campesina, 1996).

In February 2015, eight years after this first International Forum for Food 
Sovereignty, diverse social
movements and organizations representing small-scale food producers gathered 
again in Nyéléni for
an International Forum on Agroecology (Nyéléni, 2015). In their final 
declaration, they consider
“agroecology as a key element in the construction of food sovereignty”. For 
them, agroecology is not
only “a narrow set of technologies” but, above all, a political struggle, 
requiring people to “challenge
and transform structures of power in society”, addressing power imbalances and 
conflicts of interest,
in order to “generate local knowledge, promote social justice, nurture identity 
and culture, and

strengthen the economic viability of rural areas”.

Agroecology has thus become the political framework under which many social 
movements and
peasant organizations around the world defend their collective rights and 
advocate for a diversity of
locally adapted agriculture and food systems practised by small-scale food 
producers in different
territories (Anderson et al., 2015; Nyéléni, 2015). Agroecology is seen as a 
bottom-up pathway to
food sovereignty, building on traditional knowledge systems, supported rather 
than led by science,
where small producers, their communities and organizations, rather than 
agrifood business, play a
central role. Agroecological approaches aim at building resilient and 
sustainable local food systems,
strongly linked and adapted to their territories and ecosystems (Varghese and 
Hansen-Kuhn, 2013;
Nyéléni, 2015; Anderson et al., 2015). Some national governments have adopted 
policies embracing
the principles of agroecology and food sovereignty in order to transform food 
systems (Altieri et al.,
2012b; Wezel et al., 2009; Lambek et al., 2014).

Box 7      Rede Ecovida in Southern Brazil

The Rede Ecovida or ”Ecolife Network” is a decentralized system of 
cooperatives, farmer groups and
non-profit organizations that practise agroecology in 150 municipalities in 
three southern Brazilian
states. The network developed in the 1970s as part of broader social movements 
mobilizing around
issues of environmental damage from agriculture, of high social inequalities 
and uneven land

Ecovida currently comprises 29 farmers’ organizations, 2 700 farming 
households, 10 cooperatives, 25
associations, 180 farmers’ markets and 30 agrifood private companies. Beyond 
profit, this network
promotes a solidarity economy between producers and consumers in local markets 
(including door-to-
door sales, community canteens, farmers’ markets and restaurants). It uses 
participatory certification to
ensure that farming practices are rooted in agroecology and strengthen the 
among farmers and with urban consumers. Overall, this network promotes 
horizontal learning methods,
solidarity, justice and care for nature.

Sources: Perez-Cassarino (2012); Mier y Terán et al. (2018).

1.1.4   Agroecology as an innovative approach to sustainable food
systems for food security and nutrition

As discussed above, there are an increasing number of definitions for 
agroecology provided in recent
years that have different nuances depending on the authors, institutions or 
CSOs that provide them.
What they have in common is the goal to develop SFSs. Regarding these different 
definitions and the
specific focus of this report on FSN, rather than presenting yet another 
definition of agroecology per
se,      a definition of an agroecological approach to SFSs for FSN is offered 
based on the analysis and
information presented in this chapter (Definition 2).

Definition 2    Agroecological approach to sustainable food systems for food 
security and

Agroecological approaches favour the use of natural processes, limit the use of 
inputs, promote closed cycles with minimal negative externalities and stress 
the importance of
local knowledge and participatory processes that develop knowledge and practice 
experience, as well as more conventional scientific methods, and address social 
Agroecological approaches recognize that agrifood systems are coupled 
systems        from food production to consumption and involve science, 
practice and a social
movement, as well as their holistic integration, to address FSN.

1.2  Principles of agroecology

Scientists have developed different sets of agroecological principles 
(Reijntjes et al., 1992; Altieri,
1995; Altieri and Nicolls, 2005; Stassart et al., 2012; Dumont et al., 2013, 
2016; Nicholls et al., 2016;
Peeters and Wezel, 2017; all summarized in Migliorini and Wezel, 2018). Civil 
society networks also
conducted the same exercise (e.g. Nyéléni, 2015; CIDSE, 2018). Today, 
agroecology is associated
with        a set of principles for agricultural and ecological management of 
agrifood systems as well as
some wider ranging socio-economic, cultural and political principles (e.g. 
CIDSE, 2018). These latter
principles have emerged only recently in the literature, arising from the 
activity of agroecological
social movements (Figure 2c).

FAO (2018c) identified ten elements of agroecology to guide the transition 
towards sustainable
agriculture and food systems.16  These consolidated FAO ten elements are based 
upon seminal
scientific literature on agroecology (in particular: Altieri, 1995; Gliessman, 
2007) and upon the
extensive     and inclusive multi-stakeholder dialogues, gathering states and 
organizations, CSOs and private actors, held at global, regional and national 
levels since the first FAO
International Symposium on Agroecology (September 2014).

Building on all these efforts, the HLPE elaborated a consolidated list of 13 
principles, combining and
reformulating principles from the three principal sources (Nicholls et al., 
2016; CIDSE, 2018; FAO,
2018d) to produce a minimum, non-repetitive but comprehensive set of 
agroecological principles.

These are organized around the three operational principles for SFSs set out in 
the introduction –
improve resource efficiency, strengthen resilience and secure social 
equity/responsibility (see
Table 1). Each agroecological principle was allocated to the operational 
principle to which it most

clearly contributes. However, given the interlinkages among these three 
categories, this classification
is not fully discrete. For example, principles 3, 5 and 6 contribute not only 
to resilience but also to
resource efficiency. Principles are also related to the FAO ten elements.17

¹⁶  Diversity; co-creation and sharing of knowledge; synergies; efficiency; 
recycling; resilience; human and social values;
culture and food traditions; responsible governance; circular and solidarity 

¹⁷  See: http://www.fao.org/3/i9037en/I9037EN.pdf

Different principles can be implemented at or impact different scales, from 
local to global, from the
field to the whole food system. At the agroecosystem or landscape scale, some 
ecological processes,
such as water flows, operate over large distances so that what farmers do in 
one location may impact
other people positively (clean water supply) or negatively (flooding or 
contaminated water) many
kilometres away, across administrative and national boundaries (Jackson et al., 
2013). Soil eroded
from      one place may be deposited and support food production elsewhere. 
Recent research has
shown that not only surface water flow but also atmospheric transfers across 
continents are
important,     so that change in vegetation cover in the East African highlands 
impacts rainfall and hence
agricultural productivity in the Sahel (van Noordwijk et al., 2014).

This means that concepts of resource cycles and flows (principles 1 and 5) need 
to be related to the
scales at which they operate, and many ecosystem services, such as pollination, 
quantity and quality
of water provision and habitat provision for biodiversity conservation, only 
manifest at landscape scale
and, hence, can only be managed by collective action of farmers and other 
stakeholders (Pagella and
Sinclair, 2014). Application of agroecological principles often aims at 
reducing externalities associated
with current models of agricultural production. Measuring and valuing ecosystem 
service provision at
a range of scales is a key area of innovation required to measure performance 
of food systems in
ways that address their sustainability. This is further developed in Chapters 2 
and 3.

All these agroecological principles contribute, in different direct and 
indirect ways, to FSN. For
instance, principle 2 (reducing the dependency on purchased inputs) can reduce 
food insecurity in
particular for smallholders and for poor farmers because less money is spent on 
buying inputs and so
there  is less reliance on credit and, therefore, potentially more resources to 
buy food (Snapp et al.,
2010; Kangmennaang et al., 2017; Hwang et al., 2016). This is a primary 
motivation for the Zero
Budget Natural Farming (ZBNF) agroecological movement in India (Box 8). 
Principle 9 (social values
and diets) together with 5 (biodiversity) impact nutrition directly (Jones et 
al., 2014b; Powell et al.,
2015; Bellon et al., 2016; Demeke et al., 2017; Lachat et al., 2018; HLPE, 
2017a,b). Co-creation of
knowledge (principle 8) can also have indirect positive impacts on FSN (Box 9). 
Principle 11
(connectivity)  may contribute to strengthen local economies, increasing the 
proportion of value added
remaining on farms and enabling producers to better meet the food needs and 
demands of local
consumers. This latter point can be supported by strong social organizations, 
which foster greater
participation of local food producers and consumers in decision-making 
(principle 13).

Table 1     Consolidated set of 13 agroecological principles

                          FAO’s ten



Improve resource efficiency

1. Recycling. Preferentially use local renewable resources and close
as far as possible resource cycles of nutrients and biomass.

2. Input reduction. Reduce or eliminate dependency on purchased
inputs and increase self-sufficiency

Recycling                   FI, FA

Efficiency                    FA, FO

Strengthen resilience

3. Soil health. Secure and enhance soil health and functioning for

improved plant growth, particularly by managing organic matter and              
enhancing soil biological activity.

4. Animal health. Ensure animal health and welfare.

5. Biodiversity. Maintain and enhance diversity of species, functional
diversity and genetic resources and thereby maintain overall
agroecosystem biodiversity in time and space at field, farm and
landscape      scales.

6. Synergy. Enhance positive ecological interaction, synergy,
integration and complementarity among the elements of
agroecosystems (animals, crops, trees, soil and water).

7. Economic diversification. Diversify on-farm incomes by ensuring
that small-scale farmers have greater financial independence and value
addition opportunities while enabling them to respond to demand from

Part of diversity


Part of diversity




Secure social equity/responsibility

8.Co-creation of knowledge. Enhance co-creation and horizontal
sharing of knowledge including local and scientific innovation,
especially through farmer-to-farmer exchange.

9. Social values and diets. Build food systems based on the culture,
identity, tradition, social and gender equity of local communities that
provide healthy, diversified, seasonally and culturally appropriate diets.

10. Fairness. Support dignified and robust livelihoods for all actors
engaged in food systems, especially small-scale food producers, based
on   fair trade, fair employment and fair treatment of intellectual property

11. Connectivity. Ensure proximity and confidence between producers
and consumers through promotion of fair and short distribution
networks and by re-embedding food systems into local economies.

12. Land and natural resource governance. Strengthen institutional
arrangements to improve, including the recognition and support of
family farmers, smallholders and peasant food producers as
sustainable managers of natural and genetic resources.

13. Participation. Encourage social organization and greater
participation in decision-making by food producers and consumers to
support decentralized governance and local adaptive management of
agricultural and food systems.

*Scale application: FI = field; FA = farm, agroecosystem; FO = food system

Source: derived from from Nicholls et al., 2016; CIDSE, 2018; FAO, 2018c.

Co-creation and
sharing of

Parts of human
and social values
and culture and
food traditions

Circular and
solidarity economy








It has been suggested that for agroecology to significantly impact FSN and 
generate sustainable
diets,18  power inequalities must be addressed within the food system at 
multiple scales and in
different dimensions (HLPE, 2017a; Mier y Teran et al., 2018; Pimbert and 
Lemke, 2018). Horizontal
teaching methods (principle 8) are options for agroecology to address social 
inequalities; principles
10–13 articulate how other inequalities can be addressed as part of an 
agroecological approach.

Potential trade-offs must also be considered in each specific context. For 
instance, depending on
quantity and type of inputs, reduced input use (principle 2) could lead to 
lower productivity, lower
income and thus higher food insecurity. In addition, agroecological methods, if 
more labour-intensive,
could increase women’s workload, leading to worsening the nutritional status of 
children if gender
relationships within households are not changed (principle 9).

Box 8      Zero Budget Natural Farming – Scaling-up agroecology in India

Zero Budget Natural Farming (ZBNF) is both a set of farming methods and a 
grassroots peasant
movement in India born in Karnataka. It is estimated that ZNBF methods are used 
by 100 000 farming
families in Karnataka, and by millions of families at the national level. In 
2015 the Government of
Andhra Pradesh announced its objective to reach 500 000 farmers with ZBNF by 

Interest in ZBNF methods arose partly because of the high rates of farmers’ 
debt, originating from the
costs of fertilizers, seeds, energy and equipment (mechanization and 
irrigation), which have been linked
to high suicide rates. More than a quarter of a million farmers have committed 
suicide in India in the last
two decades.

”Zero Budget”, which means not relying on credit, and not buying inputs, 
promises to put an end to
heavy debt, by drastically reducing production costs. “Natural Farming” means 
farming with nature and
without purchased chemical inputs. ZBNF methods include: mulching; 
intercropping; controlled
irrigation; contour bunds; use of local earthworm species and fermented 
microbial culture; combined
seed treatment with cow dung, sugar, pulse flour, urine and soil.

At the local level, ZBNF operates mainly through volunteers, members of farmer 
organizations and
community leaders, motivated by the founder of the movement, Subhash Palekar, 
an agricultural
scientist        who has written many publications on ZNBF methods. At the 
state level, intensive five-day
training camps are held, with support from volunteers and allied organizations. 
A survey of 97 ZBNF
farmers reported increased yield, seed diversity, product quality, household 
food autonomy, income and
health, along with reduced farm expenses and credit needs.

The following strategic elements were critical for the successful 
implementation of ZBNF in India:

•      Charismatic leadership. A highly charismatic teacher, Subhash Palekar 
has played a key role in
motivating and promoting ZBNF methods through books, training courses and other 

•      Horizontal pedagogical practices. While Palekar teaches in a more 
vertical manner, most of the
teaching is done through farmer-to-farmer exchanges and mentoring.

•      Supportive public policy. Training is provided at the state level in 
several Indian states.

•      Local and favourable markets. At least eight shops exclusively retail 
ZBNF products in cities such
as Bangalore and Mysore, but marketing remains a challenge.

•      Strong social organization. States organize training camps and informal 
networks support training
and ongoing support for ZBNF with links to allied organizations.

•      Efficient farming practices. Farmers report improved yields, food 
quality and income, and reduced
farm expenses and credit.

•      Cultural relevance. ZBNF methods address the credit and debt concerns of 
farmers in socially and
culturally adapted ways.

Sources: Khadse et al. (2018) ; Kumar (2018); La Via Campesina (Undated)

¹⁸  “Sustainable diets are those with low environmental impacts which 
contribute to food and nutrition security and to
healthy life for present and future generations. Sustainable diets are 
protective and respectful of biodiversity and
ecosystems, culturally acceptable, accessible, economically fair and 
affordable; nutritionally adequate, safe and
healthy; while optimizing natural and human resources” (FAO, 2012a).

Box 9      Participatory agroecology research to address food security and 
nutrition in

Using participatory education and agroecology in Malawi, thousands of rural 
families have seen
dramatic improvements in maternal and child nutrition, food security, crop 
diversity, land management
practices and gender equality. Central to the success of this long-term 
programme has been iterative,
participatory, transdisciplinary research methods that used multiple measures 
to assess and improve
farming      and social change with participating farmers (Bezner Kerr and 
Chirwa, 2004;  Nyantakyi-
Frimpong    et al., 2017). Agroecology education was integrated with nutrition 
and social equity issues
through interactive, dialogue-based methods, such as recipe days, discussion 
groups and theatre
(Satzinger  et al. 2009;  Bezner Kerr et al., 2016a; Bezner Kerr et al., 
2018a). Peer-driven farmer-led
methods mobilized communities to test and use agroecological practices such as 
legume intercrops,
compost, agroforestry and crop diversification (Bezner Kerr et al., 2007;  
Bezner Kerr et al. 2018b;
Owoputi       et al., 2018). When farmers used more agroecological practices, 
such as the incorporation of
nutrient-rich legumes into maize-based cropping systems, yields stabilized, 
fertilizer costs fell and soil
cover increased (Snapp et al., 2010;  Kangmennaang et al., 2017; Owoputi et 
al., 2018). Households
using agroecological practices who participated in community education 
programmes had significant
improvements in child growth, food security, maternal dietary diversity and 
self-reported health (Bezner
Kerr             et al., 2010; Nyantakyi-Frimpong et al., 2016a; Owoputi et 
al,. 2018). There was also evidence of
improved gender and other forms of social equity in communities for households 
with HIV-positive
family members (Bezner Kerr et al., 2016b, 2019; Nyantakyi-Frimpong et al., 
2016b). In households
where spouses began discussing farming practices with each other, there were 
higher levels of food
security and dietary diversity. Farmers began to take more pride in their own 
experimentation, traditional
knowledge and ability to mentor others (Bezner Kerr et al., 2018b). Some 
communities organized the
sharing      of seeds and agroecological knowledge, and reported greater 
resilience under conditions of
poor rainfall due to improved soil quality (Bezner Kerr et al., 2018b, 2019).

Key findings from the case study:

•      Farmer-to-farmer teaching and experimentation were the primary teaching 
approaches and were
effective at sharing knowledge.

•      Unequal social relationships including gender inequalities were 
assessed, discussed and improved
over time.

•      Relevant educational strategies were developed by local communities to 
address these inequalities in
an iterative way.

•     Linking agroecology to FSN outcomes took at least two years before such 
outcomes were realized,
and required transdisciplinary and participatory approaches.

1.3  Contribution of agroecological approaches to food security
and nutrition for rural consumers in low-income countries

Not only do agroecological practices contribute to FSN, but they also 
contribute to 10 of the 17  SDGs
(UN, 2015) through integrated practices that cut across many areas (FAO, 2018a) 
and help address
poverty and hunger, education, gender equality, decent work and economic 
growth, reduced
inequalities, responsible consumption and production, climate action, life on 
land, and peace and
justice.     Along with the SDGs, agroecology can also contribute to the 
Koronivia Joint Work on
Agriculture (KJWA) (St-Louis et al., 2018) on adaptation, soils, nutrient use, 
manure management and
livestock systems (see points 2.c, 2.d, and 2.e of the KJWA), and help realize 
the aims of the Paris
Climate Agreement, the CBD and the United Nations Convention to Combat 
Desertification (FAO,

Beyond yield and production, an assessment of the contribution of 
agroecological approaches to FSN
needs to incorporate multiple metrics that take into account social, economic 
and environmental
impacts  of agriculture.

Agroecological approaches could play an important role in securing sustainable 
diets for all now and
in the future as part of a transition towards more sustainable food systems 
that enhance FSN (De
Schutter, 2011, 2012; IPES-Food 2016, DeLonge et al., 2016). Numerous studies 
have found positive
relationships between diversified farming systems (a key principle of 
agroecology), household dietary
diversity and nutrition (Talukder et al., 2000; De Clerck, 2013; Oyarzun et 
al., 2013; Jones et al.,
2014b; Khoury et al., 2014; Carletto et al., 2015; Kumar et al., 2015; Olney et 
al., 2015; Shively and
Sununtnasik, 2015; Jones, 2017).

Bliss et al. (2017) examined the diversified farming systems of 30 Nicaraguan 
households. For the
farmers, dietary diversity was a driver for diversification on fields, and the 
related higher crop diversity,
with difference in harvest time, meaning greater food availability throughout 
the year. In Southern
Benin, Bellon et al. (2016) found a positive correlation between on-farm 
diversity and women’s dietary
diversity score (DDS),19  as most of the food grown on-farm was for consumption 
rather than for sale.
Jones  et al. (2018) also found that on-farm agrobiodiversity was associated 
with more diverse and
micronutrient-adequate diets among women in the Peruvian Andes.

In a survey of 390 households in Mexico, Becerril (2013) found improved body 
mass indexes in
households using the diversified traditional “milpa” system (intercropping of 
maize, beans and
squash) compared to other households with less diversified farming systems. In 
their study on
Guatemala's Mayan Achí people, Luna-González and Sørensen (2018) found that 
functional diversity and DDSs were positively correlated with higher crop and 
animal species diversity
(derived from traditional intercropped milpa systems, home gardens, local 
market, wild gathering) but
higher DDDs were not correlated with better child anthropometric status. Other 
factors, such as
limited access to health care or safe water, may have prevented improved child 
growth. In northern
Malawi, studies have shown that legume intercropping, along with a 
participatory approach sensitive
to cultural values and promoting gender equality, enhanced both food and 
nutritional security (Bezner
Kerr et al., 2016c; Nyantakyi-Frimpong et al., 2016b; see Box 9). These results 
are especially
significant as many Malawian households experience food insecurity and 
malnutrition (Ecker and
Qaim, 2011) leading to poor health outcomes including stunting in young 
children (FAO, 2014a).

In Uzbekistan, Gotor et al. (2018), studying a programme related to 
conservation and use of fruit
species, showed that families growing more fruit species consumed a greater 
proportion of fruits in
their diets, increasing their dietary diversity. Dawson et al. (2013) showed 
that agroforestry practices
exploit differences in the phenology of fruit-tree species to provide critical 
nutritional supplements
(particularly Vitamins A, C and B6) and maintain dietary diversity throughout 
the year. They
highlighted           that their extensive root systems allow trees to store 
water, be productive and contribute
to      dietary diversity, even in dry environments, in seasons when herbaceous 
vegetation cannot survive
without irrigation. In Machakos (Kenya), an average household can achieve 
year-round dietary
diversity  with 20 trees of ten species either dispersed throughout their farm 
(on borders, around the
home and in fields) or in a 8×18 m² (0.015 ha) fruit orchard (Kehlenbeck and 
McMullin, 2015). In a
survey of 368 coffee-producing households, Bacon et al. (2017) found that food 
security was
enhanced    for agroforestry farmers who grew more of their own food and 
incorporated more diversified
production elements including fruit trees and red bean crops. However, the 
authors cautioned that not
all diversification is equally beneficial to different parameters of FSN. A 
meta-analysis revealed a
significant positive relationship between indicators of dietary quality of 
children under five and
landscape-scale tree cover in Africa, associated with maximum fruit and 
vegetable consumption at an
intermediate level of tree cover (45 percent), after which it declines 
(Ickowitz et al., 2014).

Diversified production in home gardens with application of agroecological 
practices provides an
avenue for FSN for poor households with limited access to food. Home gardeners 
in Ghana, using
intercropping, seed-saving, organic manures and crop residues as well as 
domestic waste,
contributed                to greater food availability, food access and 
nutrient supply (Bagson and Naamwintome,
2012). Vijayalakshmi and Thooyavathy (2012) found similar results in a study 
looking at the impact of
home gardens on women's nutrition. In a small-scale study of 12 households in 
Bangladesh, Ferdous
et al. (2016) highlighted a drastic increase in vegetable consumption among 
households trained in the
Rangpur model (a home-garden strategy based on seven production niches, 14 
vegetables selected
for year-round cultivation, fruit and locally adapted crops). After the 
intervention, vegetable intake
almost doubled, with 55–79 kg/person/year produced compared to 21–30 
kg/person/year before the

Several studies revealed a positive impact of organic farming practices on FSN 
(Miyashita and
Kayunze, 2016; da Silva et al., 2018; Kamau et al., 2018). Miyashita and 
Kayunze (2015), for
example,    found significant differences in terms of FSN when they compared 
organic and conventional
farming in the United Republic of Tanzania. On the other hand, the study of 139 
farming households
by Kaufman (2015) in northern Thailand showed variable impact of organic 
agricultural systems on
food security when compared to conventional counterparts. While organic farmers 
had slightly higher
mean levels of food security and lower debt levels compared to conventional 
farmers, the findings

¹⁹ For more information about DDS see http://www.fao.org/3/a-i1983e.pdf

were not statistically significant (Kaufman, 2015). The author concludes that 
greater support for viable
markets for organic products is needed to translate into significant 
differences in FSN for organic
producers (Kaufman, 2015).

In contrast, some studies also showed no significant relationship with the 
application of agroecological
practices and measured parameters related to FSN. For instance, on-farm 
diversification in Nigeria
had        no impact on household DDS for the poorest surveyed households, 
although greater diversity
was evident with middle- and high-income households (Ayenew et al., 2018). In 
Kenya, Ng’endo et al.
(2015). also found no significant correlation between agrobiodiversity and 
households’ FSN.

1.4  Contested areas and knowledge gaps in agroecology

There is no common, consensual definition of what constitutes an agroecological 
approach shared by
all the actors involved (practitioners, scientists, social activists). Complete 
agreement on all the
aspects embedded in the plurality if approaches or on how it should contribute 
to transformation of
food systems is also lacking. While this makes it hard to pin down exactly what 
is agroecology and
what is not, it also provides a flexibility that allows agroecological 
approaches to develop in locally
adapted ways. It is thus necessary to examine key contested areas and knowledge 
gaps, which is the
aim of this section.

1.4.1   Political and social dimensions of food production

Some scientists, food-system actors and social movements have diverging views 
about whether
social and political dimensions of food production should be considered as an 
integral and indivisible
part of agroecology, critical for agroecology to be transformative (Méndez et 
al., 2013; Rosset and
Altieri, 2017; Sanderson Bellamy and Ioris, 2017; Giraldo and Rosset, 2018). De 
Molina (2013)
argues that not recognizing the social and political implications of 
agroecology could lead to negative
social, environmental and FSN consequences for marginalized groups who may be 
with   a “business as usual” model of agricultural improvement. This argument 
is in line with research
on how political, social and economic context determines how technology is 
employed in addressing
FSN (Bezner Kerr, 2012; Gómez et al., 2013; Stone and Glover, 2017).

Some authors have suggested distinguishing a political or transformative 
agroecology, considering
political and social factors to address FSN at a broader scale, from a 
technically-focused agroecology
at  the field scale (Méndez et al. 2013; Sanderson Bellamy and Ioris, 2017).

Attention has in particular been drawn to the importance of addressing 
context-specific gender and
social inequalities and related labour and economic dimensions through 
agroecological approaches
(Batello et al., 2019; Bezner Kerr et al., 2019). Other authors have noted that 
agroecology, when
embedded within a larger food systems policy intervention or food sovereignty 
initiative, can have a
positive impact on FSN (Kanter et al., 2015; Wittman and Blesh, 2017).

A just food system (Pimbert and Lemke, 2018) addresses wages and working 
conditions within it
(principle 10) creating a direct link to FSN. Improved livelihoods for farm 
labourers, producers, market
intermediaries, entrepreneurs and processors may enable them to achieve higher 
incomes and,
therefore,  purchase food. Increased proximity of producers and consumers and 
re-embedded local
food systems (principle 11) may contribute to improving local economies. For 
example, producers can
profit by receiving a higher share of revenue if less is taken by 
intermediaries or actors over a long
supply chain for marketing and distribution of produce. Also, local food 
enterprises and retailers can
increase their price margins and become better linked and known to local 
consumers. An important
point here is also that producers can respond more effectively to the real food 
needs and demands of
local consumers. This latter point is strongly supported by social 
organizations, which foster greater
participation and decision-making of food producers and consumers (principle 

1.4.2   Difficulty in providing labels: illustration through the convergence
with organic agriculture

As agreeing on a generic definition proves to be difficult, so it is to provide 
universal label and
labelling mechanisms. Yet, some initiatives by stakeholder groups and companies 
are under way.
One form of certification that is suggested is the participatory guarantee 
system (PGS), in which
certification is done using a democratic process involving producers, 
scientists and consumers
(see        Box 32 in Appendix 1).

This may also generate difficulties when addressing distinction with other 
innovative approaches.
There is, for example, a growing debate about similarities, difference and 
convergence of organic
agriculture and agroecology (Migliorini and Wezel, 2018). There is also related 
debate about whether
synthetic pesticides and chemical fertilizers should be excluded from 
agroecological production, as
under organic agriculture (with a few exceptions), or be acceptable to a 
certain degree or in defined

1.4.3   Can agroecology feed the world?

Some people think that farmers cannot feed the world with agroecology, others 
contend that it is
impossible to feed the world in the future without agroecology. These echo 
divergent views on
whether organic farming could feed the global population (De Ponti et al., 
2012, Muller et al., 2017).

It is commonly estimated that an increase in agricultural production will be 
required to feed a growing
global population, expected to reach 9.7 billion by 2050, unless major changes 
are made in global
food systems (HLPE, 2016; Berners-Lee et al., 2018; Le Mouël et al., eds, 
2018), especially in Africa
(van Ittersum et al., 2016). Estimates vary depending on whether food losses 
and waste, urbanization
and changing diets, non-food uses (animal feed, biofuels and others) are 
considered in the modelling
(HLPE, 2013b, 2014; Kahane et al., 2013; Keating et al., 2014; Berners-Lee et 
al., 2018; Le Mouël et
al., 2018; Keating and Carberry, 2010; Alexandratos and Bruinsma, 2012; Valin, 
2014). FAO (2017b)
estimated that global agricultural production would have to increase by almost 
50 percent

between 2012 and 2050.

However, the need for such an increase in agricultural production is contested, 
as the earlier
assumptions are challenged: some estimates indicate that enough food is 
produced today to
potentially feed 9 billion people (IPES-Food, 2016; HLPE, 2014, 2017b; 
Chappell, 2018) or even

9.75 billion (Berners-Lee et al., 2018). The debate as to whether or not 
agroecology can feed the
world may be based on a false premise since, despite high levels of production, 
food insecurity and
malnutrition still persist today (Chappell, 2018; HLPE, 2016, 2017b), even in 
food-exporting countries
such      as Brazil and South Africa (FAO et al., 2017). Today, almost 
one-third of food produced for
human consumption is either lost or wasted, yet different forms of malnutrition 
coexist in most
countries (HLPE, 2014, 2017b). Globally, around  820 million people are still 
hungry (FAO et al.,
2018),  about 2 billion are overweight or obese (Ng et al., 2014) and an 
estimated 2 billion people
suffer from malnutrition caused by micronutrient deficiencies (iron, iodine, 
vitamin A, folate and zinc)
(HLPE, 2017b). FAO (2018e) found that a “business as usual” scenario is likely 
to lead to significant
undernourishment by 2050 even if gross agricultural output increases by 50 
percent. On the contrary,
alternative “towards sustainability” scenarios, through more balanced diets, 
more sustainable
production      and consumption patterns, as well as through fairer food and 
income distribution, in line
with agroecological approaches, could lead to a drastic reduction in 
undernourishment and
improvement of nutritional security even if agricultural production increases 
only by around

40 percent.

Increasing production alone might thus not be sufficient to achieve FSN in its 
four dimensions
(availability, access, utilization and stability) (FAO, 2018b). There is a 
growing awareness that hunger
and malnutrition may not be only a matter of food production, but mainly of 
different entitlements,
leading to unequal access to food, to natural resources (land, water, genetic 
resources), inputs,
markets and services (Sen, 1981; Smith and Haddad, 2015; HLPE, 2017b). Previous 
HLPE reports
have extensively discussed the issues raised by inequalities in access to food 
and resources (see in
particular: HLPE, 2011a,b, 2012, 2013a, 2015, 2016, 2017c). Therefore, 
agroecological approaches
are presented as promising avenues to achieve FSN, since they do not consider 
productivity alone
and suggest addressing social inequalities and power asymmetries (Massett et 
al., 2011 ; Kanter et
al., 2015; HLPE, 2018), including gender and ethnic minority inequalities 
(Massicotte, 2014; Bezner
Kerr et al., 2019).

Furthermore, ”feeding the world” is sometimes framed as a question of calories 
or production, and
includes debates about the nutritional implications of different farming 
systems (HLPE, 2017b).

Meeting kilocalorie energy requirements, however, does not translate 
automatically into nutritional
security (Pingali, 2015; Traore et al., 2012; Keating et al., 2014), as some 
forms of calorie
consumption (e.g. foods with high sugar, salt or fat content) can worsen 
nutritional status (HLPE,
2017b).   FSN indicators now go beyond calorie count, and include measures of 
child growth, diet
quality and reported experience of food insecurity at the individual and 
household level (Arimond et
al., 2010; Carletto et al., 2012).

In many parts of the world, the so-called “industrial” agriculture model 
relying on the intensive use of
fossil fuel and chemical inputs has resulted in increased agricultural 
productivity at the expense of
loss    of biodiversity, land degradation, loss of soil fertility and chemical 
contamination of soil and water,
with major consequences on human, animal and planetary health (Kremen and 
Miles, 2012). A
number of recent studies suggest that industrial agriculture cannot ensure 
sustainable food systems
for   FSN in the long term because of these negative impacts (Campbell et al., 
2017; Frison et al.,
2011; IPES-Food, 2016; Mahon et al., 2017; Kremen and Merenlender, 2018). The 
consequences of
such production systems in terms of diet imbalance are increasingly a polemical 
issue, which calls for
increased attention from consumers (HLPE, 2017b).

Moreover, several studies challenged the common idea that agroecological 
systems are less
productive than more “conventional” or “industrial” agricultural models 
(intensive and specialized), and
thus cannot make a large contribution to feeding the world.

For example, Poux and Aubert (2018) have recently modelled the potential for 
approaches (including elimination of pesticides and synthetic fertilizers, 
shifting to healthier diets, and
development of hedges, trees, ponds and other habitats for increased 
biodiversity) to feed Europe.

They estimated that production would decline by 35 percent but that food 
requirements for Europe
and for the export market in cereals, dairy and wine would be maintained, 
greenhouse gas emissions
would be reduced by 45 percent and biodiversity and natural resources improved. 
Pretty et al. (2003),
De Schutter (2010, 2012, Ponisio et al. (2015) and Reganold and Wachter (2016) 
summarized many
examples, mainly from tropical and subtropical countries, showing significant 
yield increases
associated      with agroecological or organic farming. Pretty et al. (2003) 
showed that the weighted
average increases were 37 percent per farm and 48 percent per hectare, while 
d’Annolfo et al. (2017)
showed in their meta analysis that, following the adoption of agroecological 
practices, yields
increased        in 61 percent of the cases analysed and decreased in 20 
percent, while farm profitability
increased in 66 percent of cases.

Given the underinvestment in agroecological research noted below, it remains 
unclear how
representative the cases so far documented are and which aspects of the 
agroecological approaches
adopted were responsible for yield and profit improvements.

1.4.4   Knowledge systems

There are debates around the role and contribution of indigenous and local food 
producers in
knowledge generation and the significance of cultural context for shaping this 
knowledge, including
the         role of women, elders, ceremonies, community organizations and 
opportunities for interaction with
scientists (IAASTD, 2009; Etkin, 2006; Méndez et al., 2013; Snapp and Pound, 
eds, 2017; IIED,
2018).    Local knowledge is used here to refer to the knowledge held by a 
defined group of people
(Sinclair and Walker, 1999). It embraces traditional knowledge (passed down 
from one generation to
the next), indigenous knowledge that is culturally bound and locally derived 
knowledge from
contemporary learning based on local observation and experimentation (Sinclair 
and Joshi, 2004).

Some argue that traditional knowledge is deep, but narrow, while scientific 
knowledge is broad but
shallow, and that agroecology involves the co-production of knowledge through 
the mutual shaping of
different knowledge streams (Vandermeer and Perfecto, 2013). Scholars and 
indigenous groups also
debate the notion that local knowledge is ”new” scientific knowledge and 
caution about the dangers of
such knowledge being separated out from other social–ecological knowledge 
(Barthel et al., 2013;
Massicotte, 2014; IIED, 2018). There is mounting evidence that much local 
agroecological knowledge
is dynamic, based on contemporary observation and experimentation by farmers 
and comparable with
and largely complementary to global scientific knowledge (Richards, 1985; 
Sinclair and Walker, 1999;
Thorne et al., 1999; IAASTD, 2009;Cerdán et al., 2012; Kuria et al., 2018). 
While some agroecological
knowledge is widely held by people living in a particular locality (Joshi et 
al., 2004), in other cases
different people within communities may have different interests and 
opportunities to observe
agroecological processes leading to marked differences in knowledge according 
to gender or other
forms               of social differentiation (Crossland et al., 2018).

Debates about the roles of farmers and social movements in agroecological 
knowledge and
agroecological research relate to the potential to ”scale-out” agroecology 
effectively (Pimbert, ed,
2018a). Several scholars and social movements in the ”political agroecology” 
stream have
emphasized the significance of democratic processes in agroecological knowledge 
generation, with
the process of small food producer-led, decentralized, autonomous knowledge 
generation being as
important as the specific technical knowledge being generated through more 
formal scientific

approaches (Massicotte, 2014). Researchers have also pointed to the need for 
agroecology to
explicitly address gender, ethnic minorities and other social inequalities in 
order to effectively impact
FSN (Massicotte, 2014; Bezner Kerr et al., 2019).

These issues can create tensions between social movements and scientists. This 
may happen when
the way science generates knowledge and judges its validity is not respected, 
when ethics and social
control of scientific production are not addressed, when the contribution of 
non-academic actors in
knowledge production is not considered. This is especially the case when 
investment decisions are
being   made and power imbalances exist. Consideration of these situations has 
led to explicit attempts
to bridge across different knowledge systems (Mendez et al., 2013; Tengö et 
al., 2014).

1.4.5   Knowledge gaps

The severely limited public investment in agroecological approaches, estimated 
at between 1 percent
and 1.5 percent of total agricultural and aid budgets, partly explains the 
remaining knowledge gaps
(DeLonge et al., 2016; Miles et al., 2017; Pimbert and Moeller, 2018). Most 
private and public
investments     in agricultural research over the last 50 years were primarily 
based on “Green
Revolution” technologies (including agrochemicals and mechanization) and, in 
particular, on genetics
(Vanloqueren and Baret, 2009; DeLonge et al., 2016; Miles et al., 2017; Pimbert 
and Moeller 2018).
For   example, in the United Kingdom, aid for agroecological projects 
represents less than 5 percent of
agricultural aid and less than 0.5 percent of its total aid budget since 2010 
(Pimbert and Moeller,
2018). In the United States of America, research and development related to 
diversified systems – a
major avenue for agroecological systems – amounts to less than 2 percent of 
public agricultural
research funding (Carlisle and Miles, 2013). FAO estimates that 8 percent of 
their 2018–2019 work
contributes to agroecological transitions (FAO, 2018f).

In addition, the majority of teaching and research institutions, and extension 
services, have been
oriented to the so-called “industrial” agriculture rather than to the promotion 
of agroecological
technologies. Typical education programmes in agronomy are mostly oriented 
towards single solution
problem solving in conventional agriculture. There is now a growing number of 
education programmes
that bring more systemic and holistic approaches, as well as experiential 
learning, into focus (Francis
et al., 2011, 2017).

Therefore, comparisons between agroecological approaches and the dominant 
“industrial” agriculture
model need to consider the funding bias skewed against agroecological research, 
education and
extension (Delonge et al., 2016; Pimbert and Moeller, 2018).

Two key knowledge gaps are how to effectively link agroecology to public 
policies to address FSN
(Sabourin et al., 2018), and what are the economic and social impacts of 
agroecology for different
groups in communities, including labour costs and FSN (Sanderson Bellamy and 
Ioris, 2017; Bezner
Kerr et al., 2019).

Assessing the yield gap between “industrial” and agroecological systems is an 
active area for
research. Although several studies suggest that there are comparable yields, 
higher yield stability,
particularly under extreme weather conditions, and increased profitability for 
those using
agroecological methods, further research is required, in a wider range of 
socio-ecological conditions
(d’Annolfo  et al., 2017; Sanderson Bellamy and Ioris, 2017).

How to scale out agroecological approaches in ways that foster democratic 
processes and address
the needs of marginalized groups is also lacking, with some evidence for 
context-specific methods
being effective at addressing FSN and SFSs, if political and economic barriers 
are addressed (IPES-
Food, 2016; Mier y Terán et al., 2018; Sinclair and Coe, 2019).

The design of resilient agricultural systems is an imperative to cope with 
climate change and
increased climate variability. Resilience is particularly important in areas 
most likely to be affected by
extreme climate events such as prolonged droughts, floods and heavy winds 
(Ching et al., eds, 2011;
Koohafkan et al., 2012; Rhodes, 2013; Scialabba and Müller-Lindenlauf, 2010; 
Altieri et al., 2015).

Holt-Giménez (2002) indicated that agroecological systems are more adapted to 
such context, and
might even help mitigate the effects of climate change. However, further 
research is needed to better
understand the processes that support more resilient systems in different 
contexts. Many gaps remain
in     terms of how to support such transitions and what are the key barriers 
to overcome (Gliessman,
2016; Côte et al., 2019). Several ”lock-ins” that may prevent the transition 
towards agroecological