The potential of agroecology to combat hunger in the developing world

Miguel Altieri, Peter Rosset and Lori Ann Thrupp explain the meaning of agroecology and its importance in resolving the crucial problems of hunger, inequality and sustainable development in the developing world.

HUNGER and malnutrition affect nearly 800 million people in the developing world. By and large these problems are not due to an absolute scarcity of food, however, but to the more complex issues of who grows food and how and where it is grown, how it is distributed, and finally, who has access to it. In this complicated web of causality, inequality is the outstanding driving force behind hunger. Misuse and over-exploitation of natural resources are other central factors underlying food gaps. Any technological policy for rural and agricultural development, then, must be judged on, among other factors, whether it tends to increase or decrease inequity in the distribution of and access to resources and food, and whether it ensures sustainability of resource use.

Proponents of a ‘second’ Green Revolution (GRII) generally argue that scarcity and low agricultural productivity cause food insecurity and will also aggravate global hunger in the future. Those holding this perspective usually believe that ‘overpopulation’ and food scarcity cause hunger, and likewise, dwell on aggregate global food production/consumption figures to justify GRII, but seldom look at distribution and disparities at the local or regional level. Therefore they propose a new wave of agricultural intensification based on stepped-up fertiliser and pesticide use in Africa and parts of Latin America, bioengineered crop varieties, and trade policies that would allow Northern food supplies to cover for any ‘food gaps’ remaining in the South after GRII. Likewise, they usually promote the agroindustrial model that stresses uniformity, and standardised technologies for large-scale high-input and mechanised systems, aimed at maximising yields of commercial crops, to fuel a global food system.

Yet, evidence suggests that this GR approach is unlikely to be the appropriate strategy to end hunger. Serious concerns have been raised by economic analysts, NGOs (non-governmental organisations), and farmers in many parts of the world about the validity of this approach. Earlier versions of the GR technological package have in many cases generated soil, pest and weed problems, sometimes leading to long-term yield decline. Bioengineering produces varieties that are not locally adapted and must be purchased by cash-strapped farmers. The widespread introduction of such varieties poses environmental risks and can reduce the genetic diversity of food crops and varieties, elevating risk and food insecurity for farmers in many areas. Dumping of Northern food surpluses is already a key factor depressing productivity in the South. The GRII emphasis on capital-intensive, off-farm, chemical inputs is likely to both reinforce yield levelling or decline, and generate further inequity, thus making it a less than ideal policy package for attacking hunger.

Advantages of agroecology

In contrast, the agroecological approach favoured by increasing numbers of farmers, NGOs, and analysts around the world offers several advantages. First, it is an alternative path to agricultural productivity or intensification that relies on local farming knowledge and techniques adjusted to different local conditions, management of diverse on-farm resources and inputs, and incorporation of contemporary scientific understanding of biological principles and resources in farming systems. Second, it offers the only practical way to actually restore agricultural lands that have been degraded by conventional agronomic practices. Third, it offers an environmentally sound and affordable way for smallholders to sustainably intensify production in marginal areas. Finally, it has the potential to reverse the anti-peasant biases inherent in strategies that emphasise purchased inputs and machinery, valuing instead the assets that small farmers already possess, including local knowledge and the low opportunity costs for labour that prevail in the regions where they live. Thus it is an approach that is likely to decrease, rather than exacerbate, inequality, and also enhance sustainability.


Agroecology is a scientific discipline that defines, classifies and studies agricultural systems from an ecological and socioeconomic perspective. It is also considered the scientific foundation of sustainable agriculture as it provides ecological concepts and principles for the analysis, design and management of productive, resource-conserving agricultural systems. Agroecology integrates indigenous knowledge with modern technical knowledge to arrive at environmentally and socially sensitive approaches to agriculture, encompassing not only production goals, but also social equity and ecological sustainability of the system. In contrast to the conventional agronomic approach that focuses on the spread of packaged uniform technologies, agroecology emphasises vital principles such as biodiversity, recycling of nutrients, synergy and interaction among crops, animals, soil, etc., and regeneration and conservation of resources. The particular methods or technologies promoted by agroecologists build upon local skills and are adapted to local agroecological and socioeconomic conditions. The implementation of such agroecological principles within the context of a pro-poor, farmer-centred rural development strategy is essential for healthy, equitable, sustainable and productive systems.


Today there are thousands of examples where rural producers, in partnership with NGOs and other organisations, have promoted and implemented alternative, agroecological development projects which incorporate elements of both traditional knowledge and modern agricultural science, featuring resource-conserving yet highly productive systems such as polycultures, agroforestry, the integration of crops and livestock, etc.

There is enough evidence available today - despite the fact that researchers have paid scant attention to these systems - to suggest that these agroecological technologies promise to contribute to food security at many levels. Just how productive and sustainable they are is to some degree still an empirical question. But it is likely that the prevalence of similar systems among smallholders is a factor in the universally observed inverse relationship between farm size and production, whereby smaller farms make far more productive use of the land resources than do large farms. Yet, even medium- and large-scale producers are increasingly making use of the agroecological approach, recognising the advantages of these principles and techniques over conventional approaches.

Critics of such alternative production systems point to lower crop yields than in high-input conventional systems. Yet all too often it is precisely the emphasis on yield - a measure of the performance of a single crop - that blinds analysts to broader measures of sustainability and to the greater per-unit area productivity obtained in complex, integrated agroecological systems that feature many crop varieties together with animals and trees. There are also cases where even yields of single crops are higher in agroecological systems that have undergone the full conversion process.

Assessments of various initiatives in Africa, Asia and Latin America show that agroecological technologies can bring significant environmental and economic benefits to farmers and communities. If such experiences were to be scaled up, multiplied, extrapolated and supported in alternative policy scenarios, the gains in food security and environmental conservation would be substantial. In this article we summarise some cases from Latin America and Africa to explore the potential of the agroecological approach.

Stabilising the hillsides of Central America

Perhaps the major agricultural challenge in Latin America is to design cropping systems for hillside areas that are productive and also reduce erosion. Several organisations have taken on this challenge with initiatives that emphasise the stewardship of soil resources, utilisation of local resources, and inputs produced on-farm.

Since the mid-1980s, the private voluntary organisation World Neighbours has sponsored an agricultural development and training programme in Honduras to control erosion and restore the fertility of degraded soils. Soil conservation practices were introduced - such as drainage and contour ditches, grass barriers, and rock walls - and organic fertilisation methods were emphasised, such as chicken manure and intercropping with legumes. Programme yields tripled or quadrupled from 400 kilograms per hectare to 1,200-1,600 kilograms, depending on the farmer. This tripling in per-hectare grain production has ensured that the 1,200 families participating in the programme have ample grain supplies for the ensuing year. Subsequently COSECHA, a local NGO promoting farmer-to-farmer methodologies on soil conservation and agroecology, helped some 300 farmers experiment with terracing, cover crops and other new techniques. Half of them have already tripled their corn and bean yields; 35 have gone beyond staple production and are growing carrots, lettuce and other vegetables to sell in local markets.

Throughout Central America, CIDDICO and other NGOs have promoted the use of grain legumes as green manure, an inexpensive source of organic fertiliser to build up organic matter. Hundreds of farmers in the northern coast of Honduras are using velvet bean (Mucuna pruriens) with excellent results, including corn yields of about 3,000kg/ha, more than double the national average, erosion control, weed suppression and reduced land preparation costs.

The velvet beans produce nearly 30 t/ha of biomass per year, or about 90-100 kg of N/ha per year. Taking advantage of well-established farmer-to-farmer networks such as the campesino-a-campesino movement in Nicaragua and elsewhere, the spread of this simple technology has occurred rapidly.

In just one year more than 1,000 peasants recovered degraded land in the Nicaraguan San Juan watershed. Economic analyses of these projects indicate that farmers adopting cover cropping have lowered their utilisation of chemical fertilisers (from 1,900 kg/ha to 400 kg/ha) while increasing yields from 700 kg to 2,000 kg/ha, with production costs about 22% lower than for farmers using chemical fertilisers and monocultures.

Scientists and NGOs promoting slash/mulch systems based on the traditional tapado system, used on the Central American hillsides, have also reported increased maize yields (about 3,000 kg/ha) and considerable reduction in labour inputs as cover crops smother aggressive weeds, thus minimising the need for weeding. Another advantage is that drought-resistant mulch legumes such as Dolichos lablab provide good forage for livestock.

These kinds of agroecological approaches are currently being used on a relatively small percentage of land, but as their benefits are being recognised by farmers, they are spreading quickly. Such methods have strong potential and offer important advantages for other areas of Central America and beyond.

Agroecology in the Andean region

In Peru, NGOs have studied pre-Columbian technologies in search of solutions to contemporary problems of high-altitude farming. A fascinating example is the revival of an ingenious system of raised fields that evolved on the high plains of the Peruvian Andes about 3,000 years ago. According to archaeological evidence, these waru-warus, platforms of soil surrounded by ditches filled with water, were able to produce bumper crops despite floods, droughts and the killing frosts common at altitudes of nearly 4,000 metres.

In 1984, several NGOs and state agencies created the Projecto Interinstitucional de Rehabilitaci-n de Waru-warus (PIWA) to assist local farmers in reconstructing the ancient systems. The combination of raised beds and canals has proven to have important temperature moderation effects, extending the growing season and leading to higher productivity on the waru-warus, compared to chemically fertilised normal pampa soils. In the district of Huatta, reconstructed raised fields produced impressive harvests, exhibiting sustained potato yields of 8-14 t/ha/yr. These figures contrast favourably with the average Puno potato yields of 1-4 t/ha/yr. In Camjata, potato yields reached 13 t/ha/yr and quinoa yields reached 2t/ha/yr in waru-warus. 

Elsewhere in Peru, several NGOs in partnership with local government agencies have engaged in programmes to restore abandoned ancient terraces. For example, in Cajamarca, in 1983 EDAC-CIED together with peasant communities initiated an all-encompassing soil conservation project. Over 10 years they planted more than 550,000 trees and reconstructed about 850 ha of terraces and 173 ha of drainage and infiltration canals. The end result is about 1,124 ha of land under conservation measures (roughly 32% of the total arable land), benefiting 1,247 families (about 52% of the total in the area). Crop yields have improved significantly. For example, potato yields went from 5 t/ha to 8 t/ha and oca yields jumped from 3 to 8 t/ha. Enhanced crop production, fattening of cattle and raising of alpaca for wool, have increased the income of families from an average $108 per year in 1983 to more than $500 today.

In the Colca valley of southern Peru, PRAVTIR (Programa de Acondicionamiento Territorial y Vivienda Rural) sponsors terrace reconstruction by offering peasant communities low-interest loans or seeds and other inputs to restore large areas (up to 30 ha) of abandoned terraces. The terraces minimise risk in times of frost and/or drought, reduce soil loss, broaden cropping options because of the microclimate and hydraulic advantages of terraces, and improve productivity. First-year results from new bench terraces showed 43-65% increases in yields of potatoes, maize and barley, compared to these crops grown on sloping fields.

Table 1: Performance of traditional, modern and alternative potato-based production systems in Bolivia

Potato yields (t/ha) 9.2 17.6 11.4
Chemical fertilizer (N kg/ha + P2O5 kg/ha) 0.0 80 + 120 0.0
Lupine biomass (t/ha) 0.0 0.0 1.53
Energy efficiency (output/input) 15.7 4.8 30.5
Net income per invested Boliviano (Bs) 6.21 9.4 9.9

Source: Rist, S. 1992.Ecologia, economia y tecnologias campesinas. RULTER 10:205-227

The native legume Lupinus mutabilis is used as a rotational or associated crop on the terraces; it fixes nitrogen, which is available to companion crops, minimising fertiliser needs and increasing production. As shown in Table 1, though yields are greater in chemically fertilised and machinery-prepared potato fields, energy costs are higher and net economic benefits are not necessarily greater than under the agroecological system. Surveys indicate that farmers prefer this alternative system as it optimises the use of scarce resources, labour and available capital, and is accessible to even poor producers. These kinds of methods are being scaled up and multiplied, showing great potential for improvements in productivity and sustainable food security throughout the region.

Integrated production systems

A number of NGOs promote the integrated use of a variety of management technologies and practices. The emphasis is on diversified farms in which each component of the farming system biologically reinforces the other components, for instance, where wastes from one component become inputs to another.

Since 1980, CET, a Chilean NGO, has engaged in a rural development programme aimed at helping peasants reach year-round food self-sufficiency while rebuilding the productive capacity of their small landholdings. The approach has been to set up several 0.5-ha model farms, which consist of a spatial and temporal rotational sequence of forage and row crops, vegetables, forest and fruit trees, and animals.

Components are chosen according to crop or animal nutritional contributions to subsequent rotational steps, their adaptation to local agroclimatic conditions, local peasant consumption patterns and, finally, market opportunities. Most vegetables are grown in heavily composted raised beds located in the garden section, each of which can yield up to 83 kg of fresh vegetables per month, a considerable improvement on the 20-30 kg produced in spontaneous gardens tended around households. The rest of the 200-square-metre area surrounding the house is used as an orchard, and for animals (cows, hens, rabbits and langstroth beehives).

Vegetables, cereals, legumes and forage plants are produced in a six-year rotational system within a small area adjacent to the garden. Relatively constant production is achieved (about 6 tons per year of useful biomass from 13 different crop species) by dividing the land into as many small fields of fairly equal productive capacity as there are years in the rotation. The rotation is designed to produce the maximum variety of basic crops in six plots, taking advantage of the soil-restoring properties and biological control features of the rotation.

Over the years, soil fertility in the original demonstration farm has improved, and no serious pest or disease problems have appeared. Fruit trees in the orchard and fencerows, as well as forage crops, are highly productive. Milk and egg production far exceeds that on conventional farms. A nutritional analysis of the system based on its key components shows that for a typical family it produces a 250% surplus of protein, 80% and 550% surpluses of vitamins A and C respectively, and a 330% surplus of calcium. A household economic analysis indicates that the balance between selling surpluses and buying preferred items provides a net income beyond consumption of US$790. If all of the farm output were sold at wholesale prices, the family could generate a monthly net income 1.5 times greater than the monthly legal minimum wage in Chile, while dedicating only a relatively few hours per week to the farm. The time freed up is used by farmers for other on-farm or off-farm income-generating activities.

The Cuban experience

In Cuba, the Asociaci-n Cubana de Agricultura Org‡nica (ACAO), a non-governmental organisation formed by scientists, farmers and extension personnel, has played a pioneering role in promoting alternative production modules. In 1995 ACAO helped establish three integrated farming systems (called ‘agroecological lighthouses’) in cooperatives (CPAs) in the province of Havana. After the first six months, all three CPAs had incorporated agroecological innovations (i.e. tree integration, planned crop rotation, polycultures, green manures, etc.) to varying degrees, which, with time, have led to enhancement of production and biodiversity, and improvement in soil quality, especially organic matter content.

Several polycultures, such as cassava-beans-maize, cassava-tomato-maize, and sweet potato-maize, were tested in the CPAs. Productivity evaluation of these polycultures indicates 2.82, 2.17 and 1.45 times greater productivity than monocultures respectively. The use of Crotalaria juncea and Vigna unguiculata as green manure has ensured a production of squash equivalent to that obtainable by applying 175 kg/ha of urea. In addition, such legumes improved the physical and chemical characteristics of the soil and effectively broke the life cycles of insect pests such as the sweet potato weevil.

At the Cuban Instituto de Investigaciones de Pastos, several agroecological modules with various proportions of the farm area devoted to agriculture and animal production were established. Monitoring of production and efficiencies of a 75% pasture/25% crop module reveals that total production increases over time, and that energy and labour inputs decrease as the biological structuring of the system begins to sponsor the productivity of the agroecosystem. Total biomass production increased from 4.4 to 5.1 t/ha after three years of integrated management. Energy inputs decreased, which resulted in enhanced energy efficiency (from 4.4 to 9.5) (Table 2). Human labour demands for management also decreased over time. Such models have been promoted extensively through field days and farmers’ cross-visits. Similar results have been obtained by ICLARM researchers in the Philippines, where integrated rice-based systems with livestock, aquaculture, tree and vegetable components have proven to be productive, efficient and profitable, given labour availability and secure tenure.

In the African context, positive results from agroecological approaches have also been achieved. In Senegal, for example, the Senegal Regenerative Agriculture Centre is working to promote sustainable agriculture based on soil regeneration for small-scale farmers who have suffered from soil degradation. The cropping system is a millet-groundnut rotation, and legumes are intercropped with cereals. Compost is also being used to restore soil fertility. Cows, goats and sheep are usually kept by each household, and their manure is collected for the compost mixture. This project is operating in 11 villages, with active farmer participation. Results show that farmers can obtain an increase in millet grain of more than 400 kilograms per hectare if they put on at least 2 tonnes of compost. Similar yield increases were achieved with chemical fertilisers, but the cost-benefit ratio was less favourable.

Table 2: Productivity and efficiency of an integrated production system in Cuba (75% of the area devoted to pasture and 25% to crops)

Productive Parameters 1st Year 2nd Year 3rd Year
Area (ha) 1 1 1
Total production (t/ha) 4.4 4.9 5.1
Energy produced (Mcal/ha) 3797 3611 4885
Protein produced (kg/ha) 168 115 151
No.of people fed by one hectare 4 3.5 4.8
Inputs (energy expenditures, Mcal)      
Human labour 569 392 359
Animal work 16.8 16.8 18.8
Tractor energy 277.3 162.2 138.6
Energy efficiency (output/input) 4.4 8.8 9.5

Source: SANE, 1998.Farmers, lighthouses and NGOs:learning from 3 years of field activities, Berkeley, CA

In Tanzania, a Soil Erosion Control and Agroforestry project was initiated in 1980 in the Lushoto district. It included planting of perennial grass along contours to alleviate soil erosion and promote soil regeneration, as well as use of contour strips of trees, shrubs, and creeping legumes. The combination of these integrated methods reduced erosion by an average of 25%, and improved soil health. Tree species are also valuable for fodder. Total yields per hectare increased by 64% for areas with grass strips, and 87% for areas with contours. Gross marginal returns were 74% higher in the contour systems than under conventional approaches. These practices are being adopted by hundreds of people in this district, and offer promising alternatives for many other similar farming areas.

Current experiences in Ethiopia also show the importance of respecting and upholding agroecological principles. In this country, as in other African nations, there have been heavy pressures to promote GRII technologies, particularly through the widespread imposition of uniform wheat and maize varieties, and a technology package policy that requires farmers to buy fertilisers and other inputs. However, local people and government and NGO officials have opposed this model, recognising the problems and risks it entails, and they have defended and upheld the use of their diverse valuable local varieties of teff, sorghum, millet, and other grains that provide food security for the people. They have also worked on revival and ŌrescuingÕ of local seed varieties in community-based seedbanks, and promote integration of diverse sustainable farming practices in food security efforts.

These examples offer evidence of positive results, and also indicate increasing adoption and spread of the methods, as farmers realise their benefits for food security and sustained production for the market as well. In many parts of the world there is great potential for even wider application of these agroecological approaches.


Throughout the developing world Š in addition to the examples summarised above Š there are thousands of experiences of sustainable agriculture implemented at the local level by farmer organisations, NGOs, and other agencies. These experiences demonstrate the feasibility of intensifying production, regenerating and preserving soils, and maintaining biodiversity, based on agroecological technologies and locally available resources. In fact, data from documented cases show that when correctly managed, agroecological systems:

* exhibit more stable levels of total production per unit area over time,

* produce economically favourable rates of return, in both energetic and monetary terms,

* provide a return to labour and other inputs sufficient to provide an acceptable livelihood to small farmers and their families,

* ensure soil protection and conservation and enhance agro-biodiversity.

The combination of stable and diverse production with relatively high levels of production, internally generated and recycled inputs and nutrients, favourable energy input/output ratios and articulation of both subsistence and surplus for market production, is a clear indication of what the agroecological strategy of intensification can achieve. This approach also enables farmers to reduce dependency on external capital-intensive inputs, to take advantage of local resources, and to avoid the vulnerability associated with monocultural production systems. As such, it is a more equitable and sustainable strategy than the conventional GR approach. These experiences show direct improvements for household food security and livelihoods. The values of such an approach are also being recognised and shown by scientists/researchers in the science of agroecology and its applications. Even modern commercial agriculture enterprises which have become tired of the high costs and constraints of the conventional chemical-oriented approach are now realising that the ‘state of the art’ in achieving success in farming requires significant changes, to better understand, respect, uphold and enhance agroecological principles and biological limitations/capacities. As we enter the 21st century, agriculture should take on a new orientation or paradigm to achieve win-win solutions; this orientation should be ecologically and socially oriented, knowledge-based, and farmer-friendly. A major question often asked is: why hasn’t this agroecological approach spread more rapidly in recent decades? A major explanation is that powerful economic/corporate and institutional interests have backed R&D for the conventional GR agroindustrial approach, while R&D for agroecology and sustainable approaches has been largely ignored or even ostracised. Only in recent years has there been growing realisation of the advantages of these alternatives.

Since there is increasing evidence and awareness about the advantages of agroecological alternatives, how can this approach and associated technologies be multiplied and adopted more widely and consistently, worldwide? Clearly, a technological or ecological approach is not enough. Major changes must be made in policies, institutions, and methods of R&D to ensure that these agroecological alternatives are adopted, made accessible equitably and broadly, and multiplied, so that we can realise their full benefit in terms of food security.

The challenge is to increase investment and research into this strategy, and to scale up projects that have already proven successful, thereby generating a meaningful impact on the income, food security and environmental integrity of the world’s population, especially the millions of poor farmers yet untouched by modern agricultural technology. Existing subsidies and policy incentives for conventional chemical approaches must be dismantled, and institutional structures and partnerships and educational processes must change to enable this agroecological approach to blossom. In addition, participatory, farmer-friendly methods of technology development must be incorporated, ensuring that women, men, elders, and marginalised poor farmers or labour groups are included in the development of alternatives. If we fail to seize this opportunity, the existing cases will remain as ‘islands of success’ in a sea of deprivation, merely living testimonies to the potential of the ‘path not taken’ to feed the rural poor. On the other hand, if we go forward to widely support and develop an agroecological approach, humanity can benefit from its potential to address the inequity, hunger and environmental degradation that so often accompany high-input, energy-intensive, corporate-style agriculture.