Global agricultural production is already being affected by changes in rainfall and temperature thus compromising food security. Official statistics predict that small scale farmers in developing countries will be especially vulnerable to climate change because of their geographic exposure, low incomes, reliance on agriculture and limited capacity to seek alternative livelihoods.

Although it is true that extreme climatic events can severely impact small farmers, available data is just a gross approximation at understanding the heterogeneity of small scale agriculture, ignoring the myriad of strategies that thousands of small farmers have used, and still use, to deal with climatic variability.

Observations of agricultural performance after extreme climatic events reveal that resilience to climate disasters is closely linked to the level of on-farm biodiversity. Diversified farms with soils rich in organic matter reduce vulnerability and make farms more resilient in the long-term. Based on this evidence, various experts have suggested that reviving traditional management systems, combined with the use of agroecological principles, represents a robust path to enhancing the resilience of modern agricultural production.

Diverse farming systems

A study conducted in Central American hillsides after Hurricane Mitch showed that farmers using diversification practices (such as cover crops, intercropping and agroforestry) suffered less damage than their conventional monoculture neighbours. A survey of more than 1800 neighbouring ‘sustainable’ and ‘conventional’ farms in Nicaragua, Honduras and Guatemala, found that the ‘sustainable’ plots had between 20 to 40% more topsoil, greater soil moisture and less erosion, and also experienced lower economic losses than their conventional neighbours. Similarly in Chiapas, coffee systems exhibiting high levels of diversity of vegetation suffered less damage from farmers to produce various annual crops simultaneously and minimise risk. Data from 94 experiments on intercropping of sorghum and pigeon pea showed that for a particular ‘disaster’ level quoted, sole pigeon pea crop would fail one year in five, sole sorghum crop would fail one year in eight, but intercropping would fail only one year in 36. Thus intercropping exhibits greater yield stability and less productivity decline during drought than monocultures.

At the El Hatico farm, in Cauca, Colombia, a five story intensive silvo-pastoral system composed of a layer of grasses, Leucaena shrubs, medium-sized trees and a canopy of large trees has, over the past 18 years, increased its stocking rates to 4.3 dairy cows per hectare and its milk production by 130%, as well as completely eliminating the use of chemical fertilizers. 2009 was the driest year in El Hatico’s 40-year record, and the farmers saw a reduction of 25% in pasture biomass, yet the production of fodder remained constant throughout the year, neutralising the negative effects of drought on the whole system. Although the farm had to adjust its stocking rates, the farm’s milk production for 2009 was the highest on record, with a surprising 10% increase compared to the previous four years. Meanwhile, farmers in other parts of the country reported severe animal weight loss and high mortality rates due to starvation and thirst.

Intercropping enables farmers to produce various
crops simultaneously and minimise risk in the 
process.

Enhancing soil organic matter 

Adding large quantities of organic materials to the soil on a regular basis is a key strategy used by many agoecological farmers, and is especially relevant under dryland conditions. Increasing soil organic matter (SOM) enhances resilience by improving the soil’s water retention capacity, enhancing tolerance to drought, improving infiltration, and reducing the loss of soil particles through erosion after intense rains. In long-term trials measuring the relative water holding capacity of soils, diversified farming systems have shown a clear advantage over conventional farming systems. Studies show that as soil organic matter content increases from 0.5 to 3%, available water capacity can double.

At the same time, organically-rich soils usually contain symbiotic mycorrhizal fungi, such as vesicular arbuscular mycorrhizal (VAM) fungi, which are a key component of the soil microbiota, influencing plant growth and soil productivity. Of particular significance is the fact that plants colonised by VAM fungi usually exhibit significantly higher biomass and yields compared to non-mycorrhizal plants, under water stress conditions. Mechanisms that may explain VAM-induced drought tolerance, and increased water use efficiency involve both increased dehydration avoidance and dehydration tolerance.

Managing soil cover

Protecting the soil from erosion is also a fundamental strategy for enhancing resilience. Cover crop mulching, green manures and stubble mulching protects the soil surface with residues and inhibits drying of the soil. Mulching can also reduce wind speed by up to 99%, thereby significantly reducing losses due to evaporation. In addition, cover crop and weed residues can improve water penetration and decrease water runoff losses by two to six times.

The challenge is to identify the responses that are sustainable, and to upscale them

Throughout Central America, many NGOs have promoted the use of grain legumes as green manures, an inexpensive source of organic fertilizer and a way of building up organic matter. Hundreds of farmers along the northern coast of Honduras are using velvet bean (Mucuna pruriens) with excellent results, including corn yields of about 3 tonne/ha, more than double the national average. These beans produce nearly 30 tonne/ha of biomass per year, adding about 90 to 100 kg of nitrogen per hectare per year to the soil. The system diminishes drought stress, because the mulch layer left by Mucuna helps conserve water in the soil, making nutrients readily available in periods of major crop uptake.

Today, well over 125,000 farmers are using green manures and cover crops in Santa Catarina, Brazil. Hillside family farmers modified the conventional no-till system by leaving plant residues on the soil surface. They noticed a reduction in soil erosion levels, and also experienced lower fluctuations in soil moisture and temperature. These novel systems rely on mixtures for summer and winter cover cropping which leave a thick residue on which crops like corn, beans, wheat, onions or tomatoes are directly sown or planted, suffering very little weed interference during the growing season. During the 2008-2009 season, when there was a severe drought, conventional maize producers experienced an average yield loss of 50%, reaching productivity levels of 4.5 tonne/ha. However the producers who had switched to no-till agroecological practices experienced a loss of only 20%, confirming the greater resilience of these systems.

Building social resilience

Undoubtedly, crop diversification represents a viable long-term strategy for farmers experiencing erratic weather. More diverse agroecosystems are more resilient to extreme climatic events, thus significantly reducing farmers vulnerability. Adding copious amounts of organic matter into soils is particularly strategic when confronting droughts as SOM increases water holding capacity and biological activity which enhances water use efficiency. Managing cover crops and green manures protects soil from erosion but also adds biomass, which in turn contributes to increased levels of SOM.

Clearly, agroecological strategies that enhance the ecological resiliency of farming systems are a necessary, but not sufficient, condition to achieve sustainability. Social resilience, defined as the ability of groups or communities to adapt to environmental stresses, must go hand in hand with ecological resilience. To be resilient, rural societies must have the ability to buffer disturbance with agroecological methods adopted and disseminated through self-organisation and collective action. Reducing social vulnerability through the extension and consolidation of social networks, both locally and at regional scales, can further increase the resilience of agroecosystems. The vulnerability of farming communities depends on the development of the natural and social capital that gives farmers and their systems resilience against climatic (and other) shocks (see figure on page 39). This adaptive capacity resides in a set of social and agroecological conditions that influence the ability of individuals or groups, and their farms, to respond to climate change in a resilient manner. This capacity to respond to changes in environmental conditions exists to different degrees within communities but the responses are not always sustainable. The challenge is to identify the responses that are sustainable, and to upscale them, enhancing the reactive capacity of communities to deploy agroecological practices that allow farmers to resist and recover from climatic events. Social organisation strategies (solidarity networks, farmer to farmer exchanges, community food and seed saving, etc.) used by farmers to cope with the difficult circumstances imposed by such events, are key component of socio-ecological resilience.

Clara Ines Nicholls (nicholls@berkeley.edu) is the president of SOCLA, Sociedad Científica Latino Americana de Agroecología and Regional coordinator of REDAGRES, Red IberoAmericana de Agroecología para el Desarrollo de Sistemas Agrícolas Resilientes al Cambio Climático.

Miguel A. Altieri (agroeco3@berkeley.edu) is Professor of Agroecology at University of California, Berkeley.

This is an updated version of the article that was first published in Farming Matters 28.2 in June 2012.

References

Altieri, M.A. and C.I. Nicholls 2013 The adaptation and mitigation potential of traditional agriculture in a changing climate. Climatic Change. DOI 10.1007/s10584-013-0909-y Altieri, M.A., C.I. Nicholls, A Henao and M.Lana 2015 Agroecology and the design of climate change resilient farming systems. Agronomy for Sustainable Development. DOI 10.1007/s 13593-015-0285-2

Magdoff, F. and H. van Es. 2000. Bulding Soils for Better Crops. Sustainable Agriculture Network. Beltsville, M.A. 230 pp

Natarajan, M, and R.W. Willey, 1996. The effects of water stress on yields advantages of intercropping systems. Field Crops Research 13: 117-131

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For decades, Latin American agro-ecologists have advocated a radical transformation of the world’s agricultural systems, looking not only at the agronomic aspects but also at the social, political, cultural and economic forces that drive agricultural development. Rural movements such as Via Campesina have long argued that farmers need land to produce food for their own communities, and for this reason they advocate genuine access to and control over land, water and agrobiodiversity. SOCLA is convinced that the changes promoted by farmers and their organisations need to be complemented by a similar revolt within academic and research institutions.

SOCLA believes that incorporating the principles of agro-ecology (from plant health and soil ecology to land politics and food sovereignty) into the educational process is one way to correct the current agricultural educational deficiencies in our institutions. By focusing on the interface between agriculture, the social system and the global environment, agro-ecological thought can help design a more creative and integrated curriculum. This, in turn, can help students to develop new capacities, making them better prepared to face future challenges and to guide agriculture through a path that sustains productivity while conserving natural resources and biodiversity, in socially equitable, culturally plural and economically viable ways.

“There is no doubt that we need professionals who will look at yields and outputs, but in relation to the lack of opportunities in rural areas, equity and power issues, pollution and health, or land grabs. A programme like this one enormously helps us to reflect on what we know, and what we need to know, in order to improve agricultural production. We urgently need to develop new ways of ‘doing science’.
 
“I was first invited to join the group of lecturers in 2010, and every year I have presented what we have done and achieved in Cuba. I especially appreciate that all the students have a rich experience, and that we can work together on the basis of that experience. Every group is a new challenge, and every time I have enjoyed the discussions and the ideas that come from the groups. What I have liked most, however, is that working together gives me new insights and ideas. I am growing together with all the students.”
 
Fernando Funes Mozote lectures in both Medellin and Managua. Previously a researcher at Cuba’s Pasture and Forage Research Institute, he is, since December 2011, a farmer.

Ideas for new curricula

SOCLA’s doctoral programmes are made up of three modules, held in Medellin or Managua, each lasting a month, covering the scientific basis of agro-ecology (biodiversity, resiliency, etc.), sustainable rural development (traditional knowledge systems, rural movements, land reform) and research methods (indicators, experimental design). Training includes lectures by researchers such as Peter Rosset, Steve Gliessman and Eric Holt-Giménez, complemented with readings and group discussions, and presentations of written and oral reports. As it focuses on an “action learning” approach, the programme also involves farm internships. The internships are planed during term time, when all the students are together, but take place in the students’ home areas, where they work with local farmers and organisations. In preparation for their research, students are expected to carry out a thorough diagnosis, considering indicators for sustainability or resilience, and propose changes that will enhance farm stability in the face of external shocks. Research for a doctoral thesis must be conducted in the student’s country of origin and always involves looking at possible solutions to the key problems affecting rural livelihoods.

After graduation, students are expected to possess a strong theoretical background, with methodological, analytical and practical skills. We aim at graduates with the skills to decipher complex interactions and to design, manage and evaluate agro-ecosystems that are diverse and resilient. Graduates are expected to acknowledge the benefits of traditional forms of agriculture, and to be able to mobilise local skills, technologies and resources for endogenous development. An equally important aim is to develop skills to empower social groups, to propose enabling policies, and to systematise and evaluate local development experiences in order to set a scaling up process in motion.

Students and graduates

While the course in Nicaragua only started this year, a total of 45 students are part of the programme in Colombia, from 8 different countries. Most of them lecture at different universities, so it is expected that they will promote curricular changes in their own programmes by creating courses on agro-ecology and research along agro-ecological lines. Ph.D. students working in research institutions are expected to implement a research agenda that is tailored to the needs and circumstances of small-scale farmers, and that leads to alternatives to the industrial agriculture movement. Graduates from SOCLA’s agro-ecology doctorate will be active promoters of food sovereignty and the welfare of family farmers.

References

Altieri, M.A. and C.I. Nicholls, 2012. Agroecology: Scaling up for food sovereignty and resilience. Sustainable Agriculture Reviews 11: 23-37

Francis, C.A., 2008. Education in agroecology and integrated systems. Journal of Crop Improvement, 11: 21-43

Leon, T. and M.A. Altieri, 2010. Enseñanza, investigación y extensión en agroecología: La creación de un programa de doctorado latinoamericano de agroecología. In: Vertientes del pensamiento agroecológico. T. Leon and M.Altieri (eds). Universidad Nacional de Colombia, Bogotá.

Miguel A. Altieri serves as President of the Sociedad Científica LatinoAmericana de Agroecología (SOCLA). Clara I. Nicholls is the co-ordinator of the Latin American Doctoral Programme at Colombia’s Universidad de Antioquia. E-mail: agroeco3@berkeley.edu

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Little has been done to enhance the adaptability of industrial agriculture to changing and extreme weather events, except for a focus on “magic bullets” such as genetic modification, with crops that are expected to produce under stressful environments.

Almost no work has been conducted on designing management practices that enhance the resilience of monocultures to climate change. But there is ample evidence that agro-ecological designs and practices contribute enormously to this.

In fact, many studies reveal that small-scale farmers who follow agro-ecological practices cope with, and even prepare for, climate change, minimising crop failure. Results from various studies suggest that these practices provide a higher resistance to climate events, reduce vulnerability and make farms more sustainable in the long-term.

Based on this evidence, various experts have suggested that reviving traditional management systems, combined with the use of agro-ecologically principles, may represent the only viable and robust path to increasing the productivity, sustainability and resilience of agricultural production. In this paper we explore a number of ways in which these strategies can be implemented through the design and management of agro-ecosystems, allowing farmers to adopt a strategy that, in the end, provides more economic benefits.

Diverse farming systems

REDAGRES
The Red IberoAmericana de Agroecologia para el Desarrollo de Sistemas Agricolas Resilientes al Cambio Climatico, REDAGRES, is a network of scientists and researchers spread across 8 countries. Its objectives are to promote the exchange of knowledge and information related to agriculture and climate change. In addition to analysing the impact of climate change on agricultural production, REDAGRES places special emphasis on exploring different adaptation strategies to extreme climatic events, and applying agro-ecological principles to the design and scaling-up of agro-ecosystems that are resilient to climate change.

A few months ago, REDAGRES launched a two year project involving a survey of small-scale farming systems in selected regions of Latin America. The aim is to identify those systems that have withstood climatic events (recently or in the past), and understand their main features. The emerging principles are being shared with family farmers in neighbouring communities and others in the region via field days, cross-visits, short seminars and courses. It is also being used to develop a farmer-friendly manual that will explain how to assess the level of resilience of a farm, showing what to do to enhance this.

Detailed analyses of agricultural performance after extreme climatic events have revealed that resilience to climate disasters is closely linked to the level of on-farm biodiversity.

A survey conducted in Central American hillsides after Hurricane Mitch showed that farmers using diversification practices (such as cover crops, intercropping and agroforestry) suffered less damage than their conventional monoculture neighbours.

A survey of more than 1,800 neighbouring “sustainable” and “conventional” farms in Nicaragua, Honduras and Guatemala, found that the “sustainable” plots had between 20 to 40% more topsoil, greater soil moisture and less erosion, and also experienced lower economic losses than their conventional neighbours.

Similarly, those coffee farms in Mexico which exhibit high levels of complexity and plant diversity suffered less damage from Hurricane Stan. And forty days after Hurricane Ike hit Cuba in 2008, researchers found that diversified farms exhibited losses of 50%, compared to 90 or 100% in neighbouring monocultures. Likewise, agro-ecologically managed farms showed a faster recovery in their production than monoculture farms.

These are only a few examples that show how complex agro-ecosystems are able to adapt and resist the effects of climate change. Agroforestry systems have been shown to buffer crops from large fluctuations in temperature, thereby keeping the crops closer to their optimum conditions. More shaded coffee systems have shown to protect crops from low precipitation and reduced soil water availability. This is because the overstory reduces soil evaporation and the roots increase soil water infiltration.

At the same time, intercropping enables farmers to produce various crops simultaneously and minimise risk. Polycultures exhibit greater yield stability and less productivity declines during drought. A study of the effect of drought (Natarajan and Willey, 1986) on polycultures showed that intercropping is enormously successful. Quite interestingly, the rate of overyielding actually increased with water stress, showing that the relative differences in productivity between monocultures and polycultures increase with greater stress.

Another example is that of the intensive silvopastoral systems (ISS), which combine fodder shrubs planted at high densities, trees, palms, and pastures. High stocking levels are achieved through rotational grazing, which allows for the natural production of milk and meat in these systems. At the El Hatico farm, in Cauca, Colombia, a five story ISS composed of a layer of grasses, leucaena shrubs, medium-sized trees and a canopy of large trees has, over the past 18 years, increased its stocking rates to 4.3 dairy cows/ha and its milk production by 130%, as well as completely eliminating the use of chemical fertilizers. 2009 was the driest year in El Hatico’s 40-year record, and the farmers saw a reduction of 25% in pasture biomass, yet the production of fodder remained constant throughout the year, neutralising the negative effects of drought on the whole system.

In response to the extreme weather, the farm had to adjust its stocking rates. In spite of this, the farm’s milk production for 2009 was the highest on record, with a surprising 10% increase compared to the previous four years. Meanwhile, farmers in other parts of the country reported severe animal weight loss and high mortality rates due to starvation and thirst.

The combined benefits of water regulation, a favourable microclimate, biodiversity, and carbon stocks in such diversified farming systems, not only provide environmental goods and services for producers, but also greater resilience to climate change.

Enhancing soil organic matter

Crop productivity under dry land conditions is largely limited by the availability of water in the soil. The percentage of soil organic matter, or SOM content, is a reliable index of crop productivity in semiarid regions because SOM improves the soil’s ability to store and transmit air and water.

Adding large quantities of organic materials on a regular basis is another key strategy used by many ago-ecological farmers. SOM management is at the heart of all efforts to create healthy soils with a high level of biological activity and good physical and chemical characteristics.

Increasing the SOM enhances resilience by improving the soil’s water retention capacity, enhancing tolerance to drought, improving infiltration, and reducing the loss of soil particles through erosion after intense rains. SOM also improves surface soil aggregation, holding the soil particles tightly, protecting them against rain or windstorms.

At the same time, organically-rich soils usually contain symbiotic mycorrhizal fungi, such as arbuscular mycorrhizal (AM) fungi, which are a key component of the microbial populations influencing plant growth and soil productivity. AM fungi are important as they improve plant-water interactions, and thus increase resistance to drought. Some specific fungus-plant associations increase drought tolerance and are of great interest for areas affected by water deficits: AM fungi have been reported to increase nutrient uptake in water-stressed plants and to enable plants to use water more efficiently.

Protecting the soil from erosion is also a fundamental strategy for enhancing resilience. Cover crop mulching and green manures offer many advantages. Stubble mulching protects the soil surface with residues and inhibits drying of the soil. Mulching can also reduce wind speed by up to 99%, thereby significantly reducing losses due to evaporation. In addition, cover crop and weed residues can improve water penetration and decrease water runoff losses by 2 to 6 fold.

Throughout Central America, CIDDICO, Vecinos Mundiales and other NGOs have promoted the use of grain legumes as green manures, an inexpensive source of organic fertilizer and a way of building up organic matter.

Hundreds of farmers along the northern coast of Honduras are using velvet bean (Mucuna pruriens) with excellent results, including corn yields of about 3,000 kg/ha, more than double than national average. These beans produce nearly 30 tons/ha of biomass per year, adding about 90 to 100 kg of N/ha per year to the soil. The system diminishes drought stress, because the mulch layer left by Mucuna helps conserve water in the soil, making nutrients readily available in periods of major crop uptake.

Today, well over 125,000 farmers are using green manures and cover crops in Santa Catarina, Brazil. Hillside family farmers modified the conventional notill system by leaving plant residues on the soil surface. They noticed a reduction in soil erosion levels, and also experienced lower fluctuations in soil moisture and temperature. Repeated applications of fresh biomass improved the soil quality, minimised erosion and weed growth and improved crop performance. These novel systems rely on mixtures for summer and winter cover cropping which leave a thick residue on which crops like corn, beans, wheat, onions or tomatoes are directly sown or planted, suffering very little weed interference during the growing season.

During the 2008-2009 season, when there was a severe drought, conventional maize producers experienced an average yield loss of 50%, reaching productivity levels of 4,500 kilos per hectare. However the producers who had switched to no-till agro-ecological practices experienced a loss of only 20%, confirming the greater resilience of these systems.

Adding social resilience

More diverse plant communities are more resistant to disturbance and more resilient to environmental perturbations derived from extreme climatic events. Undoubtedly, crop diversification represents a viable long-term strategy for farmers experiencing erratic weather. The use of diversification within agricultural production systems can significantly reduce their vulnerability and protect their livelihoods. Farmers that use diversity as a crop management strategy usually add copious amounts of organic matter into their soils, further increasing water retention capacity. Managing cover crops and green manures improves the soil cover, protecting the soil from erosion, but also adds biomass, which in turn contributes to increased levels of SOM.

Such strategies to enhance the ecological resilience of farming systems are essential, but in themselves are not enough to achieve sustainability. Social resilience, defined as the ability of groups or communities to adapt to external social, political, or environmental stresses, must go hand in hand with ecological resilience. To be resilient, rural societies must have the ability to buffer disturbance with agro-ecological methods adopted and disseminated through self-organisation and collective action (Tompkins and Adger, 2004).

Reducing social vulnerability through the extension and consolidation of social networks, both locally and at regional scales, can further increase the resilience of agro-ecosystems. The vulnerability of farming communities depends on the development of the natural and social capital that gives farmers and their systems resilience against climatic (and other) shocks. This adaptive capacity resides in a set of social and agro-ecological conditions that influence the ability of individuals or groups, and their farms, to respond to climate change in a resilient manner. This capacity to respond to changes in environmental conditions exists to different degrees within communities but the responses are not always sustainable.

The challenge is to identify the responses that are sustainable and to upscale them, enhancing the reactive capacity of communities to deploy agro-ecological mechanisms that allow farmers to resist and recover from climatic events and reducing their vulnerability. Social organisation strategies (solidarity networks, exchange of food, etc.) used by farmers to cope with the difficult circumstances imposed by such events, are thus a key component of resilience.

Text: Clara Ines Nicholls and Miguel A. Altieri

Clara Ines Nicholls is the co-ordinator of REDAGRES, the Red IberoAmericana de Agroecología para el Desarrollo de Sistemas Agrícolas Resilientes al Cambio Climático.
E-mail: nicholls@berkeley.edu.

Miguel A. Altieri is the president of SOCLA, Sociedad Científica Latino Americana de Agroecología.
E-mail: agroeco3@berkeley.edu

References:

Lin, B.B., I. Perfecto and J. Vandermeer, 2008. Synergies between agricultural intensification and climate change could create surprising vulnerabilities for crops. BioScience 58, 847-854.
Natarajan, M, and R.W. Willey, 1996. The effects of water stress on yields advantages of intercropping systems. Field Crops Research 13: 117-131
Tompkins, E.L and W.N. Adger, 2004. Does adaptive management of natural resources enhance resilience to climate change? Ecology and Society 9(2): 10.

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