Agroecology is the study of ecological processes applied to agricultural production systems. Bringing ecological principles to bear in agroecosystems can suggest novel management approaches that would not otherwise be considered. The term is often used imprecisely and may refer to “a science, a movement, a practice”. Agroecologists study a variety of agroecosystems. The field of agroecology is not associated with any one particular method of farming, whether it be organic, integrated, or conventional, intensive or extensive. However, it has much more in common with organic and integrated farming.
Agroecologists do not unanimously oppose technology or inputs in agriculture but instead assess how, when, and if technology can be used in conjunction with natural, social and human assets. Agroecology proposes a context- or site-specific manner of studying agroecosystems, and as such, it recognizes that there is no universal formula or recipe for the success and maximum well-being of an agroecosystem. Thus, agroecology is not defined by certain management practices, such as the use of natural enemies in place of insecticides, or polyculture in place of monoculture.
Instead, agroecologists may study questions related to the four system properties of agroecosystems: productivity, stability, sustainability and equitability. As opposed to disciplines that are concerned with only one or some of these properties, agroecologists see all four properties as interconnected and integral to the success of an agroecosystem.
Agroecologists study these four properties through an interdisciplinary lens, using natural sciences to understand elements of agroecosystems such as soil properties and plant-insect interactions, as well as using social sciences to understand the effects of farming practices on rural communities, economic constraints to developing new production methods, or cultural factors determining farming practices.
Agroecology as a set of agricultural practices
Agroecology provides primarily agricultural production systems based on processes and ecosystem function while industrial agriculture after the agricultural revolution or the Green Revolution thinks production from inputs. For C. Dupraz, agriculture could evolve in the medium or long term, moving from a logic of land use and other natural resources to a logic of “management of cultivated ecosystems”.
Prescriptive advice, ie the recommendation of “turnkey” agricultural practices, is problematic in agroecology, because of the characteristics of the organisms that are at the origin of ecosystem services: lack of knowledge about behavior organisms in agroecosystems; important effect of the local context on the activity and development of the organisms; difficulty in controlling organisms and the presence of unexpected or undesirable consequences; difficulty in assessing the effect of organisms on the functioning of the agroecosystem. In these conditions, with a lack of knowledge and the difficulty of assessing the consequences of decisions, adaptive management is often best suited. Adaptive management is an iterative learning process, which is based on constant monitoring of the agro-ecosystem to adapt agricultural practices to produce knowledge and reduce uncertainty.
Altieri proposes 5 principles to develop agroecological practices:
To allow the recycling of biomass and nutrients;
Maintain favorable soil conditions for plant growth by maintaining a sufficient level of organic matter in the soil;
Optimize the use of resources (water, soil, light, nutrients) and minimize their losses;
Increase the diversity of species and cultivated varieties, in space and time;
Promote positive interactions between the different organisms present in the agroecosystem.
The main agroecological practices are:
Increased biodiversity by avoiding monocultures that require energy inputs, pesticides and fertilizers. This includes the use of long rotations and associated crops, which make it possible to benefit from the facilitation or complementarity of the ecological niches of the different species (milpa, cereal-legume associations, Creole gardens…).
Tillage that respects its structure and maintains populations of various microorganisms and animals in the soil horizons. An almost permanent plant cover is sought to limit erosion and structure the soil. Techniques such as no-till or mulch are encouraged.
The fertilization obtained using green manure to compost or digestate. The objective is to maintain a high level of humus that ensures sustainable fertility and ensures a more regular water supply. These means, often inexpensive, are accessible to the poorest farmers. The agroforestry can be part of this process as shown by practical experience using Gliricidia septum.
Natural phytosanitary treatments, minimized, biodegradable and traditionally used in pest control. Methods such as push-pull are encouraged and the search for ecological balances using associated crops, service plants or by maintaining refuge zones at the edge of plots is sought, in order to disadvantage pests and favor the auxiliaries of the cultures. They are part of the biological control by conservation. Allelopathic phenomena may also be favored.
The presence of pathogen and soil pest antagonists may be favored, as well as the development of soil suppressivity.
The use of plants as a physical barrier to pest movement, such as Crotalaria juncea, used against Bemisia tabaci.
The biological control by flood releases or acclimatization may also be used.
The selection of varieties most suitable for cultivated land, locally reproducible local species that allow true autonomy.
Economics and optimization of water consumption and irrigation through a better understanding of the land / water balance.
The source of mechanical or animal energy to avoid the waste of energy and expensive equipment, without denying progress but adjusting it to realities.
The facilities to fight against the erosion of surfaces (bunds, microbarrings, filter dikes) and use the rainwater, recharge the water tables.
The agroforestry can be used to diversify production, regulate water flow, possibly fix nitrogen if the trees are legumes and promote auxiliary culture.
A better coupling of livestock with crop production makes it possible to diversify production, to develop areas with spontaneous vegetation (heaths, steppes, permanent meadows, meadow orchards, summer pastures…) to valorize crop residues, waste human nutrition and livestock effluents and improve soil fertility (perennial forage crops, nitrogen-fixing or high biomass production plants, use of manure as fertilizer, allowing fertility transfer). Animals can also provide a work force and a means of transport.
Hedgerows for the protection of cultivated land.
Reforestation of unused land to produce fuel sources, natural pharmacopoeia, arts and crafts, food and feed, soil regeneration.
Rehabilitation of traditional know-how and ecological economic management.
Pedagogy adapted to actors in the field.
The agro-ecological infrastructure provide many ecosystem services and amenities, in terms of landscape, protection of soil, water and air, habitat for species some of which are agricultural aids). They play a major role in maintaining or restoring the biological connectivity of the rural green and blue weave. They can contribute to improving production by reducing the need for inputs chemical and energy.
Among them, the association CDA (Agroecology Development Center) works for the progress and development of agroecology in France. It works in close collaboration with farmers but also agribusiness companies, public actors and professional agricultural organizations.
Rural development in poor countries
Agroecology represents a real alternative to so- called conventional (industrial) production systems in developing countries. Indeed, by focusing on the sustainable balance of the soil-crop system, it allows for a reduction in input inputs over the long term. For Olivier De Schutter, Special Rapporteur on the right to food (in) the Council for Human Rights at the United Nations, “We must change course, the old recipes are no longer worth today. Support policies for agriculture aimed to direct agriculture towards industrial agriculture; they must now move towards agro-ecology wherever possible “.
The consideration of this balance also results in improved resilience of crops to difficult conditions episodes of drought, pressure from weeds, poor soils, common conditions in developing countries, particularly on the African continent.
Example: The Rural Income Promotion Program or PPRR, an IFAD project in Madagascar, supports farmers who have chosen to apply the principles of agroecology on their farms through microproject financing (see the video testimonial Malagasy peasant in the external links).
Some international solidarity associations have chosen to put agroecology as a vector for local development. For Patrice Burger, Director of CARI and Representative of Civil Society in the framework of the United Nations Convention to Combat Desertification (UNCCD), “agro-ecology, beyond a set of techniques, must be considered as a real step “.
Revitalization of cultivated soils
According to some scientists, the soils in many countries of the world, would be degraded. Overuse of pesticides and intensive cultivation are the causes.
To prevent this degradation of soils, compost and manure can be spread on soils, but chemicals must be limited. Finally, some modern varieties, especially hybrids, are more fragile than traditional varieties, which require less irrigation. These, well associated with other plants or trees, vegetables, fruits or condiments, are perfectly profitable and their growth is even stronger than hybrids. The need for pesticides and irrigation are so much lower.
Agroecology as a scientific discipline
Agroecology is also an emerging scientific discipline. Its purpose is the study of agroecosystems and the application of knowledge of ecology to agriculture.
Miguel Altieri of the University of Berkeley is a pioneer of this discipline and is regularly solicited by UNEP. He proposes this definition (1995): “Agroecology is the science of managing natural resources for the poorest in the face of an unfavorable environment. This science, of a biophysical nature in the broad sense, thus focuses on the accumulation of knowledge about the functioning of (cultivated) ecosystems. It leads to the design, creation and adaptation in the participatory form of complex and productive production systems that are attractive in spite of an unfavorable environment and despite a very weak recourse toinputs… ”
Agroecology research can be carried out at different scales: plot, farm, landscape, agrarian system. Francis, in 2003, proposes a definition of agroecology at the scale of agrarian systems or food systems: “the integrative study of the ecology of the entire food system, including the ecological, economic and social dimensions”. Agroecology is also characterized by its transdisciplinary approach (including agronomy, ecology, human and social sciences), by taking into account local knowledge and by analyzing systems.
Because of the multiplicity of research topics that can be part of agroecology and therefore emerging epistemological differences, some authors such as Van Dam et al. (2012) suggest distinguishing 3 branches within scientific agroecology:
systemic agroecology, which deals with the “bio-technical” dimension, largely based on ecology, for example, the work of Miguel Altieri was included in this branch as a first step,
human agroecology to account for the social organizations involved in agroecosystems, the works of Victor M. Toledo or those of Eduardo Sevilla Guzman are a good illustration of what this branch can produce,
Finally, the political agroecology intends to approach the relation between the measures, political configurations and the agroecosystems, in relation with the social systems to which we refer above, for this last branch, the works of Manuel Luis Gonzalez de Molina Navarro (MG de Molina) are essential references.
Agroecology as Science
As a science, agroecology is part of ecology or landscape ecology. It deals with the ecological conditions and processes of agroecosystems and the ecosystem complex agricultural landscape as a whole. Agroecology not only takes account of the ecosystems that are directly subject to agricultural use, such as cropland and grassland, but also the functionally linked more natural ecosystems such as forests and bogs and their indirect influence by agriculture (eg via atmospheric substance inputs or lateral material transfer).,
In the sense of basic scientific research, agroecology deals with the control variables of the biodiversity of agroecosystems and the agricultural landscape. Taking into account the biotic hierarchical levels (genes, species, populations, communities), it considers individual organisms, groups of organisms or the largest possible proportion of the totality of all organisms and their interrelationships (eg trophic interactions, competition, reciprocal benefits) and investigated especially the relationships between site properties, Land Use and Biodiversity, as well as the Significance of Spatial Patterns and Usage Dynamics for Biodiversity. In the sense of applied scientific research, agroecology aims to assess the agricultural nature of agricultural land use and support the development of ecologically sustainable agricultural use concepts.
The methods of agroecological research vary with the respective ecosystems and groups of organisms studied and, with site surveys, aerial and satellite image interpretations, applications of geographic information systems and ecological modeling, show proximity to adjacent scientific disciplines such as ecological site knowledge and landscape ecology.
Agroecology is taught at universities with different emphases in terms of subject area, subject area, study program or interdisciplinary program. The field of agroecology is located in different disciplines (eg biology, geography, agricultural sciences).
Agroecologists do not always agree about what agroecology is or should be in the long-term. Different definitions of the term agroecology can be distinguished largely by the specificity with which one defines the term “ecology”, as well as the term’s potential political connotations. Definitions of agroecology, therefore, may be first grouped according to the specific contexts within which they situate agriculture. Agroecology is defined by the OECD as “the study of the relation of agricultural crops and environment.” This definition refers to the “-ecology” part of “agroecology” narrowly as the natural environment. Following this definition, an agroecologist would study agriculture’s various relationships with soil health, water quality, air quality, meso- and micro-fauna, surrounding flora, environmental toxins, and other environmental contexts.
A more common definition of the word can be taken from Dalgaard et al., who refer to agroecology as the study of the interactions between plants, animals, humans and the environment within agricultural systems. Consequently, agroecology is inherently multidisciplinary, including factors from agronomy, ecology, sociology, economics and related disciplines. In this case, the “-ecology” portion of “agroecology is defined broadly to include social, cultural, and economic contexts as well. Francis et al. also expand the definition in the same way, but put more emphasis on the notion of food systems.
Agroecology is also defined differently according to geographic location. In the global south, the term often carries overtly political connotations. Such political definitions of the term usually ascribe to it the goals of social and economic justice; special attention, in this case, is often paid to the traditional farming knowledge of indigenous populations. North American and European uses of the term sometimes avoid the inclusion of such overtly political goals. In these cases, agroecology is seen more strictly as a scientific discipline with less specific social goals.
This approach is derived from the science of ecology primarily based on population ecology, which over the past three decades has been displacing the ecosystems biology of Odum. Buttel explains the main difference between the two categories, saying that “the application of population ecology to agroecology involves the primacy not only of analyzing agroecosystems from the perspective of the population dynamics of their constituent species, and their relationships to climate and biogeochemistry, but also there is a major emphasis placed on the role of genetics.”
This concept was proposed by political ecologist Josep Garí to recognise and uphold the integrated agro-ecological practices of many indigenous peoples, who simultaneously and sustainably safeguard, manage and use ecosystems for agricultural, food, biodiversity and cultural purposes at the same time. Indigenous agroecologies are not systems and practices halted in time, but keep co-evolving with new knowledge and resources, such as that provided by development projects, research initiatives and agro-biodiversity exchanges. In fact, the first agro-ecologists were indigenous peoples that advocated development policies and programmes to support their systems, rather than replacing them.
Rather than viewing agroecology as a subset of agriculture, Wojtkowski takes a more encompassing perspective. In this, natural ecology and agroecology are the major headings under ecology. Natural ecology is the study of organisms as they interact with and within natural environments. Correspondingly, agroecology is the basis for the land-use sciences. Here humans are the primary governing force for organisms within planned and managed, mostly terrestrial, environments.
As key headings, natural ecology and agroecology provide the theoretical base for their respective sciences. These theoretical bases overlap but differ in a major way. Economics has no role in the functioning of natural ecosystems whereas economics sets direction and purpose in agroecology.
Under agroecology are the three land-use sciences, agriculture, forestry, and agroforestry. Although these use their plant components in different ways, they share the same theoretical core.
Beyond this, the land-use sciences further subdivide. The subheadings include agronomy, organic farming, traditional agriculture, permaculture, and silviculture. Within this system of subdivisions, agroecology is philosophically neutral. The importance lies in providing a theoretical base hitherto lacking in the land-use sciences. This allows progress in biocomplex agroecosystems including the multi-species plantations of forestry and agroforestry.
To arrive at a point of view about a particular way of farming, an agroecologist would first seek to understand the contexts in which the farm(s) is(are) involved. Each farm may be inserted in a unique combination of factors or contexts. Each farmer may have their own premises about the meanings of an agricultural endeavor, and these meanings might be different from those of agroecologists. Generally, farmers seek a configuration that is viable in multiple contexts, such as family, financial, technical, political, logistical, market, environmental, spiritual. Agroecologists want to understand the behavior of those who seek livelihoods from plant and animal increase, acknowledging the organization and planning that is required to run a farm.
Views on organic and non-organic milk production
Because organic agriculture proclaims to sustain the health of soils, ecosystems, and people, it has much in common with Agroecology; this does not mean that Agroecology is synonymous with organic agriculture, nor that Agroecology views organic farming as the ‘right’ way of farming. Also, it is important to point out that there are large differences in organic standards among countries and certifying agencies.
Three of the main areas that agroecologists would look at in farms, would be: the environmental impacts, animal welfare issues, and the social aspects.
Environmental impacts caused by organic and non-organic milk production can vary significantly. For both cases, there are positive and negative environmental consequences.
Compared to conventional milk production, organic milk production tends to have lower eutrophication potential per ton of milk or per hectare of farmland, because it potentially reduces leaching of nitrates (NO3−) and phosphates (PO4−) due to lower fertilizer application rates. Because organic milk production reduces pesticides utilization, it increases land use per ton of milk due to decreased crop yields per hectare. Mainly due to the lower level of concentrates given to cows in organic herds, organic dairy farms generally produce less milk per cow than conventional dairy farms. Because of the increased use of roughage and the, on-average, lower milk production level per cow, some research has connected organic milk production with increases in the emission of methane.
Animal welfare issues vary among dairy farms and are not necessarily related to the way of producing milk (organically or conventionally).
A key component of animal welfare is freedom to perform their innate (natural) behavior, and this is stated in one of the basic principles of organic agriculture. Also, there are other aspects of animal welfare to be considered – such as freedom from hunger, thirst, discomfort, injury, fear, distress, disease and pain. Because organic standards require loose housing systems, adequate bedding, restrictions on the area of slatted floors, a minimum forage proportion in the ruminant diets, and tend to limit stocking densities both on pasture and in housing for dairy cows, they potentially promote good foot and hoof health. Some studies show lower incidence of placenta retention, milk fever, abomasums displacement and other diseases in organic than in conventional dairy herds. However, the level of infections by parasites in organically managed herds is generally higher than in conventional herds.
Social aspects of dairy enterprises include life quality of farmers, of farm labor, of rural and urban communities, and also includes public health.
Both organic and non-organic farms can have good and bad implications for the life quality of all the different people involved in that food chain. Issues like labor conditions, labor hours and labor rights, for instance, do not depend on the organic/non-organic characteristic of the farm; they can be more related to the socio-economical and cultural situations in which the farm is inserted, instead.
As for the public health or food safety concern, organic foods are intended to be healthy, free of contaminations and free from agents that could cause human diseases. Organic milk is meant to have no chemical residues to consumers, and the restrictions on the use of antibiotics and chemicals in organic food production has the purpose to accomplish this goal. Although dairy cows in both organic and conventional farming practices can be exposed to pathogens, it has been shown that, because antibiotics are not permitted as a preventative measure in organic practices, there are far fewer antibiotic resistant pathogens on organic farms. This dramatically increases the efficacy of antibiotics when/if they are necessary.
In an organic dairy farm, an agroecologist could evaluate the following:
Can the farm minimize environmental impacts and increase its level of sustainability, for instance by efficiently increasing the productivity of the animals to minimize waste of feed and of land use?
Are there ways to improve the health status of the herd (in the case of organics, by using biological controls, for instance)?
Does this way of farming sustain good quality of life for the farmers, their families, rural labor and communities involved?
Views on no-till farming
No-tillage is one of the components of conservation agriculture practices and is considered more environmental friendly than complete tillage. There is a general consensus that no-till can increase soils capacity of acting as a carbon sink, especially when combined with cover crops.
No-till can contribute to higher soil organic matter and organic carbon content in soils, though reports of no-effects of no-tillage in organic matter and organic carbon soil contents also exist, depending on environmental and crop conditions. In addition, no-till can indirectly reduce CO2 emissions by decreasing the use of fossil fuels.
Most crops can benefit from the practice of no-till, but not all crops are suitable for complete no-till agriculture. Crops that do not perform well when competing with other plants that grow in untilled soil in their early stages can be best grown by using other conservation tillage practices, like a combination of strip-till with no-till areas. Also, crops which harvestable portion grows underground can have better results with strip-tillage, mainly in soils which are hard for plant roots to penetrate into deeper layers to access water and nutrients.
The benefits provided by no-tillage to predators may lead to larger predator populations, which is a good way to control pests (biological control), but also can facilitate predation of the crop itself. In corn crops, for instance, predation by caterpillars can be higher in no-till than in conventional tillage fields.
In places with rigorous winter, untilled soil can take longer to warm and dry in spring, which may delay planting to less ideal dates. Another factor to be considered is that organic residue from the prior year’s crops lying on the surface of untilled fields can provide a favorable environment to pathogens, helping to increase the risk of transmitting diseases to the future crop. And because no-till farming provides good environment for pathogens, insects and weeds, it can lead farmers to a more intensive use of chemicals for pest control. Other disadvantages of no-till include underground rot, low soil temperatures and high moisture.
Based on the balance of these factors, and because each farm has different problems, agroecologists will not attest that only no-till or complete tillage is the right way of farming. Yet, these are not the only possible choices regarding soil preparation, since there are intermediate practices such as strip-till, mulch-till and ridge-till, all of them – just as no-till – categorized as conservation tillage. Agroecologists, then, will evaluate the need of different practices for the contexts in which each farm is inserted.
In a no-till system, an agroecologist could ask the following:
Can the farm minimize environmental impacts and increase its level of sustainability; for instance by efficiently increasing the productivity of the crops to minimize land use?
Does this way of farming sustain good quality of life for the farmers, their families, rural labor and rural communities involved?
The principles of agroecology are expressed differently depending on local ecological and social contexts.
Latin America’s experiences with North American Green Revolution agricultural techniques have opened space for agroecologists. Traditional or indigenous knowledge represents a wealth of possibility for agroecologists, including “exchange of wisdoms”. See Miguel Alteiri’s Enhancing the Productivity of Latin American Traditional Peasant Farming Systems Through an Agroecological Approach for information on agroecology in Latin America.
Agroecological techniques and knowledge played an important role in solving the severe food crisis in Cuba following the dissolution of the Soviet Union. As part of Cuba’s urban agricultural movement, agroecology is integral to production in Cuban organopónicos.
Historically, agroecology has had low traction in Africa, as governments, international organisations, extension services and farmers’ organisations tended to focus on issues of inputs and outputs as the defining factors to deal with recurrent food crises and chronic malnutrition in the continent. Agrocecology was only a minor proposal from a few, non-governmental, small-scale projects and a sort of “experimental” idea of the Farmer Field Schools programme.
In the early 2000s, when the AIDS pandemic was creating a major rural crisis across Africa, Josep Garí proposed FAO to consider an agroecological approach as the most effective way to empower farmers cope with the impacts of the AIDS pandemic on agriculture and food production: in particular, he proposed agro-biodiversity as a key resource and knowledge for farmers to address the labour and malnutrition crisis. The proposal was rapidly adopted by the Farmer Field Schools scheme across the world, and even presented and translated in China.
Most recently, agroecology has started to permeate projects and discourses on farming and natural-resource management in Africa. In 2011, the 1st encounter of agroecology trainers took place in Zimbabwe and issued the Shashe Declaration.
Most of the historical farming in Madagascar has been conducted by indigenous peoples. The French colonial period disturbed a very small percentage of land area, and even included some useful experiments in Sustainable forestry. Slash-and-burn techniques, a component of some shifting cultivation systems have been practised by natives in Madagascar for centuries. As of 2006 some of the major agricultural products from slash-and-burn methods are wood, charcoal and grass for Zebu grazing. These practices have taken perhaps the greatest toll on land fertility since the end of French rule, mainly due to overpopulation pressures.
Source from Wikipedia