Summary
The use of inputs (chemical fertilizers, plant protection products) helps to develop agricultural productivity and maximize economic performance, but in return promotes environmental pollution and can affect human and animal health.
Today, reducing these harmful effects and preserving the environment are becoming a major concern worldwide.
The transition to sustainable agriculture has become a global and national socio-economic demand. The encouragement and support of the agroecology system becomes a national strategy.
Keywords: Inputs – agricultural productivity – pollution – sustainable agriculture – agroecology
The current agricultural and food system demonstrates every day its inability to adequately feed the population worldwide, this system becomes unable to maintain global food security especially in the face of high food demand due to population growth, diet change and climate change.
In Tunisia the agricultural sector remains of great economic and socio-political importance because of its contribution to the achievement of national objectives in terms of food security, the creation of employment income, regional balance and natural resource management, but the development of Tunisian agriculture is facing a number of structural constraints. Indeed, the agronomic model meets production stability constraints especially with climate change and the long drought period. The pressure on natural resources in particular water and soil becomes important day by day which leads to a degradation of the resilience of the ecosystem.
In short, agriculture in Tunisia suffers from weaknesses and threats related to ecological aspects, for example, the pressure exerted on irrigated perimeters resulting from mainly due to the low use of rainwater. Indeed, the irrigable area is around 410,000 ha, or 8% of the useful agricultural area. Semi- intensive irrigation and flood slopes constitute an estimated potential of 150. 00ha (MARH, 2016). This has led to intensive use and overexploitation of groundwater.
Similarly, Tunisia is experiencing significant soil degradation as a result of two types of hazards: the first is caused by natural factors (erosion, soil salinity), the second is caused by demographic development and urban development. The global crisis, climate change and the challenges facing the agricultural sector demand a shift towards a sustainable agricultural system that enhances human capital and the sound management of natural resources.
The transition from conventional agriculture to agroecology Conventional agriculture makes it possible to increase agricultural production considerably, the use of this agricultural system allows the producer to improve his income in view of the gradual increase in yields. Despite its high yields and high yields, conventional agriculture has faced many criticisms, both environmental (soil impoverishment, loss of biodiversity due to inputs and monoculture, pollution of water
table and soil) and social (dependence of producers on the chemical industry for the sale of fertilizers and plant protection products), the international scientific community is expanding to say that it has significant negative impacts on ecosystems, natural resources and biodiversity. The transition from the conventional model of agriculture to a sustainable model of agriculture based on natural functionality requires efforts, it is necessary to bring together farmers’ knowledge, science and technology, and it is also necessary to prepare an upstream environment that respects the new orientation from which the agroecological approach was born.
Agroecology is an integrated approach that simultaneously applies ecological and social concepts and principles to the design and management of food and agricultural systems. It aims to optimise interactions between plants, animals, humans and the environment, including the social aspects that need to be taken into account if a food system is to be sustainable and equitable (FAO, 2018).
Agroecology is also a method of agriculture with human capital, which intervenes mainly in the social justice of peasants and small farmers. Indeed, the first international symposium on agroecology in Albi France in 2008 would defend this value of social justice.
In Tunisia, the distribution of agro-ecological zones depends on the climate. Indeed, Tunisia is characterized mainly by a Mediterranean climate in the north, dry and hot summers and cool and humid winters on the east side, semi-arid climate in the interior of thecountry and Saharan climate in the south. Climatic variety allows for a wide variety of production (Table 1)
Agroecology: Objectives, Principles and Practices
1. Objectives
Agroecology makes it possible to develop a less polluting and environmentally friendly agricultural activity and to preserve the various natural resources (water, soil, energy . . . ). It also promotes optimal harmony between cultivation and livestock, which makes it possible to develop biodiversity on the one hand and to strengthen the local food system on the other.
Agroecology also aims to strengthen the producer-consumer link through the direct sale of agricultural products in short marketing channels.
2. Principles
Agroecology is based on 10 core components, which aim to support countries around the world in transforming their food and agricultural systems to achieve the Sustainable Development Goals (FAO, 2018)
Diversity:
Diversity is an important pillar of agroecology, improving food security by protecting natural resources. Diversity in agroecology includes several models, such as the vertical diversity that characterizes agroforestry and includes crops, shrubs, trees and livestock. Spatial diversity, which is characterised mainly by intercrops, combines complementary species in order to increase biodiversity. Temporal diversity, this type of diversity is enhanced by crop rotation, which allows for crop diversification over time, thereby maintaining food security. Biodiversity plays a major role in implementing ecological processes within agro-systems. It contains benefits in terms of production, nutrition, environment and socio-economic status. Research has shown that crop production is more productive when they are more diverse in terms of species. Co-creation and knowledge sharing Agroecology is an integrated approach that combines traditional knowledge of producers and scientific knowledge. This approach is based on a participatory and knowledge-sharing process that allows a better dissemination of agroecological practices, thus producing a sustainable axis for the concept of agroecology. Co-creation and knowledge sharing is part of the context in which local producers and scientists are mobilizing to engage policy makers in the transition to the agro-ecological system.
Synergy:
Consists of creating a link between the different components of the agroecological system (water-soil-trees-livestock. . . ). This synergy between the different components of the agroecological system allows for the proper management of natural resources, for example: the use of animal manure in soil fertilization. The synergy between the different components of the agro- ecological system ensures food security and the balance of the ecosystem.
Efficiency:
The practices of the agroecological system allow the proper use of natural resources and the valorization of free and abundant resources (renewable energy, nitrogen. . . ) by strengthening the biological process and reducing the use of external resources, which results in minimizing the negative effects on the environment and strengthening the autonomy of producers.
Recycling:
It is a phenomenon that allows to give a second life to a product. Recycling reduces the use of external resources and increases the autonomy of producers.
The benefits of recycling include:
– Independence from external resources
– Closing cycles and reducing waste
– Protect the environment and minimize the costs of using external resources
Resilience:
Agroecological systems are more resilient due to their resistance to extreme climatic conditions (drought, flooding, etc. ). Production system diversity and synergy management and recycling promote system resilience to climate change and socio-economic disruption. Agroecology improves socio-economic resilience by diversifying and strengthening producers by reducing their dependence on external inputs and their vulnerability to economic risks.
Human and social values:
In the agricultural sector, labour plays a vital role in food security and health, yet it remains economically marginalized and exposed to human rights violations (FAO, 2018). Integrating the agro-ecological approach helps to enhance human capital specifically for rural women working in the agricultural sector.
Agroecology plays a key role in equity, dignity and social well-being, which contributes to the Sustainable Development Goals (SDGs).
Indeed, the agroecological approach empowers farmers, producers and local people to overcome poverty, malnutrition and dependence on external inputs while promoting the human right to food and controlled access to natural resources.
Culture and food transitions:
Agroecology promotes a healthy diet and contributes to food security. Indeed, food is a pillar of human heritage. Agroecology aims to safeguard the culinary heritage and maintain food security. Responsible governance Agroecology is based on responsible governance mechanisms at different scales (local, national, global). Responsible governance facilitates the transition to sustainable food and agriculture systems (FAO, 2018). Such governance must be transparent and accessible in order to facilitate linkages with producers and ensure a smooth transition. Responsible governance mechanisms create an enabling environment that helps producers and farmers transform their systems. Circular and solidarity-based economy Agroecology aims to create short circuits between producers and consumers through a circular and solidarity-based economy that strengthens the development of the local market and therefore socio-economic development. The circular and solidarity-based economy makes it possible to re-establish the link between producers and consumers, which is important to promote local and solidarity-based circuits.
3. Agroecological practices
Good agroecological techniques are practical tools to improve sustainability in agriculture. They constitute a set of rules to be observed in the siting and management of crops or livestock in such a way as to optimise agricultural production, while at the same time reducing the risks associated with these practices both with regard to man (social and economic aspects) and with regard to the environment (ecological aspects). The agroecology system is based on a set of agricultural practices that have a significant impact on the preservation of the agro- system. These practices include:
The tillage
Soil is at the heart of agroecology, its productivity is determined mainly by its composition (sand, silt and clay), its drainage and its content of organic matter and nutrients, as well as by microbiological activity. Tillage influences the activity of microorganisms. In fact, the bacterial population develops by aeration and optimum moisture in the soils under tillage. In fact, a superficially worked soil offers good fertility, reduced erosion and run-off. Agroecology usually favours a minimum tillage of the soil, which requires the minimization of the use of machinery. The shift to tillage reduction techniques and the integration of diversification practices makes it possible to better maintain soil structure, stability and microbiological dynamics. In fact, the minimum tillage does not reverse the soil layers and the proportion of organic matter increases by the conservation of crop residues in the soil, which promotes soil fertilization. The physicochemical and hydrological properties of the soil are then improved, allowing soil fertility. In soils subjected to minimal tillage, the number of microorganisms increases in surface (0-10 cm) and decreases in depth (10-20 cm). Soil tillage requires a lot of energy (fuel consumption) and time, while minimal tillage reduces this demand, and consequently a decrease in CO2 emissions and air pollution. Soil fertility refers to its ability to sustainably produce high-quality crops. Fertile soil leads to complex interactions between physical (structure and aggregates), chemical (acidity, nutrient content) and biological (organic matter and microorganisms) fertility.
In agroecology, soil fertilization requires the use of organic fertilizers (manure – green manure – compost). The recycling and recovery of organic waste in soil fertilisation minimises the cost of inputs on the one hand and reduces the contamination of water by animal waste on the other.
Crop rotation
Crop rotation is a technique that involves alternating different crops (cereals, pulses, oilseeds. . . ) on the same parcel. This crop planning can take place over one year, but usually over several years, it is based on the alternation of an improvement crop (e. g. pulses) and an impoverished crop (e. g. cereals), which can be separated by an intercropping crop. Crop rotation requires that each parcel be covered by three different crops over three years, including in particular atmospheric nitrogen-fixing plants. Crop rotation makes it possible to take advantage of natural mechanisms to limit crop work and synthetic input loads. Among the benefits of crop rotation are the fertilization of the soil and the increase of the nutrient content in the soil and therefore the increase in productivity. Crop rotation also minimizes pests and diseases, which leads to a significant reduction in the use of inputs.
Association of Cultures
Crop blending is a technique that involves growing two or more crops on the same plot and using the same resources. (nutrients –water – air . . . ). The combination of different crops on the same plot makes it possible to enhance natural resources and regulate biotic factors. One of the particular functions of crop association is to interlace crops that are “attractive” for biological pest control and thus preserve the main crop. Similarly, competition and complementarity between associated crops support nutrient cycles in the soil and maintain soil structure and fertility as well as resistance to pests, diseases and weeds.
There are three categories of crop association:
– Mixed association: this technique is based on the association of trees with vegetable crops (e. g. the association of palm trees and vegetable crops within oases)
– Permanganate association: this type of association is characterized by a simultaneous production cycle of two crops (e. g. tomato and pepper)
– Temporary association: this type is based on the association of two or more crops that do not have the same production cycle (e. g. lettuce – tomato)
This technique makes it possible to:
– Strengthening cultural diversity and securing incomes
– Optimize the use of space
– Protect soil and crops by limiting the use of synthetic inputs
– Improve production quality and quantity
Agroecology is an integrated approach that combines several social, environmental and economic benefits but, like any system, has limitations and disadvantages in all environmental, social and economic aspects (Table 2)
In order to successfully set up an agro-ecological system and achieve its objectives, it is necessary to combine knowledge – making local producers and innovative scientific knowledge in the various fields of research (agriculture, ecology, sociology, economics). In this context, the transition to agro-ecological techniques can be seen as agronomic, social and academic innovation.
Today, the adoption of agro-ecological techniques continues to develop on different levels and at different scales all over the world, with the support of several organizations (FAO, NGOs, associations, etc. ) with the collaboration of public institutions.
