Pathway to resilience n ° 7: Generalize agroecology

In France, agriculture occupies more than half of the mainland. Agricultural practices are therefore the greatest force in the evolution of landscapes, and the biodiversity they shelter. The unprecedented intensification of agriculture is manifested today by a deeply degraded environment, a high dependence on many inputs and a great homogeneity of agrarian systems. Dominant agricultural practices are proving to be a source of vulnerability and exacerbation of the threats described in this report. The massive adoption of agroecological practices is imperative to strengthen the resilience of farms and halt the destruction of wildlife.

State of Affairs

Degraded agrosystems with very little resilience

The evolution of agricultural practices since the middle of the 20th century can be summed up in three major transformations. The most visible of these is the destruction of the natural elements of the landscape. The second is the intensification of agricultural practices. The third is the homogenization of crops and the expansion of plots.

Destruction of the natural elements of the landscape

The natural or semi-natural elements of the landscape have greatly diminished. The line of hedges thus fell from 2,000,000 kilometers at the start of the 20th century to 600,000 kilometers in the 2000s. The trend has not been reversed: hedges and groves have lost an average of 24,000 hectares on average. per year between 2006 and 2014. Wetlands are also among the most threatened natural environments with less than 10% in favorable conservation status.

Above: A preserved bocage structure in Boulogne-sur-Mer (Pas-de-Calais). Hedges and edges provide habitat for many animal and plant species. Credits: Matthieu Debailleul, CC BY-SA, Wikimedia Commons. Below: cereal fields characteristic of Beauce (Eure-et-Loir). The landscape is very homogeneous and does not present any habitat diversity. Credits: all rights reserved.

Very intensive use of inputs and resources

The intensive agricultural practices developed during the green revolution largely dominate:
- The use of mineral fertilizers is always excessive (see path of resilience n ° 11) . About a quarter of the nitrogen thus brought to the fields is lost and contributes to the pollution of aquatic environments and the emission of nitrous oxide, a powerful greenhouse gas.
- Irrigated areas have tripled since the 1970s , and represent around 6% of the agricultural area (see path to resilience n ° 5). The increase in droughts could encourage this growth to continue.
- Finally, the consumption of pesticides has never been so high , despite the "Écophyto" plans and other policies implemented. Thus, the "number of unit doses" (NODU), generally used by the authorities to monitor the evolution of pesticide use, continues to grow (Figure 23). Sales of phytosanitary products for agricultural use jumped again by 22% between 2017 and 2018.

Figure 23 : Phytosanitary treatment index in Number of Unit Doses (NODU), three-year sliding average. The objective of the "Écophyto" plan launched in 2008 was to halve by 2018.Source: Commissariat Général au Développement Durable (2018).

A homogeneity of agrosystems at all scales

Like all industrialized production, agriculture resulting from the green revolution is standardized. This results in a loss of diversity at all scales:

- At the plot level, genetic diversity has decreased with the shift from “population” varieties to modern genetically homogeneous varieties (see resilience pathway n ° 4).
- At the farm level, rotations and rotations have become easier (Figure 24). About 20% of arable land is affected by two-year rotations or monocultures. The integration of legumes in the rotations - a practice allowing to renew the nitrogen level - is marginal: less than 2% of the area under arable crops in 2018.
- At the scale of an agricultural region, the expansion and specialization of farms have led to a great standardization (see ways of resilience n ° 1 and n ° 6). Polyculture-livestock systems have regressed in favor of specialized farms.

Figure 24 : Evolution of the diversity index of rotations in France between 1970 and 2000. The homogenization of cover is associated with the simplification of rotations and the enlargement of plots. A score of 10 corresponds to a high crop diversity, while a score of 1 corresponds to a great homogeneity of crops. Source : Schaller (2012).

Alternatives that are progressing, but remain in the minority

Many practices that break more or less markedly with the emerging conventional system: conservation agriculture, organic agriculture, agroforestry, agroecology, permaculture, etc. Most are in the direction of more resilient agriculture, but give unequal levels of priority to the different threat.

For example, organic farming is gaining ground in all territories , at 16% per year nationwide since 2015. In 2019, certified farms accounted for 7.5% of French agricultural land and 14% of agricultural employment. Although growing rapidly, organic farming remains in the minority. It is also proportionately less developed than among most of our European neighbors (France was in 18th position in Europe in 2016).

Links to resilience ?

Natural elements of the landscape

The destruction of natural elements reduces ecological niches and the resources available to wildlife. The result is a seriously degraded biodiversity in agricultural environments , unfavorable to certain essential functions such as pollination or the regulation of pests and diseases. Agricultural soils subjected to agro-industrial practices gradually lose their fertility and biodiversity ( see soil degradation and artificialization ). The destruction of hedges and open-field trees worsens this problem: reduction of organic matter input to the soil, infiltration and retention of rainwater, lower protection against erosion and climatic hazards.

Heavy use of inputs

Mineral fertilizers have become essential for renewing soil fertility, but their production is hampered by the exhaustion of fossil fuels (see path to resilience n ° 11).

Agriculture no longer has any energy autonomy (see path to resilience n ° 3). Total dependence on motorization for agricultural work is a source of vulnerability in a context of declining world oil production.

The severe droughts resulting from the current climate change could have catastrophic consequences on harvests if agricultural systems do not reduce their water needs (see path to resilience n ° 5).

Dependence on pesticides becomes problematic if there is a disruption in supply or the emergence of resistant varieties. The massive use of pesticides contributes to the death of countless insects, plants and other living things that do not harm crops. It is estimated that less than 0.1% of toxic molecules used globally actually reach their targets .

Homogeneity of agrosystems

The genetic homogeneity of crops makes them particularly sensitive to environmental stresses and pests (see pathway to resilience n ° 4).

The lack of crop diversity increases the risk of pest development. For example, common wheat was in 17% of cases preceded by wheat over the period 2006-2009, which promotes weeds and diseases associated with this crop and increases dependence on pesticides. Complex rotations, in addition to promoting better resistance to pests, help reduce dependence on nitrogen fertilizers as they include legumes.

Objectives

We will highlight in this report agroecology, whose principles and objectives respond in a relevant way to many issues raised by the threats described above (Figure 25). Agroecology can be understood as the application of knowledge from ecology - the science that studies ecosystems - to agronomy, in order to design sustainable agrarian systems. A massive agricultural transition is imperative for agroecology to become the new standard and thus strengthen the resilience of farms.

Figure 25 : The general principles of agroecology, and some associated practices Source: Solagro. One of the key points of this strategy is the profound reconfiguration of agricultural landscapes in order to better reconcile food production and restoration of biodiversity. Trees must take back the place they occupied a century ago in our agricultural landscapes. Existing woods and forest areas must be protected: they provide refuge areas for biodiversity, mitigate the consequences of climate change, and make an essential contribution to carbon storage. All of the IPCC scenarios leading to a relatively small rise in global temperature (below 2 ° C) include reforestation and afforestation strategies. Trees are also a source of local and renewable energy that it is essential to develop in the face of the decline of fossil fuels. We must also adapt our ecosystems to the accelerated pressure of climate change. In logged forests, special attention must therefore be paid to the choice and diversity of species.