Agroecological  management of soil fertility
in the Minervois
(Languedoc-Roussillon, France)

Gestion de la fertilité des sols par les engrais verts, ici par de la phacélie.

In the Minervois, the steps aimed at developing autonomous peasants in an agroecological context led BEDE and its local collaborators from Chemin Cueillant to become interested in sustainable soil fertility management, a central pillar of agroecology. Although BEDE generally works more to promote exchanges between local peasants to share their knowledge adapted to the territory, this step has made it necessary to search further for alternative techniques. Agroecological innovative methods exist that go far beyond organic or ancient practices, sometimes little used and not able to efficiently respond to the challenges of soils depleted as never before, plants weakened by inadequate selection, and a growing parasite pressure.

State of the soil : a desastrous situation

…result of passed practices

In the Minervois, as in a large part of the Languedoc subject to the intensification of viticulture, fertility was often approached through a short-term productivist lens. Chemical fertilizers (Nitrogen, Phosphorous, and Potassium) were usually applied annually to crops, allowing to maintain a high level of production despite a progressive degradation in organic matter (humus) in the soil through natural mineralization, particularly fast in the Mediterranean climate.
The Minervois, where agriculture has been almost exclusively viticulture for a long time, is one of the areas with the lowest levels of soil organic matter in the region.
Moreover, the massive use of synthetic pesticides as well as copper, a powerful fungicide, have contributed to the rarefaction of numerous life-forms in the soil (insects, worms, microorganisms…). The almost complete disappearance of earthworms in several land plots taken over by farmers of Chemin Cueillant, such as in Mailhac or Azillanet, is a strong witness to this.

…with numerous consequences

> Drastic reduction in natural soil fertility: without humus, the mineralization of organic matter and the freeing of natural nutritional elements is weak. Plants therefore have difficulty feeding themselves correctly without a regular addition of an easily assimilated form of nutrients, while at the same time these are exactly what is rendering the health of the plants more fragile, and even reducing the quality of the food product.
> Through lack of biological activity, certain chemical elements are even largely unavailable for crops though present in the soil.

 and beyond the simple problem of fertility :

> weakening the immune system of the cultivated plant leaves an easy access for diseases
> The terrain is favorable to pests and diseases due to lack of antagonist biological activity in the soil and on the plant (fungi that fight diseases, auxiliary insects for pests)
> poor infiltration of rainwater and excess run-off from intense rainfall when the soil is poorly structured means a poorer winter recharge of soils and leaving crops in a fragile state to cope with drought

Revitalization of the soil by green manure

All of the above shows why an ecological transition of agriculture or organic agriculture of the farms in an area cannot afford not to have a profound reflection on this question.
The farms of Chemin Cueillant do not escape this dilemma, even if their activity is often based on valuing low-yield but high quality viticulture, and therefore little greedy in fertilisation. Even in this case, a readjustment is required with regards to applications locally adapted to the diversity of the soil and climate conditions, the structure of the farms, and the means that each can access to respond to the question.

Training

Februray 2012 : The training with Michel Barbaud, an agronomist who developed a method to revitalize the soil, organized by the farmers of Chemin Cueillant with the help of the Civam bio 34, brought together around 20 producers.

Method presented : addition of composted organic matter rich in lignins to form a stable humus.
Materials : shredded green waste from the municipality or residue from forestry + microbial preparations based on lacto-fermentation with yeasts to inoculate with fungus that facilitates the process of aggradation of soil humus with the compost, while at the same time providing enough nutrients to plants in the short term.

Cultivation of green manure on the farms of Chemin Cueillant

Difficulties getting organic matter brought directly to the soil and the costs of such a step :
 Cultivation of green manure for three test farms of Chemin Cueillant in Gimios, Mailhac, and Azillanet. Certain plots were sown in the autumn/winter of 2010 with several beneficial crops :
rye in an olive orchard in Gimios,
faba bean between certain grapevines in Azillanet,
combination of vetch and oat in Mailhac.

Difficulty getting organic seed at a reasonable price :
Taking advantage of the natural cycles of weed plants (abundant in a mild climate): wild arugula, and wild oat.
The choice of waiting until the last moment to destroy weeds allows for these to bring a maximum of organic matter to the soil.

In 2011 and 2012, more significant seeding was carried out in the autumn :
mixes of oat and vetch, sometimes with barley and faba as well;
more complex mixes that include phacelia and mustard to better decompact the soil.

 >  Research and contact with local peasant farmers capable of producing them,

> Research on well-adapted population varieties to be reseeded without degeneration.

Autumn 2013, was rather unfavorable to sowing green manure, and few were sown despite the fact that a grouped order of seed was proposed, including a very interesting variety of faba for the first time, supplied by a farmer in the Tarn and Garonne department, and that we wish to have multiplied by a local cereal farmer. Faba appears to be a master plant allowing for good management in restoring soil fertility.

Zoom on green manure

End of 2013, we were able to propose a summary of this work to the farmers of Chemin Cueillant in the form of an evening of exchanges on the topic, and the distribution of a small summary report.

Training for the maintain of grass cover in vineyards

BEDE also participated in a training day organized by the federation of CIVAMs of the Languedoc-Roussillon on the theme of permanent grass cover in vineyards, where the CIVAM LR invited Xavier Delpuech of the IFVV (French Institute of Grapevine and Wine) to present. Several farmers from Chemin Cueillant participated, and the day provided for visiting planted vineyards in the Corbieres as well as vineyards of Chemin Cueillant, planted in the autumn with green manure.

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