It’s called “autumn” the magic of peace that descends on the hills after the harvest. Among the rows of vines of the Marchisio Family, this is the moment of the green manure: in the inter-row are planted certain plant species with a seasonal character, which serve to give back to the soil the organic substances, fundamental for a harmonious growth of the vines. The technique of green manure, fundamental in conservative agriculture (and considered for twenty years a “good agricultural practice” even at ministerial level), consists in fertilizing a soil by burying specific herbaceous crops. In fact, green manure is a green, organic fertilization technique used to increase soil fertility. Its importance is equal to that of soil preparation. The technique is easy to apply and ensures excellent results: in fact, it improves the chemical, physical and microbiological characteristics of soils. «The practice of green manure – explains Sergio Marchisio, pioneer of biodynamic viticulture in Roero – is able to produce enormous quantities of nitrogen, and in a perfectly sustainable way from an ecological point of view».
Also for this reason, continues Sergio, the choice of particular green manure crops is decisive, both in relation to the production of biomass (which remains the primary objective) and to the specific needs of the vineyard, such as the contribution of precious elements that enrich the soil in an absolutely natural way. «For green manure, we choose crops that are able to quickly colonize the soil and produce maximum biomass during the winter “rest” period of the vines. In our case, we adopt a mixed solution such as that of “multi-essences”, which seems to us optimal». The most important species are clover, a great source of nitrogen, and then mustard and facelia. «Mustard quickly covers the soil and intensely roots the arable layer», says Sergio: «In addition, it favors the presence of nematodes, tiny worms in the soil that fight bacteria harmful to our vines». Equally precious is the facelia, also appreciated by beekeepers: it’s a plant characterized by a high initial development, which grows well even in soils with little humidity, such as the hills with vines.
The facelia, alone, effectively suppresses any weeds. «And then it’s a “taprooting” plant: it develops roots that then rot and retreat, opening “holes” that ventilate the ground». The robust root system of the facelia, in fact, penetrates deep into the soil, improving its structure. «In addition, its roots capture nutrients, in particular nitrogen, making them available to the vine». The new green mass produced by the green manure, in short, contributes in a fundamental way to the formation of humus, thus improving the fertility of the soil. After all, “pampering” the soil is the mission (biological and biodynamic) to which the Marchisio Family has voted, following Rudolf Steiner’s lesson: «We must start from the slow and constant care of our soil, year after year, to obtain an exceptional raw material: it will be precisely that which will create the conditions for unforgettable wines». Sliding towards winter, the hills seem to be sleeping. And instead – together with clover, mustard, facelia – they are “working for us”: they’re fillin’ up with energy, already thinking about next spring.