Green manuring is a very ancient agronomic practice that aims to improve the structure and the fertility of the soil by providing organic substance. This contribution does not occur with fertilizations but with the sowing, cultivation and, where possible, the burying of some herbaceous species.
This practice is not only used in the Organic, as in our case, but also by conventional agriculture, wanting to vary vineyard fertilization plan.
There are many herbaceous species suitable for green manuring in vineyards, with peculiar characteristics, here are the most used also in our vineyards:
- Legumes bring nitrogen to the soil (nitrogen-fixing activity). Thanks to their thick taproot root system (which explores the soil in depth) they are able to facilitate the drainage of water in very clayey soils. Among them, we findthe field bean, the vetch, the fodder pea, the bean,the clover.
- Grasses have a rapid growth and little need for water, they are generally used in association with legumes. Thanks to their expanded root system, they improve the surface structure and aeration of the soil. The most used in the vineyards are oats, barley and ryegrass.
- Cruciferous trees, also with taproot roots and relative qualities, quickly produce a good amount of biomass which helps to improve the characteristics of sandy soils and makes lighter and more aerated the soils with a large clayey component. Some species also have a biocidal function against nematodes and fungal parasites, very useful in the cultivation of vegetables. Crucifers are for example rapeseed, mustard and rocket.
The sowing of suitable species for green manuring between the rows of vineyards must take place immediately after the harvest. This allows the seedlings to get born and develop a good root system during the autumn. After the winter they will be ready to vegetate quickly and in spring they can be mowed and buried as the soil allows it.
Thebest time for mowing / burying is when the plants are in pre-flowering: in this period the nutrients and the percentage of fiber are at a point of balance and the plants degrade quite quickly. Mowing the plants in that period prevents them from becoming weeds for the vineyard, with the flowering and the consequent production of seeds.