Definition - What does Nitrogen Fixation mean?
Nitrogen fixation is the process by which the nitrogen in Earth's atmosphere is converted into ammonia (NH3), making it available to living organisms. This is essential for many forms of life as it is required for the biosynthesis of the basic building blocks for plants, animals and other life forms including grapevines.
WineFrog explains Nitrogen Fixation
In many vineyards, cover crops are used in order to create an environment for nitrogen fixation. Nitrogen is vital for the vine (and other plants) as it helps to form its DNA and RNA. However, not every cover crop has the ability to fix nitrogen into the soil.
The best cover crops for nitrogen fixation are those with bulbous roots, like legumes (fava beans), clover and bell beans. They also create a symbiotic environment for the development and sustainability of nitrogen-fixing bacteria. When the cover crops are tilled into the soil as spring arrives, they decompose and deliver the nitrogen as a usable form for the grape vines.