Nitrogen fixing plants
Employing natures integrated fertility
In permaculture and natural 'farming' there is a strong focus on closing energy and nutrient cycles. The objective is to avoid the need to import external sources of nutrient and fertility by retaining and building it directly on site.
The two obvious was to achieve this is with the use of animals (manure) and plants capable of fixing nitrogen from the atmosphere. While animals have their place, they are not without their challenges and so plants make an ideal starting point. Nitrogen fixing plants develop a symbiotic relationship with soil bacteria and fungi in the root zone to achieve this miracle.
Having access to a ready source of nitrogen (essential for growing green leaves and thus photosynthesis) allows these plants to grow extra fast and quickly modify the local conditions to be more favorable for other plant species. By incorporating appropriate species of these plants amongst other plantings it is possible to accelerate the growth and development of the ecosystem.
The most obvious indicator of nitrogen fixing capability is that of legumes (fabaceae family), plants with seed pods like beans, peas, kowhai, tagasaste and many more. Another group is the actinorhizal plants that do not have seed pods.