Nitrogen Fixation

We talk about Nitrogen Fixation a lot in Permaculture. But what is it exactly? In this article, we will learn what nitrogen fixing is, how it happens, why it’s important, and how you can accelerate it in your garden for the best, strongest, most healthy and nutritious plants
possible.

It all starts with soil. Healthy soil makes healthy plants, which, in turn, makes healthy humans.

So, without further ado, let’s jump right in!

 What is Nitrogen Fixation? 

Plant growth and development depends on nitrogen.   And even though nitrogen accounts for about 78% of the atmosphere, most plants cannot access it.

Certain plants, however, the nitrogen-fixers, are able to work, in conjunction with bacteria in the soil, to make it accessible to themselves and others. They convert atmospheric nitrogen, into the combined or fixed forms of nitrogen, such as ammonia and nitrate that other plants need. But it’s nothing like pouring big bags of commercially created chemicals on the ground. It’s actually the proper way – the way Nature has devised over 4.6 billion years.

Why is Nitrogen Fixation Important?

There are so many reasons.

Having nitrogen in the soil enables the retention of more nutrients, with a higher availability of those nutrients, which makes for a more diverse population of soil organisms and, in turn, healthier and more fertile plants. It’s about generation and regeneration.

Biological nitrogen fixation, is also the solution to all the horrible damage caused by industrial-scale mono-cropping systems.

The wide-spread, normalized use of chemical fertilisers and the pesticides that go with them, has created a world of problems for the environment, and for all of us living in it, human or otherwise.

It:

• Contaminates both soil and water
• Kills necessary soil organisms
• Degrades fish and wildlife habitat
• Kills birds, fish, bees & other pollinators
• Causes toxic algae blooms
• Reduces oxygen content in waterways
• Is also the likely cause of diseases in humans
  • Hemoglobin disorders
  • Alzheimer’s
  • Diabetes
  • And undoubtedly more…

In addition to being extremely toxic, the large-scale mono-cropping industry is also far too labor intensive to be sustainable. It’s dependance on the trucking industry only magnifies the problems.

How do Plants Actually Fix Nitrogen?

They don’t. Bacteria do. Rather, it’s the result of symbiotic plant/bacteria relationships. All the nitrogen necessary to life is in the air, but plants cannot get it. It takes this symbiotic relationship to make it available. Each party needs what the other naturally produces, so it’s mutually beneficial. It’s similar to the oxygen/carbon dioxide exchange that happens between plants and animals.

Nature is as good at creating these kinds of relationships
as the dominator culture is at destroying them.

Through photosynthesis, plants produce carbohydrates, which the micro-organisms need. And in return, the microscopic soil organisms fix the nitrogen around the roots of the plant so it can grow big and strong.

This becomes available to nearby, non-N-fixing plants, when the N-fixing plant dies and it’s nitrogen-rich leaves decompose into the soil. It is simple, elegant and very effective.

Rhizobium & Frankia are the two main types of microbes that participate in this.

Rhizobium

The most powerful symbiotic plant/bacteria relationships are between plants in the Fabaceae family…legumes…and Rhizobium and Bradyrhizobium bacteria. All manner of legumes, beans and peas participate in these relationships. Clovers, vetches, alfalfa and lupines are in this family, as well, each having an overwhelming number of varieties and sub-species.

Here’s how it works. The bacteria colonize (in a good way) the root system, causing the formation of little nodules amongst the root branches and hairs. These nodules house the bacteria, and is where the transfer takes place, each feeding the other.

The nitrogen fuels the growth of the plant, causing bigger leaves, which, in turn, increases the amount of photosynthesis that becomes possible…which…is more food for the microbes, and then more nitrogen for the plant…a virtuous circle!

The resulting nitrogen-rich seeds have a higher germination rate. And after death, the plant’s nitrogen-rich leaves fertilize the soil even more as they decay. It just keeps getting better!

Frankia Bacteria

There is a group of Actinobacteria called Frankia that partners with different types of N-fixing plants. Theses plants are called Actinorhizal nitrogen fixers.

[Notice the similarity in their names? They both start with “actino,” which means “having
raylike structures.” Bacteria means bacteria, obviously. And “rhizal” means a part “resembling or connected with a root.” So, it seems their raylike structures reach out and intermingle with each other. Isn’t that sweet?! ]

Actinorhizal nitrogen fixers can be found in many different types of eco-systems and are frequently pioneer species, in depleted environments. They remediate disturbed ground, improving it and allowing the start up of the plant succession process. They can be found amongst the following families.

• the Birch Family – Betulaceae
• the Austrian “pines” – Casuarinaceae
• the Oleasters – Elaeagnaceae
• the Bayberry Family – Myricaceae
• the Buckthorn Family – Rhamnaceae
• the Rose Family – Rosaceae

People and their local experts frequently complain about “invasive”
weeds that are really just pioneer plants trying to fix the depletion
caused by civilization.

• The bare, exposed earth of vacant lots.
• Lawns.
• Plowed up fields.
• Forest fires.

   

On Pioneer Plants

Campaigns are launched to eradicate them – poison, burn, chop down, pull up by the roots – and everybody involved fancies themselves a hero. 
 
There are genuinely invasive plant imbalances, like blackberries in the Pacific Northwest or Himalayan ginger in Hawaii. But these kinds of invasive situations are inevitably the result of human activity.  We seem to think checks and balances are only for our governments.

Pioneer plants are not in this category.

But, Healthy Soil Needs More Than Just Nitrogen, Doesn’t It?

Yes, of course. But nitrogen is a key element in plant growth. It’s found in every single cell of the plant, in it’s proteins, hormones and chlorophyll.

Other components of healthy soil that plants need for optimum growth and
resilience include:

• Phosphorus – aids in photosynthesis.
• Potassium – increases disease resistance.
• Calcium – essential for root growth and health.
• Magnesium is to chlorophyll as iron is to blood.
  • (In fact, chlorophyll is nearly identical to red blood. The one
    difference is, that, where we have atoms of iron, they have atoms
    of magnesium. Isn’t that fascinating?!)
• Sulfur – part of the amino acids in plant proteins and necessary to
  energy production.

There are also necessary trace elements such as iron, manganese, copper, zinc, boron and molybdenum that each make important contributions. 

But nitrogen is the foundation, so this is where we start.

Are There Other Ways to Increase Nitrogen in the Soil?

Yes.  Nitrogen fixing plants, are great because they naturally do the work for you. (Although it’s not really for you, is it? They do it for themselves.) One of the main points of permaculture is to work with natural processes, rather than against them. So focusing on planting green manure crops like sanfoin or borage to turn under, or just cut down in the fall, makes a lot of sense.

But you can also add composted chicken, goat or horse manure, kitchen scraps like banana peels, eggshells and coffee grounds, menstrual fluid, your placenta, water and dead fish from your fish tank, worm castings, a pet cemetary… 

It’s the original Life, Death & Regeneration cycle. The Real One.

In Conclusion

Nitrogen is the foundation for healthy soil, plants and plant-eaters. It’s naturally occurring, so if you understand the process of nitrogen fixation, you can incorporate it all throughout your property. It’s abundant goodness will grow from year to year. They say you can never plant enough N-fixers.

I hope you enjoyed this article. I tried to write it in a way that is easier to understand than all the overly dry scientific sounding stuff out there, while still digging down to the same depths. I hope I succeeded.

Please feel free to leave a comment. I love to hear from you.