Nitrogen Fixation

Article #3: Nitrogen Fixation by John Tobe

Here is how nature provides nitrogen for plants in the soil.

Leguminous crops such as alfalfa, clover, etc., are probably, next to lightning, the most important sources of organic nitrogen.

While some of you may believe that the gods and nature have neglected the good earth and mankind, I want to assure you that this is not true.

It is fixed by natural phenomena and occurrence that all of the nitrogen required by the good earth is put into it by a simple, natural, trouble free way. It is only up to man to use it wisely.

It is my humble belief that the Lord did not ever intend mankind to do His work for Him. In truth, man is lucky if he can do his own work properly—never mind doing anything for the Lord.

Leguminous crops are properly established and divided through the entire earth’s surface, including the deserts. This family not only contributes a wide range of forage plants but also plants used extensively for food, and, last but not least, as beautiful ornamentals. It consists of more than 430 genera and 10,000 species.

This family is probably one of the easiest of all to recognize because of the shape of the fruit which is invariably a legume or true pod, opening along tube sutures.

Many noted and respected authorities consider this family the most important family of plants in the horticultural world or any other world, says I!

When I talk to you about technical things, I can just feel I you drawing into that thick shell of yours so that you’ll be impervious to my railing. But, says I, “How are you going to know and learn about nature’s way if you don’t listen?”

It is written that occasionally the road to knowledge gets a bit technical … but bear up to it—there is much virtue and value therein.

The most important characteristic of this family is the fact all of them have roots or tubercles or nodules which certain soil microorganisms invade.

Here the bacteria obtains carbonaceous food from the plant and carries on the nitrogen fixation process, storing up the resulting nitrogeneous food material. This, if not used by the plant itself, is added to the soil when a plant dies and its roots decay … thereby becoming available to other plants.

Invariably leguminous crops leave the soil in much better shape when they die than it was when they first started to grow. That is why clovers, soya beans, vetches and alfalfa are treated as cover crops or green manures because they positively and definitely, without additional cost, increase the nitrogen content of the soil—apart from adding humus.

I’ll just name a few members of this family at random: the mimosa, acacia, genists cytisus, laburnum, wisteria, robina, lupinus, clover, alfalfa, beans, peas, vetch.

The way scientists would describe nitrogen fixation is as follows:

“Gaseous nitrogen diffusing into the soil from the air is converted into useable nitrogen by the mechanism of the leguminous plants, combined with the bacterial action of the microorganisms living in its roots. This act of conversion is what is known as nitrogen fixation and by this means nature provides simple nitrogen to the earth for its crops.”

Therefore, not only is this plant able to secure the nitrogen it needs even when there is insufficient nitrogen in the soil … but these legumes actually add to that supply and as far as nitrogen is concerned, leaves the land more fertile than before they grew.

Animal manures are invariably rich in nitrogen and the reason is very simple and obvious … because animal fare and forage is often heavy in leguminous crops and they contain large quantities of nitrogen.

There is one important factor that should ‘interest horticulturists about this family and that is that the flowers are invariably very showy and some of our most important trees, shrubs and vines belong to this group.

Commit this to memory…this family of plants has the rare ability to absorb free nitrogen from the air.

While back more than 2,000 years ago they did not perhaps know what we know, and this is that these plants provided the much needed nitrogen to the soil, the Romans used them extensively for soil improvement.

John Tobe is deceased, and “The Provoker,” his publication in which this article appeared, is defunct.