Soil Health Friday – Nitrogen Cycle?

Soil chemistry can be overwhelming and complicated. This does not dilute the importance of our need to understand as much of it as possible if we want to grasp what is happening in our fields.

If you are following the blog posts, you see my weekly attempt to explain, in detail, the soil structure and functionality so that the reader and grower can use this knowledge to increase their efficiencies with their fertility management on their farm.

Often the word chemistry is thought to be synonymous with “man-made” or “synthetic”, however, chemistry is as natural as H20! As an additional example, inorganic forms of nitrogen are naturally occurring. These forms of nitrogen are transformed through biological processes in the soil profile, creating a more plant assimilable form (nitrate, inorganic). I have always found this to be fascinating because this is where chemistry and biology intersect within the medium, that is soil.

Nitrogen dominates the discussions as it is often considered to be a core driver for plant growth. We must recognize the importance of nitrogen in both the plant assimilable form as well as the organic forms (amino acids/protein/etc. within our organic matter, for example). Also, we should keep in mind the role nitrogen can play in aiding our microbes with a balanced diet, to help further drive carbon breakdown and nutrient cycling.

A very well documented but often overlooked aspect of nitrogen is the nitrogen cycle itself. This has been around a long time and if you Google search it, you will come up with various graphics that help to visualize the cyclical nature of nitrogen.

This is important because as you see in the below picture, we are fixing nitrogen through the natural process that legumes offer to our systems. They are taking atmospheric nitrogen (N2) and converting it to ammonia (NH3), what you see on the roots. This is done through a symbiotic relationship between the plant’s root exudates and n-fixing bacteria (rhizobia) The typical nitrogen cycle diagrams show assimilation occurring in the nitrate form. We do know that plants can also assimilate ammonium, which is made available from OM mineralization, there has also been ample research showing the plant assimilation of nutrients through microbes themselves (Rhizophagy Cycle, PhD. James White), but for this write up we will focus on nitrate. Worth noting, that in most aerobic soils, nitrogen converts to nitrate rather rapidly and is the most frequently absorbed form. Nitrate is also the most leachable form of nitrogen, more on this to follow.

So why does all this matter?

This goes back to a blog I wrote a few weeks ago about nutrient cycling. If we can understand the forms in which nitrogen takes and are assimilated, we can better adjust our fertility management and crop rotations. Here at Vitalize Seed, we strive to reduce or eliminate fertilizer needs for our growers. We are doing this by balancing the residue breakdown through carbon: nitrogen ratios, and also by keeping the N (for sake of this blog) in the cycle! This is why we have a highly diverse Spring blend that captures N and fixes N simultaneously (through balancing complementary plant species) and a fall blend that will further mine N in our systems, with a sound balance of N fixing capabilities as well.

As you can see from the last paragraphs the idea is to keep the N in the system and balance the residue breakdown so that when N does come available, we have adequate “miners” to “grab it”, allowing us to make our soils far more self-reliant and the entire system is more efficient. As we increase this efficiency we see higher microbial functionality in our soils, resulting in healthier crops and better nutrient cycling.

Thank you for considering Vitalize Seed as your seed source.

Albert

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