What is Organic Nitrogen
Organic nitrogen usually refers to a nitrogen compound sourced from a living material. It’s an important part of soil organic matter and plays a key role in the nitrogen cycle that supports healthy crop growth. Organic nitrogen is usually divided into two categories: (1) Nitrogen from organic residues or (2) Nitrogen from organic matter or humus.
But what exactly do farms need to know about organic nitrogen?
- It refers to the carbon nature of its molecular structure. Compare this to inorganic nitrogen such as nitrite, nitrate, and ammonium forms that don’t have carbon in its molecule.
- It’s much less efficient in providing nitrogen nutrition versus inorganic sources. The inefficiency of organic sources is illustrated by applications on turf on sand-based golf courses. The inorganic nitrogen nutrients, which may range from 8 to 16 percent nitrogen in the form of nitrates, must be applied every 30 to 45 days to maintain an acceptable level of dark-green color.
- It can enter septic systems from sources such as bodily wastes, discarded food material, or as components of cleaning agents.
- It’s usually found in non-water soluble forms due to their less stable nature. Whereas, with inorganic nitrogen sources, such as our common synthetic mineral salts, these are usually found dissolved or readily water soluble and stable, therefore making it more easily leached into the ground or soilless farming growing mediums. In fact, a USDA study shows that 50-82% of all inorganic nitrogen fertilizers are lost into the atmosphere or into surface or ground water.
- Often contributing to high water turbidity (otherwise known as water cloudiness), organic nitrogen is highly dependent on mineralization to turn it into a stable form of plant available Nitrogen-Nitrate for plants to be able to use as a food source.
How Plants Use Organic Nitrogen
Organic nitrogen becomes available when there is a decomposition of its compounds, which for soil-based farming, is done through soil organisms or microbes. This is not the case obviously for soilless farms.
Now, plants are only able to take up nitrogen in two forms: nitrate (NO3-) or ammonium (NH4+) – both of which can come from nitrogen fertilizers. Once the organic nitrogen has been placed in the growing medium or soil, chemical changes begin, turning into plant-available nitrogen.
"Now, plants are only able to take up nitrogen in two forms: nitrate (NO3-) or ammonium (NH4+) – both of which can come from nitrogen fertilizers. Once the organic nitrogen has been placed in the growing medium or soil, chemical changes begin, turning into plant-available nitrogen."
For the purpose of this article, we’ll simplify things, and focus on the three main forms of organic nitrogen nutrient transformation:
- Mineralization – Microbes transform organic nitrogen into plant-available nitrogen. Over 90% of nitrogen in soil organic matter form is unavailable to plants so this is a very important step in order to give the plants what it needs.
- Immobilization – As the microbes decompose the organic material, they utilize the available nitrogen which then converts it into organic nitrogen compounds. It should be noted that this step temporarily reduces plant-available nitrogen. However, this nitrogen becomes available once again once more decomposition occurs.
- Nitrification – The largest quantity of organic nitrogen that is taken up by plants is usually in the form of nitrate nitrogen (NO3-). Under warmer conditions, ammonium (NH4+) can rapidly change to nitrate nitrogen (NO3-), making it even easier for plants to absorb through their roots. However, if not managed properly, nitrate nitrogen (NO3-) can leach and denitrificate.
"Microbes transform organic nitrogen into plant-available nitrogen. Over 90% of nitrogen in soil organic matter form is unavailable to plants so this is a very important step in order to give the plants what it needs."
Soilless Systems and Organic Nitrogen
If you have been following our articles for some time, we are sure that you are aware that soilless farms lack the microbes and synergies needed to benefit from the Nitrogen cycle which requires biological processing as described in the steps above.
However, we’d like to bring mention that Chilean Nitrate is largely used as a form of organic nitrogen that is OMRI certified. More popular amongst soil farmers, water-soluble Chilean Nitrate typically is available in a 15-0-2 NPK ratio and is the only non-synthetic mineral source of organic nitrogen.
It is naturally sourced from Northern Chile’s extremely dry climate and desert which has benefitted from close proximity to Chile’s air and sea.
"More popular amongst soil farmers, water-soluble Chilean Nitrate typically is available in a 15-0-2 NPK ratio and is the only non-synthetic mineral source of organic nitrogen."
Known for solid, granular form, it has been successful largely by organic soil farms, for providing nitrogen, potassium, iron and selenium to plants in both cold and warm temperature soil while improving the nutritional quality of crops by increasing protein, albumin, amino acids, vitamin B, and micronutrient content. However, Chilean Nitrate should not be relied upon as the sole source of Nitrogen.
For part 4, we look at the carbon aspect of organic hydroponic nutrients and the key things a farm needs to understand for their guaranteed analysis.