The Nitro-Mag Liquid Urea Fertilizer Complex

The advent of AI has given us a new tool to use in research that in the past would have required lengthy work and review.   The massive amount of research on all subjects is now available with a few keystrokes as well as mathematics and scientific equations.   I have used these tools to help us understand what chemically is taking place when we react Urea and Magnesium Chloride (MgCl) together. 

As I have stated earlier, I did not have knowledge of this Nitro Mag Complex when first melting the Urea in with the MgCl.  I was looking for a source of Magnesium that was usable in agriculture.  From my work with melting Urea with Sulfuric Acid in the mid 1980’s I was aware of the benefits of liquid Urea to plant health.   The idea of mixing Urea with the MgCl came because of experience and looking to find a way of getting more Magnesium to the plants.   I was also wanting to introduce melted Urea as a more efficient Nitrogen source. 

Nitro Mag became the result of those what if wonderings.   The first large batch was dismal as blends were attempted without heat.  Many lessons were learned along the way.  Finally at a GT facility in Hastings NE the first batch was brewed, and an existing sample looks as good today as it did when made.  

If you're not familiar with the basics of Nitro-Mag and stabilized amine Nitrogen - start HERE.

Nitro-Mag Definitions:

Chemical Compound

A pure substance formed when atoms of different elements are chemically bonded in fixed ratios.

A compound is a single, well-defined molecule or lattice

Urea is a compound CO(NH2)2.  The same is true of Magnesium Chloride MgCl2. 

Chemical Complex

A complex is a central Atom/Ion (usually a metal) surrounded by ligands that donate electron pairs.   Reacting Urea or Urea Liquor with MgCl creates a chemical complex.

Magnesium (a Metal) forms the Octahedral coordination and bonds to the Carbonyl Oxygen of Urea.

Urea acts as a monodentate ligand with its carbonyl oxygen.

Chloride with its negative charge helps balance the complexes overall charge making it a neutrally charged complex.

Solution

A solution is a homogeneous mixture at the molecular level.  Urea dissolved in water or melted urea is a solution.   32% Nitrogen mixed with Ammonium Thiosulfate is also a solution.  

The Complex Advantage

1.        The Mg2 locks up the Urea into a stable complex.

·      This prevents salting out.

·      Prevents biuret formulation.

·      Reduces Ammonium volatilization.

2.        Chloride provides the ideal anion. 

·      Contributes high solubility.

·      Does not compete with Urea for the Mg2.

·      Enhances freezing point depression.

3.        Nitro Mag has a high N: Mg Molecular Ratio

·      Favors the formation of U6Mg Complexes

·      Provides cold stability while keeping the N level high.

The Nitro Mag Complex creates a stable product that resists salting to subzero degrees.  This provides the advantage of secure winter storage over other commercial Nitrogen fertility products.  

The Nitro Mag Complex is a Urea-Magnesium chloride coordination system in which Mg2+ acts as a Lewis acid, accepting electron pairs from the carbonyl oxygen of urea.  At a bulk molar ratio of approximately 12-18: 1 (urea: Mg2+), the liquid contains Mg2+ centers coordinated by multiple urea molecules and H20, with the Chloride ions serving as counterions.  

The Role of Heat in Nitro-Mag

Heating the MgCl2 does not just melt the Urea it also drives the Complex formation.  When mixing dry urea to MgCl without heat the process becomes endothermic or kinetically slow to form the intricate Complexes. 

By heating the MgCl the formation becomes faster, the Mg2 shells loosen, the urea molecules become more mobile and the coordination complex forms more completely and more uniformly.

When heated the urea dissolves more readily, the carbonyl oxygen of urea becomes more available, and the system reaches equilibrium faster.   This makes for a clearer, more stable cold tolerant product that improves shelf life.  

With the use of heat we are not just melting urea, we are activating the chemistry that makes Nitro Mag work. 

Heating directly contributes to the formation and completeness of the urea-MgCl2 coordination complex.

The question comes up then do you get the same results if you use a heated Urea Liquor instead of heating the MgCl?  The answer is yes.  What matters is that at least one side brings enough thermal energy to dissolve any dry urea fully, loosen the Mg2 hydration shells, allow urea’s carbonyl oxygen to coordinate, and reorganize the hydrogen-bond network.  

The hot Urea Liquor has higher molecular mobility, lower viscosity, more exposed carbonyl oxygen, and fewer hydrogen-bond constraints.  This contributes to the Urea being very ready to coordinate with the MgCl2 when reacted together.

When using cold MgCl2 it holds its hydration shells tightly around the Mg2 and has slower ion mobility.  Adding dry Urea to cold MgCl will create an endothermic situation where the complex will try to form but due to the temperature it never fully will.  

When cold MgCl reacts to the hot Urea Liquor the temps rise towards the middle and the Mg2 shells loosen and the complexation takes place.  

Either Manufacturing process achieves the same goal which gives us exactly what we want in a commercial formulation.

Stability

Product Stability

There are two kinds of stabilization that we deal with.  One is the product stabilization that the complex gives us as previously discussed.  Storage, handling, nutrient availability among others is provided by the Nitro Mag Complex. 

Soil Stability

The next form of stability is when the Nitro Mag product is taken out of the tank and put on or in the soil.  What happens then.   Stabilized Amine Nitrogen or keeping the Nitro Mag in the Amine or NH2 form is important to how our product is perceived and sold at the farm gate.

NH2 Nitrogen is the Urea-derived amide or amine Nitrogen source.  Urea in the dry form and in the liquid melted urea product contains the NH2 form exclusively.  Nitro Mag is also in the NH2 or Amine form. 

The NH2 form will stay that way indefinitely in storage for long periods of time.   The other half of the Stability story starts when any of these products are applied to the soil.  A stabilized amine nitrogen (SAN) is NH2 that fights off being converted in the soil to an NH4+ or ammonium form of Nitrogen.  That conversion is caused by the biological Urease Enzyme that the soil is loaded with. 

The Urease Enzyme is one of the efficient enzymes in nature.  There are millions of urease producing microbes in a gram of soil, and their job is to turn NH2 into an ammonium carbamate and then into ammonium NH4. 

With dry Urea and liquid melted urea, the conversion starts immediately with contact of the soil.  Varying soil conditions such as soil temperatures and soil pH can either speed the conversion up or slow it down.   Soil at 70 to 90 degrees as well as being moist will accelerate the conversion.  Urease tends to concentrate at the soil surface which will convert any Urea product faster if sprayed on the surface. 

Colder soils and deep banding where there are less Urease and into more acidic soils will help slow the conversion down. 

We can slow down the process, but it will eventually happen.  The same is true for the conversion of NH4 into Nitrate or NO3.  The longer you can put off the conversion the more chance you have of the roots picking up the NH2 before it is converted.

The Nitro Mag Complex with its neutral charge and the free Chloride will increase the ionic strength, reduce microbial activity locally and will slightly depress the urease activity.   Placing NM 3 to 6 inches deep will slow the hydrolysis up to 3 days. 

By adding Fulvic Acid to the NM it will alter the microenvironment around the NM droplet.  The Fulvic Acid will help with pH buffering and create a slight acidic micro-zone around the Urea. 

Fulvic acid chelates metal.  Urease is a nickel-dependent enzyme.  Fulvic will Chelate Nickle, Copper, Zinc, and Iron.  It will also have a chelating effect on Magnesium.  By Chelating the free Nickel in the soil, it can slightly suppress the urease synthesis for a short time.  It will slow the process up by the most 24 hours if conditions are right for the Urease synthesis.  

By adding Ammonium Thiosulfate or what we call Thio to our mix.  Thiosulfate creates an acidic low oxygen micro zone that will help deter the conversion of NH2 to NH4.  When mixing UAN (32%) and Thio, that zone exists for a short duration. 

Nitro Mag and Fulvic plus ATS stacks multiple mechanisms such as Mg2 coordination, high ionic strength, reduced water activity, fulvic driven Nickel chelation, and ATS acidification.  Together, they stretch the time before the urease hydrolysis curve takes over.  Especially when banded.  

By deep banding I’m estimating 3 to 5 days before the urease hydrolysis takes over and starts converting the NH2 to NH4 and that into NO3.    

A straight melted Urea applied to the soil will start to convert to NH4 immediately.

The advantage of staying in NH2 form to be taken up by the roots is that NH2 is the precursor to amino acid production in the plant.  NH2 is more efficient and does not need interior plant conversion that takes time and energy to get the NO3 and NH4 converted into the NH2.  NH2 then forms the Amine Group that will begin the production of the 21 amino acids that will form long chains which are converted into Proteins.

Science Has a Solution

What Nitro Mag is doing to keep NH2 from converting is along the organic lines with the use of the complex and fulvic and or ATS.  Throw in deep placement or banding and that will hold off the hordes of the Urease enzymes from attacking for a matter of days. 

There is a product available on the market that can extend that time up to 14 to 21 days.  This product called Limus blocks Urease enzymes from intercepting and converting the NH2 into NH4.   The longer we can stall the conversion the more chance the plant has of taking up NH2 and being more efficient.  A 14-day grace period on top of what we are doing organically in season will be a huge advantage to keeping our amine nitrogen in NH2 form and a good chance the plant will pick it up as such. 

The downside is it increases the cost of the product per acre.  That added cost is buying plat efficiency so maybe it would be acceptable at the farm gate. 

My feeling is we can add less of the Limus product due to our built-in suppression with the fulvic and ATS. 

These products target the Urease enzyme and will delay hydrolysis up to 14 days or longer.  They will not eliminate beneficial microbes at field rates; their action is Urease specific.

These specific products, although adding cost, are well proven to do their job as advertised.  Our sublicensees would be encouraged to sell a Nitro Mag Pro line which would feature these Urease suppressing products for additional revenue.

For the longest duration beyond the organic suppression would require the addition of Limus or Agrotain Ultra to Nitro Mag to have longest Stabilized Amine product on the market. 

Nitro Mag has proven to be an excellent form of plant fertility.  Due to its neutral charge, it accepts additional products such as Organics well.  Crops that are exposed to and metabolize N in the NH2 form will metabolize the NH2 in the plant’s roots.  This will build a larger root system and be more influenced by the hormone Cytokinin, thus improving the plants root to shoot ratios.  Stabilized Amine Nitrogen will support growth by promoting strong lateral rooting.  SAN is directly involved in the reproductive growth of the plants.

Nitro Mag does a good job keeping the Urease enzymes held back due to the nature of the product and its additives.  If we want to extend that period of time, we can utilize products that will help add additional days before the change from NH2 to NH4 takes place.  

Read more about Nitro-Mag in "The Basics of Nitro-Mag" HERE

Marcus Dennis