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Benefits of Exactrix® Superior Application Uniformity vs. Conventional
 Ammonia and Granular Fertilizer Application Systems

                       Bert Bock
Senior Advisor to Exactrix Staff and a former TVA scientist involved in development of commercial fertilizers .

One of the hallmarks of Exactrix systems is application uniformity for anhydrous ammonia and liquid fertilizers.  That includes application uniformity among openers and along each opener path.  For anhydrous ammonia, this two-way uniformity is achieved by maintaining the ammonia as a high-pressure liquid rather than a mixture liquid and gas both in the manifold and in the distribution lines between the manifold and openers.  Medium pressure is used to achieve uniform application of liquid fertilizers.  With Exactrix systems, anhydrous ammonia application rates for individual openers vary on average 1 to 3 percent from the average application rate for all openers (Figure 1).  This is referred to as the coefficient of variation (CV).  This is far superior to traditional anhydrous ammonia application systems which often have CVs from opener-to-opener in the 20% range or higher and provide a pulsating (sinusoidal) application rate along opener paths as illustrated in Figure 2.  Exactrix systems are also superior to granular fertilizer systems (spinner and pneumatic) that often have CVs in the 20% range or higher, especially with higher application rates and wider application widths (1, 2, 3, 4).  Uniformity of granule application is affected by many factors, including particle size, field slope, and field roughness over which the operator has little control.  These factors don’t affect uniformity of application with Exactrix systems.  

Non-uniform application not only causes some plants to be over-fertilized and some plants to be under-fertilized.  The over-fertilized hot spots are more susceptible to gaseous ammonia moving to the soil surface and being lost to the atmosphere.  Over-fertilized hot spots can also prevent timely access of plant roots to nutrients in the bands and can increase the probability of seedling damage.  

What does this large Exactrix application uniformity advantage mean relative to yield when growers are striving to maximize fertilizer use efficiency?   The inference from the study summarized below is that Exactrix application uniformity can provide a yield advantage of several bushels per acre compared with application uniformity provided by conventional anhydrous ammonia and granular fertilizer systems.   This is in addition to improvements in yield and fertilizer use efficiency related to co-injection of N, P, K, and S vs. surface application, especially in no-till systems


There are few studies that have measured effects of fertilizer application uniformity or non-uniformity on yields in the field.  Some theoretical studies show little effect of non-uniform fertilizer application on yields but more credible evidence is provided from actual measurements in the field.  Kansas State University conducted a field study comparing corn yield with two anhydrous ammonia application systems, one with a CV of 19% and one with a CV of  9% as determined in a stationary test (5).  Test results from the stationary systems with ammonia captured in water cans are presented in Table 1.  The stationary system with a 19% CV used a commercial variable diameter orifice (VDO) controller and the stationary system with 9% CV used a prototype pulse width modulation (PWM) controller.  In addition to giving less uniformity of distribution among openers, the VDO controller under-applied ammonia on average (22.3 vs. 27.0 lb ammonia per opener during the stationary test.  This was corrected for the plot studies.  


In a field trial, plots 8 rows wide and 400 ft. long were established with no N applied and with 120 lb N/Ac applied at V8 stage using the DVO and PWM controllers.  Soil ammonium N + nitrate N levels were measured soon after application at four 30-foot intervals along each opener path.  Grain yield was also measured based on three mature plants collected near each soil sampling site.  

Soil ammonium N + nitrate N levels are presented in Table 2.  The CV for soil ammonium N + nitrate N from the VDO controller was 55.6% vs. 16.8% from the PWM controller and the ranges were 22 to 216 ppm from the VDO controller and 61 to 140 ppm from the PWM controller.  This is much greater variability than measured in the stationary applicator tests.  This likely is due partly to greater application variability with a mobile applicator and partly to variability in soil N levels.


Grain yield was not nearly as variable as the soil ammonium N + nitrate N levels (Table 3).  This is likely due to roots from individual plants exploring a large enough area to take up N from soil supplying differing amounts of N and providing some averaging across soil N levels.  Even so, the yield CV was 17.2% for the DVO controller and 12.2 % for the PWM controller.  The yield range was 102 to 186 bu/Ac for the DVO controller and 120 to188 bu/Ac for the PWM controller.  More importantly, the average yield based on the three plant samples near each soil sample location was 149.4 bu/Ac for the DVO controller and 154.5 bu/Ac for the PWM controller.
 In another field trial, ear leaf N at silking and grain yields were determined based on whole-plot measurements (Table 4).  Treatments included no applied N, and N applied with VDO and PWM controllers at 60 and 120 lb N/Ac.  At the 120 lb N/Ac rate, grain yield with the PWM controller was 9 bu/Ac higher than with the VDO controller.  At the 120 lb N/Ac rate, ear leaf N was 0.38 percentage points higher with the PWM controller than the DVO controller.  There was clearly significantly more N available to plants with the PWM controller than the DVO controller. 

What do these results imply for yield benefits from Exactrix application uniformity?  Keep in mind that conventional anhydrous ammonia and granular fertilizer application systems have CVs of around 20% or higher and are expected to perform roughly the same or worse than the DVO controller in terms of uniformity of application.  Alternatively, Exactrix systems have CVs between 1 and 3% and are expected to perform better than the PMW controller in the study summarized above.  Furthermore, Exactrix systems are not adversely affected by changes in factors such as environmental conditions, field slope, field roughness, and granule properties.  Therefore, the yield advantage from Exactrix application uniformity is projected to be greater than the yield difference for the two ammonia systems in the study summarized above.   The inference from the study summarized above is that when producers are striving to maximize fertilizer use efficiency, Exactrix application uniformity can provide a yield advantage of several bushels per acre compared with application uniformity provided by conventional anhydrous ammonia and granular fertilizer systems.   

Don’t forget to add application uniformity to your list Exactrix benefits when calculating your bottom line.  Plant roots and nitrogen mobility can provide some “averaging” to partially compensate for non-uniformity of fertilizer application; however, Exactrix systems can provide significant yield increases related to better application uniformity than provided with conventional anhydrous ammonia and granular fertilizer application systems.  This is in addition to improvements in yield and fertilizer use efficiency related to co-injection of N, P, K, and S vs. surface application, especially in no-till systems.



1.  1. Development of a uniformity controlled granular fertilizer spreader. 2006.

1.    2. Distribution pattern variability of granular VRT applicator. 2005.

2.  3. The effect of fertilizer particle size on spread distribution. 2001.

3. 4. Pneumatic fertilizer spreaders—a review of the literature. 1990.

4.  5. Effects of uniform anhydrous ammonia application on corn growth. 1998.  

Bert R. Bock, Ph.D
Senior Advisor, former TVA soil scientist/fertilizer technologist

TAPPS and TAPPKTS with Hydra Hume Goes To The Next Level Of Performance.

Tri-Ammonium Poly Phosphate Sulfate

Stabilized nitrogen, triple super ammoniated phosphate with a sulfur source.
A polymer, crystallized, homogeneous nutrient manufactured with Exactrix process management. Outstanding performance of N,P and S.

The most available form of commercial plant nutrients. Stabilized nutrients, triple ammoniated.

An above ground test at the initial startup was used to confirm that the 2KC and 2KP systems were operational.

The 2KC NH3 system was bled, chilled and filled following NH3 safety protocol.

The 2KP APP/ATS delivered the material in a high quality stream flow. Triple super ammonization assured the crystal material with inter-mixing.

        Guy J. Swanson
Historically speaking Leonardite (Hydra Hume) has been in use for 30 years.

With Exactrix TAPPS and TAPPKTS  corn, wheat and cotton producers can expect additional net returns of 4% to 10%....that is a lot of money in irrigated corn.

Hydra Hume works very well with APP. It is a good player providing many more exchange sites to improve P uptake and N is much more efficient due to higher CEC. K efficiency is also improved and Zinc and Copper also perform better since they are not tying up in the soil calcium.

Historically Exactrix producers are finding up to $150 more net income after the product is paid $8.00 to $9.00 per gallon...about 1 gallon is used per 30 gallons of TAPPS, or TAPPKTS...NH3 plus APP,ATS, KTS and Zinc.  

Producers with irrigated corn can expect about $16.00 per acre of investment in Hydra Hume.  Dryland wheat is between $4.00 to $8.00 per acre. Irrigated wheat is about $16.00 per acre. Cotton is about $8.00 per acre.

It has been proven to be effective in irrigated high value crops in Washington and California.

It is now very effective in irrigated corn, Nebraska, Kansas and Colorado.

Helena Chemical is the market maker assuring the highest quality product.

If you have plans to use the material you should contact Helena Chemical at the wholesale level or the retail level. Helena will sell Hydra Hume to your fertilizer dealer.

You will want success the first time. Therefore Helena will be involved.  Do not shortcut since we have only had the best of luck with Helena Chemicals, Hydra Hume, 0-0-1, 12% Humic.

Exactrix will pay for all STEEP test plots.

Exactrix will require consistency in the plots and therefore application rates will be determined by Exactrix in plots.

You can also move your understanding of the Leonardite (Hydra Hume) further ahead by renting a third product formulator from Exactrix. Control is GS-3 or GS-2 or Trimble…or any other Can-Bus system. TASC 6200 can also be used with a TASC 6100.

Rental of the 2KS system is combined with and timed to the 2KP or the 2KM. The 2KS system injects at the 2KP or 2KM at the BPOR in a mixer, high turbulence chamber just before entering the accumulator manifold...the Hydra Hume material is short term delivery of two seconds to the injection point. The bypass return is back to a 100 gallon tank.

The 2KS also keeps other materials that may not be compatible with APP.ATS.KTS in the tank...but short term compatible at the injection point. Ammoniated Copper, Ammoniated Zinc, Oil of Essex.

The 2KS system allows producers to experiment with the third product in a Ramp Up design in each field.

Quick and very visceral plots are developed with the Ramp Up design...using Yield monitors...the data is not published. The Ramp Up allows producers to fine tune the product to their crops and soil types.

Good News...Finally a friend for Leonardite (Hydra Hume). TAPPS and TAPPKTS makes this material work with uniformity of Exactrix. Triple Super Ammonization makes Hydra Hume and Poly Phosphate work to performance levels that have never been observed in Exactrix Banding. APP, ATS, and KTS rates need to reviewed due to the high crop availability

Guy Swanson.

                                       Cross Row Feeding


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