3/27/2024 - By Dr. Jeff Atkinson

POLYON® controlled-release fertilizer is a technology that can be mapped and tracked over the entirety of its release period. This is possible with Harrell’s POLYGRAPH which predicts nutrient release by analyzing your location’s historical data, application date, and rate, and your specific POLYON fertilizer blend. This tool is extremely useful for various reasons, which stem from the characteristics and uses of controlled-release fertilizer itself.

What is controlled-release fertilizer?

The Association of American Plant Food Control Officials (AAPFCO) defines a controlled-release fertilizer as, “a slow-release fertilizer that is engineered to provide nutrients over time at a predictable rate under specified conditions.” Two things about this definition stand out:

1.       “Engineered.”

2.       “Predictable rate under specified conditions.”

Turf management is increasingly data-driven. Inputs are planned, measured, and tracked in extreme detail. Therefore, a product that is engineered and provides nutrients over time at a predictable rate under specified conditions aligns with today’s emphasis on detail in turfgrass management and describes the unique characteristics of POLYON®.

Who Owns POLYON® Controlled-Release Fertilizer?

Harrell’s purchased POLYON® controlled-release fertilizer in 2019. With the POLYON® acquisition, Harrell’s gained ownership of technology, intellectual property, and manufacturing capability, as well as decades of dependable performance in the turf, ornamental, and agriculture markets.

Since 2019, Harrell’s has continued to invest in the people and equipment necessary to optimize the quality, consistency, and dependability of all POLYON® fertilizers. The acquisition and the continued investment are part of our commitment to ensuring that Harrell’s customers can benefit from the absolute best and most accurate controlled-release product.

Figure 1. Harrell's new state-of-the-art coating facility.

How is POLYON Controlled-Release Fertilizer Made?

Manufacturing POLYON® fertilizer is not as simple as spraying a polymer on a fertilizer substrate and calling it a day. POLYON® fertilizer manufacturing involves a specific recipe that intricately details the order in which, and speed in which, raw materials must be added to formulate a quality batch. Deviation from the recipe will result in material that does not provide the expected level of durability, consistency, or control. Any batch that does not meet the very high quality, uniformity, and formulation standards that we carefully monitor, with be rejected. There are no “bad batches” here per-se.

Three factors influence POLYON® nutrient release:

Soil Moisture

Briefly, if adequate soil moisture is available to facilitate healthy plant growth (unless you are fertilizing a cactus in the Mojave Desert), then enough soil moisture is available to facilitate POLYON® fertilizer nutrient release but keep note that more moisture does not increase release speed.

POLYON Coating Thickness

If all environmental factors are equal, POLYON nutrient release longevity is determined by coating thickness. Nutrient release longevity increases as coating thickness increases. The optimal coating thickness for every POLYON fertilizer product is developed by Harrell’s dedicated POLYON R&D team, manufactured following a proprietary processes, and monitored for adherence to POLYON quality standards through Harrell’s stringent quality control program. This approach ensures POLYON coating thickness is consistent from batch to batch, translating into predictable performance in the field.

Air Temperature

The wild card is air temperature. While we do not know what air temperatures will be in the coming days, weeks, or months, we do have a database of historical weather data. When averaged across time, historical weather data gives us a close enough indication of what to expect for temperatures in the future.

Harrell’s POLYGRAPH Technology and POLYON® Fertilizer

Harrell’s proprietary POLYGRAPH software can use mathematical models to predict the release of POLYON. Equipped with this information, turf managers can plan for the year, prep for tournaments, and time their nutrient applications.

Mathematical prediction models can be complex; however, we trust them every day. Weather forecasts are a good example. The estimated time of arrival in Google Maps is another. Considering the limited influence of moisture on POLYON® fertilizer’s release and the consistency of coating thickness, creating a model that predicts POLYON® fertilizer nutrient release based on averaged historical weather data is not far-fetched. In fact, it is utilized by turfgrass managers every day through our proprietary POLYGRAPH software.

Harrell’s POLYGRAPH is a digital tool available through your Harrell's Territory Manager. The POLYGRAPH predicts nutrient release from POLYON® fertilizer blends by considering the historical weather data of a geographic location for the period following your specific application date, components of the fertilizer blend, and application rate. Users are provided with an output that describes nutrient release from the POLYON® fertilizer blend every week for the duration of the blend’s longevity. Such detailed resolution is useful for several reasons.

Here are three ideas for maximizing the POLYGRAPH:

1.       Annual agronomic planning. Match fertility rate with desired growth objectives for specific time periods.

2.       Pre-tournament preparation. Plan for peak nutrient release in the lead-up to a tournament or plan for adequate nutrition post-tournament to encourage recovery.

3.       Time nutrient applications so the overlap of nutrient release is optimized between applications.

Figure 2. POLYGRAPH accurately predicts nutrient release based on application location, date, blend ingredients, and application rate. The POLYGRAPH above describes nitrogen release following the application of a POLYON mini blend at 1.5 lbs. N per 1000 sq. ft. on May 1st, 2024.

These are only a few ideas of how Harrell’s POLYGRAPH can benefit an agronomic program. Foliar liquid inputs are often calibrated to 1/100^th of a pound of nitrogen per 1000 sq. ft, shouldn’t we expect the same control from granular fertility applications? We think so.

Learn more about how the POLYGRAPH, paired with your perfect POLYON® controlled-release fertilizer blend, can change your turf.

Reach out to your Harrell's Territory Manager for a demo today!