1. University of Florida stuides have demonstrated that the P in Milorganite is both plant available, and subject to much less leaching than P in triple super phosphate (TSP), a common P source in mineral fertilizers.
While Phosphorous (P) in run-off contributes to algae growth in lakes and streams, Milorganite has been exempt from numerous state P bans because it is considerably less likely to leach than chemical or synthetic fertilizers.
What is the role of Phosphorous (P)?
Phosphorous plays an important role in the photosynthesis process; essentially it helps the plant “breathe.” Phosphorous aids in energy transfer and storage and helps plants efficiently use water. Phosphorous is associated with root development and plants grown in soils lacking the proper amounts of P will not likely produce fully developed root systems.
Phosphorous also plays a significant role in maintaining a healthy lawn, and a healthy lawn plays an even bigger part in keeping our waterways clean. A thick, lush lawn acts as a filtration system cleaning and purifying water before it runs into our lakes. Research shows that lawns fertilized with P contribute less run-off than lawns that have not received any applications at all.
Research indicates that Milorganite provides phosphorous, an essential nutrient for plant growth, without the leaching that is typical of mined phosphorous sources.
Research conducted by University of Florida compared Milorganite phosphorous to other fertilizer P sources. The research showed that the leaching potential was greater with the synthetic fertilizer sources, and that Milorganite’s slow release P source provides sufficient amounts of P for plant growth, with very little P leaching. This same research states that “Less than 20% of the total P applied leached for nitrogen based Milorganite treatments, suggesting that most Milorganite P is ultimately insoluble and will not leach.”
The phosphorous in Milorganite is slow release, available to the plant as the plant requires it in adequate (but not excessive) amounts, therefore, making it less likely to leach. Naturally occurring P is typically chemically bound up in the soil and not available for plant uptake. Research indicates that naturally occurring phosphorus “binds” to the Milorganite and in turn becomes more readily available for plant uptake, and less likely to leach into rivers, lakes, and streams.