What’s the difference between Nature Safe and other organic fertilizers such as Sustane and Milorganite? There are many differences between them, but many, such as higher protein content, are difficult to quantify in terms the user understands. The adjacent comparison of amino acid profiles will help you to understand this.
In any organic fertilizer, the slow release nitrogen comes from proteins, which are made up of amino acids. Therefore, the more amino acids in an organic fertilizer, the more slow release nitrogen it can provide. The numbers listed on the comparison page are all percentages. The totals on the bottom of each column are for the amino acids only. As you can see, Nature Safe contains nearly five times more amino acids than Sustane and twice as many as Milorganite. It should be noted that the reason Milorganite shows up as good as it does is that it contains no potash. Potash contains no amino acids, so if you add it to an organic product like Nature Safe 10-2-8, the percentage of amino acids in the end product is lowered. If we did not put potash into 10-2-8, it would test out at 80% amino acids, and if Milorganite were to add potash to their product, it would drop to about 20% amino acids.
An amino acid profile only can tell us how much slow release nitrogen is in a particular product. It does not address the nitrogen availability. Availability is a function of how easily the soil microbes can digest the proteins contained in an organic fertilizer. We know that all of the proteins in Nature Safe are very digestible. However, the proteins in Milorganite, due to the high heat process used, become very difficult for the soil microbes to digest. Dr. Wayne Kussow, University of Wisconsin has reported he could only get 47% of the nitrogen in Milorganite to release.
The ash contained in organic fertilizers has been implicated in the plugging of pore spaces in the soil and the reduction of infiltration rates. Some ash is unavoidable (ash represents everything that is not organic, so potash and other minerals are part of this), but you will notice that Sustane is 45.54% ash, nearly double the amount contained in Nature Safe. Since the Sustane is a 5-2-4 and Nature Safe is a 10-2-8, twice as much Sustane is needed to apply the same amount of nitrogen. That means you would be applying nearly four times as much ash with Sustane in order to apply the same amount of nitrogen per unit area. That certainly should be cause for concern.
This comparison is a great way to explain how Nature Safe is different than a composted or a sludge product while emphasizing the fertility value Nature Safe has to offer. If you have further questions concerning this information, please contact your Nature Safe Professional.