BEST MANAGEMENT PRACTICES

Editor ’ s Note : The following nutrient management best management practices are excerpted from SFMA ’ s National BMP guide , Best Management Practices for the Sports Field Manager : A Professional Guide for Sports Field Management . The full guide , as well as a customizable BMP template , is available at https :// www . sportsfieldmanagement . org / knowledge _ center / bmps /

For the first part of the BMPs for Nutrient Management , please see the January 2023 issue of SportsField Management magazine or refer directly to the SFMA BMP guide .

“ NATURAL ” AND “ ORGANICALLY CERTIFIED ” FERTILIZERS In some cases , communities or organizations require / prefer to use “ natural ” and / or “ organically certified ” fertilizers . However , these terms are often the subject of misinformation . It is important to realize that , despite popular opinion , these are not necessarily healthier with respect to human health . For example , arsenic is a natural compound , yet is highly toxic to humans .

In terms of plant nutrition , an atom of a nutrient is chemically identical regardless of source . For example , the fertilizer with greatest volume of use is urea . It is manufactured using nitrogen gas from the atmosphere that is converted to ammonia using natural gas in the Haber-Bosch process , which is then combined with carbon dioxide . The nitrogen in this and the urea molecule itself are identical in every way to the urea that is naturally produced in animal livers . Either source is beneficial to plants and pose no risk to plants or animals ( including humans ) when used properly . However , manufactured urea requires the use of non-renewable resources . Conversely , low nitrogen analysis fertilizers require more fossil fuel use for transportation in order to supply the same amount of nitrogen ( e . g ., urea is 46 % nitrogen , whereas most of these alternative fertilizers are less than 10 % nitrogen ). Regardless , demand for these products exists and it is important to understand their properties and the management practices needed for their proper use .

The nutrients in any fertilizer , including natural and organically certified fertilizers , must be factored into the overall nutrient management planning . In addition , some regulatory requirements ( e . g ., phosphorus prohibitions ) must be adhered to regardless of fertilizer source .

Labeling of fertilizers as “ natural ” is not subject to regulatory oversight . The definition is “ existing in or caused by nature .” In reasonable consideration , so-called natural fertilizers tend to include protein-rich plant or animal wastes . These tend to have the benefit of including a broad spectrum of nutrients that are generally released slowly , mostly during the summer when temperatures drive high decomposition rates . These materials tend to have high carbon content , which can be beneficial if organic matter building of the soil is desired . This is typically helpful , although not in sand-based fields where excessive organic matter can result in reductions in drainage and increased compaction potential . Some of these materials , especially those with high fiber content , can be a source of pathogen stimulation . Typically , the main disadvantage is that the low concentration of mineral nutrients in these sources correlates to higher costs of the fertilizer , as well as transportation , storage and application . Many sources of these materials exist , such as : Animal manures ( uncomposted and composted wastes ). Animal industry byproducts ( bone , blood , feather , fish , etc ., meals ). Green manures ( plant-based composts ). Liquid cocktails ( manure extracts , seaweed extracts , compost teas , etc .).

By contrast , “ organically certified ” fertilizers are any materials approved by the Organic Materials Review Institute ( OMRI ). These can include any of the products listed previously , including those that are derived from carbon-based materials , typically animal and plant waste materials , but also can include inorganic salts ( e . g ., calcium carbonate , calcium sulfate , potassium sulfate ) and many other materials . OMRI certifies products rather than providing generic certifications for chemicals . For example , one potash source may be certified for organic use after the review and labeling process while another , despite being chemically identical , will not be certified for organic use if it has not gone through the certification process .

Sports field managers should carefully review and evaluate each commercial product before use . Because considerable variation exists in the physical and chemical properties of the various fertilizers , they should be carefully evaluated when used as part of a nutrient management

12 SportsField Management | February 2023 sportsfieldmanagementonline . com