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When considering a nitrogen management plan, the topic of nitrogen stabilizers can be complex and confusing. With so many options available, and many variables including weather, soil and cost factors in play, it can be difficult for you and your farmers to decide what solution makes the most sense for their operation. Optinyte™ (nitrapyrin) and DCD (dicyandiamide or N-cyanoguanidine) are two of the most common options for below-ground nitrogen protection, but they both serve different and very specific purposes. These technologies are vastly different in chemical composition, and some DCD products have complicated and even misleading claims, making the category difficult to navigate.
Deciding which nitrogen management technology to select is a critical choice for you and your farmers. Here, we’ve broken down the two most common options:
Optinyte™ (nitrapyrin). Optinyte™ technology, which includes the active ingredient nitrapyrin, is a nitrification inhibitor that slows the conversion of ammonium nitrogen to nitrate nitrogen. It does so by inhibiting the activity of Nitrosomonas bacteria present in the soil (meaning it is bacteriostatic), which causes this nitrogen conversion. This process is significant because although corn uses nitrogen in both forms, it prefers ammonium as it is more efficient for plants to use and less susceptible to loss via leaching and denitrification. Optinyte™ is the active technology that powers Instinct® and N-Serve® nitrogen stabilizers and it has been proven for more than 40 years to effectively inhibit nitrogen loss.
DCD (dicyandiamide). DCD is also a nitrification inhibitor that has a bacteriostatic effect on Nitrosomonas bacteria. Like Optinyte™ technology, DCD aims to prohibit the conversion of ammonium nitrogen to nitrate nitrogen and consequential loss through leaching and denitrification.
Key differences you need to know. Although these two technologies both inhibit nitrification, they are vastly different in how they are used on an operation and the results they deliver:
As soil temperatures rise above 40 F, nitrogen is susceptible to loss via nitrification, with accelerated loss occurring in temperatures above 65 F. Studies show that in warm soils, Optinyte technology can last up to eight weeks, while DCD lasts approximately 7 to 14 days in the soil at 70 F.[1] Crops have the best chance for proper nitrogen uptake with Optinyte because it keeps nitrogen in the soil up to eight weeks, at least four times longer than DCD.
University trials indicate the effect of Optinyte technology on grain yield represents a relative yield increase of 7%.[2] Research on the impact of DCD on yield shows no benefits.[3]
Optinyte technology use rates are based on acres of land treated, rather than amount of fertilizer used. For example, approximately 1 quart of Optinyte technology is used per acre versus 10 gallons of DCD technology used per ton of fertilizer. Optinyte is proven to be effective, even at low rates, and DCD requires a higher application rate to be effective.[4]
Optinyte technology was awarded the Presidential Green Chemistry Challenge Award for its reductions in carbon dioxide emissions over the years. The technology added about 50 million bushels of corn and reduced carbon dioxide emissions by about 664,000 metric tons.[5] The environmental benefits of DCD are still being debated by peer-reviewed publications.[6]
DCD is water soluble and can leach away with the first significant rainfall event in contrast to Optinyte technology, which remains in the root zone protecting nitrogen from losses.[7] DCD has also been proven to cause plant injury to corn, wheat and other commonly grown crops, whereas Optinyte has shown in university research and trials to not cause plant injury.
These key differences highlight significant considerations for farmers as they evaluate and create their nutrient management plans. The most significant factor is length of control. DCD can be less than ideal for Midwest corn growing states due to its sensitivity to warm temperatures. If farmers are looking for a product that is less sensitive to warm temperatures and offers a great deal of persistence in cool soils, Optinyte technology is a better option.
Other considerations, like proven yield increases, environmental factors and rate of application, depend on the farmer’s preference for research-proven claims and the amount of involvement they like to have with mixing and blending product during application.
When reviewing the nitrification inhibitor options available, it can be difficult to know which product makes the most economic, environmental and logistical sense for your farmers’ operation. DCD’s effective activity time is shorter than Optinyte, despite also being a nitrification inhibitor. Because Optinyte protects nitrogen for longer period during critical corn growth stages, and it has more environmental and research-backed benefits, it makes for a more effective nitrogen stabilizer for farmers looking for a longer-term and more stable solution.
For additional resources and information on the differences between Optinyte technology and DCD, please contact your territory manager or refer to the Max Facts Q&A page.
[1] Bronson, K. F., J. T. Touchton, and R. D. Hauck. 2008. Decomposition rate of dicyandiamide and nitrification inhibition, Communications in Soil Science and Plant Analysis, 20: 19-20, 2067-2078, DOI.: 10.1080/00103628909368201
[2] Wolt, J. D. 2004. A meta-evaluation of nitrapyrin agronomic and environmental effectiveness with emphasis on corn production in the Midwestern USA. Nutr. Cycl. Agroecosyst. 69: 23–41. doi:10.1023/ B:FRES.0000025287.52565.99.
[3] NutrientStar. DCD Research Findings. http://nutrientstar.org/tool-finder/dcd-research-findings/
[4] Mullen, Robert W. 2010. Nitrogen additives: What is what, and do they work?” Proceedings of the Integrated Crop Management Conference. 23. https://lib.dr.iastate.edu/icm/2010/proceedings/23
[5] Environmental Protection Agency. Presidential Green Chemistry Challenge: 2016 Greener Reaction Conditions Award. www.epa.gov/greenchemistry/presidential-green-chemistry-challenge-2016-greener-reaction-conditions-award
[6] Yang, M., Y. Fang, D. Sun, and Y. Shi. 2016. Efficiency of two nitrification inhibitors (dicyandiamide and 3,4-dimethypyrazole phosphate) on soil nitrogen transformations and plant productivity: a meta-analysis. www.nature.com/articles/srep22075.pdf
[7] McCarty G. W., and J. M. Bremner. 1989. Laboratory evaluation of dicyandiamide as a soil nitrification inhibitor. Comm Soil Sci Plant Anal. 20: 2049-2065.5