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Fluid Journal : Spring 2011
12 The Fluid Journal Spring 2011 Studies are mixed indicating more work needs to be done in this area. Do Fertilizer Additives Help In Increasing Root Mass and Yields? The Fluid Journal • Ofﬁcial Journal of the Fluid Fertilizer Foundation • Spring 2011 • Vol. 19, No. 3, Issue #73 Dr. R. W. Heiniger Summary: Over a period of three years, five individual studies evaluated the effects of the fertilizer additive AvailTM on corn root growth and stalk diameter while the effect of the additive on corn grain yield was evaluated for eight site-years. There were no significant differences at the 5 percent level in root ball depth or width due to inclusion of the additive with starter fertilizer, although relatively consistent numerical differences were measured. However, root mass was significantly increased in two of the five site years. Additionally, the use of the additive significantly increased stalk diameter in three of the five site-years. Corn grain yield was increased in five of the eight site-years with the addition of the additive to the starter fertilizer, although the difference was statistically significant at the 5 percent level at only one site. However, when averaged across all site years, the additive significantly increased corn yield when compared to the use of starter fertilizer alone. In other studies, while significant location-by-nitrogen (N) rate and timing-by-NutrisphereTM additive interactions were measured, the addition of the additive to UAN solution resulted in a significant yield increase of 0.74 t/ha-1 compared to UAN alone. Additionally, there was a significant yield increase (p = 0.0152) of 0.93 t/ha-1 resulting from the use of the additive whenever starter fertilizer was applied (either 12-12-4 or 12- 12-4 with AvailTM). Two new fertilizer additives recently released have the potential to increase nitrogen (N) and phosphorus (P) concentrations in the root zone, reduce leaching of these nutrients, reduce volatilization losses of N, and decrease P fixation in the soil resulting in a better match between the availability of N and P and crop nutrient demand when compared with conventional fertilizers. AvailTM and NutrisphereTM are both long-chain branched polymers with a large negative charge (1,800 meq 100 g-1). This charge makes the molecule stable at high ionic concentrations, allowing it to hold other molecules in suspension. When Avail is added to either a liquid or solid phosphate fertilizer and applied to the soil the negative-charged polymer interacts with positive cations such as Ca++ and Mg++, preventing them from interacting with and fixing phosphate. Likewise, when added to urea and/or ammonium containing or forming fertilizers, it is thought that the polymer reacts with multivalent cations that are required by the urease enzyme and/or soil microbes involved in nitrification. While comparative research on corn performed at Kansas State University, the University of Illinois, and other institutions indicates that each of these additives improved crop yield on a wide variety of soil types, other studies have not found improvements in yield or nutrient use efficiency (NUE). Clearly, more information is needed to determine when each additive is most effective in increasing plant growth, yield, and fertilizer use efficiency in highly productive cropping systems. The objectives of this research are to: • Examine the impact of the fertilizer additives on yield in high population corn systems
Early Spring 2011