Evaluation of Foliar-Applied Nano-Fertilizers for Enhanced Nitrogen Use Efficiency in Wheat

Evaluation of foliar-applied nano-fertilizers for enhanced nitrogen use efficiency of wheat Hanna Poffenbarger, Jason Unrine, Olga Tsyusko, and Leticia Pacheco Inoue Nitrogen fertilization is often necessary to raise a productive, profitable, and high-quality wheat crop. However, nitrogen fertilizer inputs can contribute to environmental degradation. Nitrate compromises drinking water quality and contributes to toxic algal blooms and dead zones. In addition, microbial transformations of fertilizer nitrogen produce nitrous oxide, a powerful greenhouse gas. Finding ways to manage nitrogen efficiently - so that more of it ends up in the crop and less in the environment- is crucial to maintaining a nutritious and secure food supply while improving environmental quality. Farmers have options in terms of the nitrogen fertilizer source that they use and how it is applied to wheat. Two common nitrogen fertilizer sources are urea and urea ammonium nitrate (UAN). The former is typically soil-applied, while the latter may be applied to the soil or to the foliage. It is not well understood how the nitrogen source (urea vs UAN) and delivery method (soil vs. foliar applied) impact nitrogen use efficiency, nitrate leaching, and nitrous oxide production in Kentucky wheatfields. However, because soil microbes are responsible for nitrate and nitrous oxide production, it stands to reason that applying nitrogen fertilizer to the leaves rather than the soil could decrease these losses. There are also novel fertilizer products, specifically nanocarriers, which are thought to enable more efficient uptake of nitrogen by plant leaves. The goal of this study is to assess the nitrogen use efficiency and environmental impacts of foliar nitrogen application with and without nanocarriers. We propose a field study that includes the following treatments: Source Application Application Treatment type method details UAN Soil-applied Streamer nozzle Conventional UAN Foliar applied Broadcast nozzle Conventional UAN with nanocarrier* Foliar applied Broadcast nozzle Farmer-ready nano-fertilizer Urea granules Soil-applied Broadcast Conventional Urea solution Foliar applied Broadcast nozzle Conventional Urea solution with Foliar applied Broadcast nozzle Experimental nano-fertilizer nanocarrier* *The nanocarrier for UAN will be the commercially available Aqua Yield NanoN+ product, which is thought to provide faster uptake of nitrogen into cells. The nano-carrier for urea will be zinc hydroxyapatite, which is thought to provide a slow-release form of urea. In this study, the fertilizer will be split-applied with 30% applied at Feekes 3, 50% at Feekes 5, and 20% at Feekes 8. We plan to impose these treatments at four rates (0, 60, 120, and 180 lb N/acre). Using the yield response to nitrogen, we will test the hypothesis that foliar application enables higher yields with less nitrogen fertilizer, and that this improved nitrogen use efficiency is further enhanced by nanocarriers. We will monitor leaf burn for possible negative effects of foliar application. We also plan to measure the nitrous oxide emissions and nitrate leaching of each treatment at a single nitrogen rate (120 lb N/acre). Due to the laborintensive nature of nitrous oxide emissions, we plan to conduct this study only at Spindletop Farm. Our budget includes $6,238 for a part-time student worker who will perform field sampling, laboratory analysis, and contribute to plot maintenance. We also request $2,000 for laboratory supplies and analysis costs. The total budget request will be $8,238.