Nitrogen utilization (15 N) by sugar cane from spraying foliar (n-urea) as a supplemental application of nitrogen

• Grant number: 20/07936-5
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2020
• Effective date (End): February 28, 2022
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal researcher: Paulo Cesar Ocheuze Trivelin
• Grantee: Régis Ricchini Leite Vieira
• Home Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The efficiency of use of fertilizer nitrogen (EUN) applied to the leaves of sugar caneis high, reaching 85% when compared to the EUN applied to the soil, an average of 25%.Currently, of the total nitrogen applied to the crop's stalk, about 32% is immobilized byorganic matter and only 25-26% is absorbed by the plant, which demonstrates the lowefficiency of the use of N by sugarcane (Otto et al., 2016). Nitrogen that is not absorbedcan be lost in the environment, mainly by leaching, runoof, denitrification volatilizationand NO3- and NO2- emission through the leaves (Cantarella et al., 2007; Otto et al., 2016;Robinson et al ., 2013) The application of N in the leaves of sugarcane contributes to thereduction of nutrient losses, but due to the importance of N-fertilizer in the beginningof the regrowth of sugar cane, nitrogen fertilization in the soil, even if in a lower dose ofthe nutrient when using foliar fertilization management with N. In this context, theobjective is to evaluate the EUN applied in two doses (0.075 and 0.15 g of N per plant);equivalent, in the field, to doses of 5 and 10 kg ha-1 of N) in the upper leaves ofsugarcane, as a complement to nitrogen fertilization in the soil in an experiment in agreenhouse. The experiment will be installed with a randomized block design in a triplefactorial scheme 2 X 2 X 3. The first factor will be composed of the N-leaf doses, thesecond factor will correspond to two doses of N in the soil (ideal nitrogen dose in thesoil, 286 mg dm3, and 20% of the ideal dose of N in the soil, about 40 mg dm3) and thethird factor will represent three methods of application of N in the leaves of the crop inorder to compare the methodology used in other experiments . To perform thisexperiment, three repetitions will be used.