The contribution of biological nitrogen fixation, mineral nitrogen fertilizer and soil nitrogen content to plant N-metabolism and soybean production

• Grant number: 17/17756-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2018
• End date: November 30, 2018
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: José Lavres Junior
• Grantee: Nícolas Braga Casarin
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Biological nitrogen fixation (BNF) is the main source of nitrogen (N) uptake and assimilation by soybean crop. The hypothesis to be verified is whether the mineral-N supply as fertilizer can halt nodulation and N-metabolism as well as reducing gains yield and shoot biomass. The objectives of this work are to evaluate the main effect of BNF, the application of mineral nitrogen at sowing, flowering and both times and quantify the soil-N supply in order to evaluate the amount of 15N taken up by plants from soil, fertilizer and the contribution of biological nitrogen fixation (BNF), by means of the isotope technique (´15N). In this sense, we will evaluate the plant nodulation, nitrogenase activity (EC 1.18.6.1) and nitrate reductase (EC 1.7.1.1), quantification of ureides in roots and stem, the fate of 15N redistribution (retranslocation), growth, biomass and grains yield. The fertilizer used (urea) will be enriched with the 15N isotope, at 5% excess atoms. Two cultivars of different growth types will be assessed in this study: one determined (BMX Active RR) and one indeterminate (BMX Elite IPRO/BMX Apolo RR). The experiment will be carried out in pots containing 10 dm3 of soil from a typical Red-Yellow Distrophic Latosol (LVAd), using the experimental design of complete blocks at random, with treatments arranged in a 4 x 2 x 6 factorial scheme (four forms of N-application x two cultivars x six times of evaluation), with three blocks. The variables of BNF quantification, 15N-remobilization, nitrate reductase and nitrogenase activities, ureides concentration in xylem sap, rate of assimilation of CO2, plant dry mass and N concentration, fresh mass and number of nodules and the protein: oil ratio in the grain will be also evaluated. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

CASARIN, Nícolas Braga. The contribution of different nitrogen sources to BNF and soybean N-metabolism. 2019. Master's Dissertation - Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) Piracicaba.