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Nitrogen (15N) use efficiency for fertilization managements of maize and common bean using mixtures of polymer sulfur coated urea and conventional urea

Grant number: 17/25813-5
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): April 01, 2019
Effective date (End): June 30, 2020
Field of knowledge:Agronomical Sciences - Agronomy - Soil Science
Principal Investigator:Paulo Cesar Ocheuze Trivelin
Grantee:Pedro Lopes Garcia
Home Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil


Nitrogen (N) is the most required nutrient by maize and common bean, being necessary in low quantities at the beggining and in adequated quantities during the development of both crops. Urea is the main N source but it has a low N Use Efficiency (NUE) that is associated with N losses when this source is applied on the soil surface. A manner to increase NUE would be to use mixtures of polymer sulfur coated urea (URSP) and conventional Urea (U). However to recommend accurately these mixtures in the current cropping systems, it is necessary to know the participation of each source of the mixture (U+URSP) in the uptake by the plants. Therefore, it is necessary to label each fraction of the mixture (U+URSP) with 15N isotope. Thus, the main objective of the present work is to evaluate the N fertilizer use efficiency (NUEF) by maize and winter common bean, applying mixtures of U+URSP (15N-labelled) on certain straw immediately after sowing in no tillage. The specific objectives will be to evaluate in field experiments: a) NUEF by maize and winter common bean; b) the nitrogen (15N) in plants from the fractions of the mixtures (U+URSP) during the maize and commom bean cycle; c) residual nitrogen (15N) in the soil at the end of the crops cycles; d) NUE using the difference method; e) dry mass and macronutrients accumulation of the aerial part of plants during the crops development; f) the maximum rate of dry mass and macronutrients accumulation; g) the mineral N of the soil along the crops cycles; h) C/N ratio and amount of straw produced by the previous crop; i) fertilizer ammonia volatilization; j) grain yield. (AU)