Nitrogen use efficiency as an indicator for monitoring the environmental sustainability of maize production in central Chile

Osvaldo Salazar1, Ricardo Cabeza1, Yasna Tapia1, Claudia Rojas1, Carla Soto1, Miguel Quemada2, Manuel Casanova1

1 Departamento de Ingeniería y Suelos, Facultad de Ciencias Agronómicas, Universidad de Chile, Santa Rosa 11315, Santiago, postcode 1004, Email: [email protected]

2 Technical University of Madrid (UPM), Ciudad Universitaria, Madrid, 28040. Email: [email protected]

Abstract

The main purpose of this study was to evaluate the Nitrogen Use Efficiency (NUE) as an indicator for monitoring the environmental sustainability of maize production in the O’Higgins Region in central Chile. Additionally the NUE indicator was used for evaluating the extension services offered for a Clean Agreement Program (CAP) developed for the Chilean Government for the maize-farmers in this Region. A crop management survey was carried out in 80 maize fields during the season 2014-2015, where most of the NUE values were less than 50% using traditional farmer N fertilisation rates, being related to N over-fertilisation. For the 2016-2017 season, 85% of the NUE values would be between the two NUE references values of 50% and 90% if a N recommendation scenario based on a mass N balance by the CAP is applied by the maize-farmers. Thus NUE showed that it is necessary to reduce the N input for improving the environmental sustainability of maize production in this Region.