Root C and N distribution on the soil under maize-brachiaria intercropping

• Grant number: 17/14895-0
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): October 01, 2017
• Effective date (End): August 14, 2018
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Heitor Cantarella
• Grantee: Rafael Domingues de Oliveira
• Home Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil
• Associated research grant: 15/50305-8 - A virtual joint centre to deliver enhanced nitrogen use efficiency via an integrated soil-plant systems approach for the UK & Brazil, AP.TEM

Abstract

Increasing Nitrogen Use Efficiency (NUE) is critical so that agricultural production move along three important aspects: food security, environmental degradation and climate change. One technique that has been calling attention of Brazilian producers is intercropping grains with tropical forages. This cropping system highlight is the most efficient use of N, however, the mechanisms that make it more efficient have yet to be studied and tested. This project is part of a doctorate thesis linked to NUCLEUS, a FAPESP project (15/50305-8), which is looking to relate NUE to the volume of soil that is explored by the plants in intercropping systems. The intercropping system chosen to be tested on this project is maize-brachiaria. The hypotheses of this research are that intercropping maize and brachiaria raises NUE and brachiaria root volume during winter on the superficial soil layer. Part of the organic N from the roots will then be available to the following crop. This project aims to evaluate NUE, roots biomass, C and N roots content on sole maize and maize-brachiaria intercropping, correlating the NUE with roots volume and N content. Treatments (6), distributed in randomized blocks, consisted of plant combination and N rates ( 0 or 150 kg N ha-1) top dressed at the 4-leaf stage: maize + 0 kg N ha-1 (M0), maize + 150 kg N ha-1 (M150), maize-brachiaria brizantha + 0 kg N ha-1 (MB0), ), maize-brachiaria brizantha + 150 kg N ha-1 (MB150), maize-brachiaria humidicola + 0 kg N ha-1 (MH0), maize-brachiaria humidicola + 150 kg N ha-1 (MH150). The results of this project seek to evaluate if maize intercropped with Brachiaria humidicola and Brachiaria brizantha increase NUE and roots volume on the soil compared to sole crop system, as well as a comparison of the amount of N on the roots of both systems. (AU)