The role of biological nitrogen fixation on crop productivity, nitrogen use efficiency and nitrous oxide emissions in reconfigured crop rotations. Quantification at different spatio-temporal scales

About Daian

Daian is an Agricultural Engineer from the University of Entre Rios (2017) and Graduate Research Fellow at the National Research Council (CONICET), Argentina. He has worked on numerous projects related with GIS programs, satellite imagery and geo-spatial databases. During the last years, he worked processing geo-spatial crop and soil information for several public organisations in the Argentinian agri-food sector. He is doing a PhD in Agricultural Sciences and currently, Daian is a teaching assistant of the Business Planning and Management course at FCA, University of Entre Rios.

Contact: [email protected]

About the project

The current crop sequences in the Argentinian Pampas are mostly based on soybeans as the only crop in the year. This configuration results in high Nitrogen Use Efficiency (NUE) due to the Biological Nitrogen Fixation (BNF) of soybeans and the low use of nitrogen fertilisers in cereals. However, this crop configuration compromises ecosystem services and generates dis-services that reduce the system sustainability and generate growing concern in society that show the need to design new crop sequences. In this project, we propose to contrast the soy-centric model with reconfigured sequences based on three elements: (i) double crops (winter crops and summer crops with different combinations of cereals and/or legumes), (ii) winter legume cover crops and (iii) a higher proportion of cereals. This higher proportion of cereals in the alternative sequences implies a higher requirement of N fertilisers, which could reduce NUE, and a greater potential to increase Nitrous oxide (N₂ O) emissions, a gas with a powerful greenhouse effect. To neutralise this situation, the alternatives crop sequences include winter legumes that contribute to BNF, and corn, a highly efficient cereal intrinsic in the use of N. This project addresses problems at different scales: a) at the plant and crop scales, the potential reduction of BNF due to the higher frequency of hypoxia and higher temperatures associated with climate change; b) at the farm (paddock) and regional scales, unreliable methods for quantifying and modelling emissions of N₂O and BNF, and c) at the regional scale, the uncertainty due to the effects of climate change on the stability of yields, and the N balance components in the long-term. The general objective of the project is to compare the dominant soybean-centric sequence in the Pampas region with alternative crop sequences, with a primary focus on BNF and its relationship with grain production, NUE and N₂ O emissions. To achieve this objective we propose an approach at different spatio-temporal scales, from short-term physiological processes in the plant to the long-term regional level where the environmental impacts associated with the N economy are manifested in future climatic conditions. To capture this range of scales we designed a project that complements: (i) experiments in controlled conditions (glasshouse) and field experiments; (ii) climate change projection models and crop simulation models coupled using geographic information systems and remote sensing products; (iii) updated theories and specific hypotheses for each component of the project, and (iv) a scientific team with proven knowledge of the production systems under study and with a diversity of perspectives.

Location

FCA, University of Entre Rios, Argentina

Period

2021-2026

Supervisors

Dr Caviglia Octavio (FCA, University of Entre Rios, Argentina), Dr Victor Sadras (PIRSA-SARDI, Australia) and Dr Jonathan Ojeda (QAAFI, The University of Queensland, Australia)