Mechanistic framework to link root growth models with weather and soil physical properties, including example applications to soybean growth in Brazil

Moacir Tuzzin De Moraes (Lead / Corresponding author), A. Glyn Bengough, Henrique Debiasi, Julio Cezar Franchini, Renato Levien, Andrea Schnepf, Daniel Leitner

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)
189 Downloads (Pure)

Abstract

Background and aims: Root elongation is generally limited by a combination of mechanical impedance and water stress in most arable soils. However, dynamic changes of soil penetration resistance with soil water content are rarely included in models for predicting root growth. Better modelling frameworks are needed to understand root growth interactions between plant genotype, soil management, and climate. Aim of paper is to describe a new model of root elongation in relation to soil physical characteristics like penetration resistance, matric potential, and hypoxia.

Methods: A new diagrammatic framework is proposed to illustrate the interaction between root elongation, soil management, and climatic conditions. The new model was written in Matlab®, using the root architecture model RootBox and a model that solves the 1D Richards equations for water flux in soil. Inputs: root architectural parameters for Soybean; soil hydraulic properties; root water uptake function in relation to matric flux potential; root elongation rate as a function of soil physical characteristics. Simulation scenarios: (a) compact soil layer at 16 to 20 cm; (b) test against a field experiment in Brazil during contrasting drought and normal rainfall seasons.

Results: (a) Soil compaction substantially slowed root growth into and below the compact layer. (b) Simulated root length density was very similar to field measurements, which was influenced greatly by drought. The main factor slowing root elongation in the simulations was evaluated using a stress reduction function.

Conclusion: The proposed framework offers a way to explore the interaction between soil physical properties, weather and root growth. It may be applied to most root elongation models, and offers the potential to evaluate likely factors limiting root growth in different soils and tillage regimes.
Original languageEnglish
Pages (from-to)67-92
Number of pages26
JournalPlant and Soil
Volume428
Issue number1-2
Early online date25 Apr 2018
DOIs
Publication statusPublished - Jul 2018

Keywords

  • Crop model
  • Crop yield
  • Root growth model
  • Soil compaction
  • Soil strength

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