Sugarcane root growth modelling by coupling soil structure to physical stresses

• Grant number: 25/06634-9
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: July 01, 2025
• End date: October 31, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Moacir Tuzzin de Moraes
• Grantee: Mariane Dias Macedo
• Supervisor: Andrea Schnepf
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: Forschungszentrum Jülich, Germany
• Associated to the scholarship: 24/15892-9 - Soil structure contribution to mitigation of the physical stress to sugarcane root elongation, BP.IC

Abstract

The root system growth is essential for crops establishment and development. Usually, the root elongation rate is negatively affected by soil physical stresses, mainly mechanical and water stresses. The data impacts of soil physical stresses are scarce for sugarcane root elongation rate. Under these conditions, the soil structure, especially the presence of biopores, can contribute to mitigating the total physical stresses on root elongation. The objective of this study is modelling the sugarcane root growth as a function of soil mechanical and water stresses, as well as the contribution of soil structure for root growth. The project was based on a long-term (since 1993) field experiment with sugarcane (Saccharum officinarum) cultivation in a succession system with soybean (Glycine max L.) in a Oxisol with a very clayey texture. The experimental area is located at the Sugarcane Research Center of the Agronomic Institute of Campinas, in Ribeirão Preto, São Paulo state. Total physical stress models on root elongation were created for three soil physical-structural conditions, corresponding to (i) conventional cultivation system, (ii) conservation cultivation system with no-tillage, both with undisturbed soil structure, and (iii) packed soil samples with reconstructed structure. Samples with preserved and unpreserved soil structure were collected at 0-20 cm depth in the corresponding field plots. Soil physical stresses were determined, for each treatment, by means of 5 mechanical stress levels (soil compaction degrees), 5 water stress levels (soil water matric potential of -5, -60, -1000, -5000 and -8000 hPa) and 4 replicates. The models will be compared based on the root elongation rate of sugarcane as a function of physical stress levels. Sugarcane root growth will be simulated using the CRootBox model in Python, considering different root types and specific parameters. The simulation will cover 365 days and will be fitted with data on root distributions under field conditions, as found in the literature.