Soil structure contribution to mitigation of the physical stress to sugarcane root elongation

• Grant number: 24/15892-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Moacir Tuzzin de Moraes
• Grantee: Mariane Dias Macedo
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated scholarship(s): 25/06634-9 - Sugarcane root growth modelling by coupling soil structure to physical stresses, BE.EP.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 impacts of soil physical stresses are scare 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 to parameterize the root elongation rate of sugarcane as a function of soil mechanical and water stresses, as well as the contribution of soil structure for root growth. The project will be based on a long-term (since 1998) 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 will be 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 will be collected at a depth of 0-20 cm in the corresponding field plots. Soil physical stresses will be determined, for each treatment, by means of 5 levels of mechanical stress (degrees of compaction), 5 levels of water stress (soil water matric potential of -5, -60, -100, -1000 and -5000 hPa) and 4 replicates. The models will be compared based on the root elongation rate of sugarcane as a function of physical stress levels. It is expected that (i) the root elongation rate will be negatively affected by the increase in soil resistance to penetration, as well as by water deficit and hypoxia/anoxia in the soil; and (ii) the soil structure, especially the presence of biopores, will contribute to the mitigation of total physical stresses to root system growth.