Characterization of drought stress in the macaúba palm

• Grant number: 24/19366-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2025
• End date: February 28, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Quirijn de Jong van Lier
• Grantee: Gustavo Marques Vianna Querino
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The macaúba is a palm tree with high productive potential, surpassing crops like soybeans and oil palm. Its adaptability to various Brazilian biomes, especially the cerrado, and the possibility of cultivation in degraded areas make it a relevant crop for environmental recovery and the sustainable production of biofuels. However, one of the requirements to fully explore its potential is understanding the plant's response to drought stress due to a lack of water, which is linked to the process of root water uptake (RWU). To contribute to this understanding, the present study aims to calibrate the Feddes reduction function (FRF) and MFlux for the macaúba crop. This calibration will be based on the observation of drought stress in rainfed plants, comparing them with irrigated plants under the edaphoclimatic conditions of Piracicaba, SP. The methodology is divided into three stages. First, a field experiment will be carried out to assess the initial development of the macaúba root system and characterize the soil's hydraulic properties. Next, the matric potentials and critical water content will be identified, using the Feddes and MFlux models to determine drought stress limits. Finally, the hydrological model SWAP will be used to simulate the crop's fitness under drought stress in different locations in Brazil, based on data from the literature. The results are expected to contribute to a better understanding of the macaúba's water behavior and the development of efficient management strategies. As a result, it is expected to identify the critical soil moisture levels at which root water uptake is reduced, calibrate the transpiration parameters (Feddes h3 and Mlim), establish specific parameters for future studies and simulations, and perform simulations of the macaúba's water dynamics using the SWAP model. Thus, the project should contribute to modeling the productivity of macaúba and, consequently, to more efficient and sustainable agricultural practices in regions facing water scarcity.