MAPPING BRAZILIAN SOIL LIMESTONE LEVELS: IMPACTS ON AGRICULTURE

• Grant number: 24/20787-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: José Alexandre Melo Demattê
• Grantee: Miguel Palacio Pelaez Carvalho Neto
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Soil pH is one of the most important property since regulates plants absorption. Specifically in Brazil, it is a significant constraint to crop yields, making necessary lime application to improve soil fertility. This project aims to develop detailed lime requirement maps for Brazil, indicating the necessary lime quantities for soil layers up to 100 cm deep. We hypothesize that machine learning maps of the soil-key parameters can combine to predict lime requirements with accuracy comparable to traditional empirical methods. This approach promises rapid, precise, and cost-effective solutions to Brazil's agricultural challenges, providing valuable insights for decision-makers. The project will generate maps of key soil parameters-Calcium (Ca2+), Magnesium (Mg2+), Potassium (K+), Hydrogen (H+), Aluminum (Al3+), and pH-using Random Forest (RF) model in a Google Earth Engine and Google Collab environment. These parameter maps will be utilized in empirical lime requirement (LR) formulas through map algebra to create spatially explicit LR maps. Model performance will be evaluated through 10-fold cross-validation, using the metrics coefficient of determination (R2), root mean square error (RMSE), and the Ratio of Performance to Inter Quartile distance (RPIQ). This type of work is under the FAO vision where "we cannot manage if we do not know it". Expected results include accurate and detailed lime requirement maps that will enhance soil management practices across Brazil, addressing soil fertility issues effectively and supporting agricultural efficiency on a national scale.