Integrated indicators of soil physical-hydric and carbon sustainability in intercropped systems under long-term no-tillage

• Grant number: 25/10409-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2025
• End date: September 30, 2028
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Carlos Alexandre Costa Crusciol
• Grantee: Marcela Pacola Oliveira
• Host Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated research grant: 21/10573-4 - Center for Carbon Research in Tropical Agriculture (CCARBON), AP.CEPID

Abstract

The sustainability of tropical agricultural systems depends on conservation practices that preserve soil structure, optimize water use, and increase organic matter. This project aims to integratively assess the effects of intercropping systems under long-term no-tillage on soil hydro-physical quality. The study will be conducted in an experiment initiated in 2006 at the Lageado Experimental Farm (UNESP, Botucatu-SP), part of the Global Long-Term Agricultural Experiment Network (GLTEN). Four systems based on soybean in the summer and second-crop maize will be compared: sole cropping and three intercropping systems with Urochloa ruziziensis, Crotalaria spectabilis, and a combination of both species. Analyses will address the Least Limiting Water Range (LLWR), physical fractionation of soil organic matter (SOM), root growth, carbon stocks, and water storage capacity. Soil physical attributes (bulk density, porosity, penetration resistance) and grain yield will also be evaluated. The hypothesis is that plant diversification via intercropping with cover crops improves soil hydro-physical quality by expanding the LLWR, stabilizing moisture, and promoting greater carbon accumulation in stable SOM fractions. Integrating physical, hydrological, and biochemical indicators will enable a robust diagnosis of soil quality. The project's originality lies in the combined application of SOM fractionation methods, water retention curves, and LLWR modeling in tropical intercropping systems, addressing gaps in understanding soil resilience under agricultural management and climate change. The results will support sustainable agricultural practices, especially in regions with seasonally dry climates.