Use of Pedotransfer Equations (PTF) to Estimate soil Density in the Hydrographic Basins of The Amambai, Iguatemi and Ivinhema Rivers in the State of Mato Grosso do Sul

Abstract

Theoretical framework: Bulk density (Bd) is a physical property of soil used as an indicator of soil compaction, influencing root growth and density, water movement and retention in the soil, it is an essential characteristic for assessments of carbon stocks or other nutrients in the soil.   Objective: This studyevaluates the accuracy and selects pedotransfer functions (PTFs) for Bd estimates for soils in the Amambai, Iguatemi, and Ivinhema River basins in Mato Grosso do Sul - MS.   Method: Estimates of Bd values of the samples were made using eleven PTFs-Bd that were calibrated to estimate Bd for Brazilian soils. The accuracy of PTFs-Bd predictions is evaluated based on the lowers root mean square error (RMSE) and the highers coefficient of determination (R²).   Results and conclusion: Among the eleven analyzed PTFs-Bd, the most accurate ones were PTFs- Ds 1, 2, 3, and 4 by Huf dos Reis et al. (2024) and the one by Tomasella and Hodnett (1998). PTF-Bd 3, which uses fine and coarse sand and clay as predictors, showed the highest accuracy for the total dataset (88 samples). PTF-Bd 5 obtained better accuracy in estimating Bd in Latossolos Vermelhos, Argissolos Vermelho Amerelos, and Neossolos Quartzarênicos.   Research implications: Identifying the best PTFs for estimating Bd for the study area's soils will facilitate other research as carbon stocks estimation and use of hydrophysical PTFs that use Bd as predictor.   Originality/Value: PTFs for estimating Bd for soils in the state of MS have not yet been developed, highlighting the need to evaluate and indicate between existing PTFs the more accurate.