Physics-Informed Neural Networks for Soil Water Retention Curves R package soilFlux version 0.1.5 Implements a physics-informed one-dimensional convolutional neural network (CNN1D-PINN) for estimating the complete soil water retention curve (SWRC) as a continuous function of matric potential, from soil texture, organic carbon, bulk density, and depth. The network architecture ensures strict monotonic decrease of volumetric water content with increasing suction by construction, through cumulative integration of non-negative slope outputs (monotone integral architecture). Four physics-based residual constraints adapted from Norouzi et al. (2025) <doi:10.1029/2024WR038149> are embedded in the loss function: (S1) linearity at the dry end (pF in [5, 7.6]); (S2) non-negativity at pF = 6.2; (S3) non-positivity at pF = 7.6; and (S4) a near-zero derivative in the saturated plateau region (pF in [-2, -0.3]). Includes tools for data preparation, model training, dense prediction, performance metrics, texture classification, and publication-quality visualisation. Software Depends: R (>= 4.1.0) Imports: dplyr (>= 1.1.0), tidyr (>= 1.3.0), ggplot2 (>= 3.4.0), purrr (>= 1.0.0), tibble (>= 3.2.0), stringr (>= 1.5.0), reticulate (>= 1.34.0), tensorflow (>= 2.14.0), rlang (>= 1.1.0) Suggests: keras3 (>= 1.0.0), ggtern, readxl (>= 1.4.0), scales (>= 1.2.0), knitr, rmarkdown, testthat (>= 3.0.0), withr Hugo Rodrigues <rodrigues.machado.hugo@gmail.com> Comprehensive R Archive Network (CRAN) Hugo Rodrigues [aut, cre] (ORCID: <https://orcid.org/0000-0002-8070-8126>) MIT + file LICENSE (https://CRAN.R-project.org/package=soilFlux/LICENSE) 2026-03-26 application/tgz https://CRAN.R-project.org/package=soilFlux doi:10.32614/CRAN.package.soilFlux