{
  "model": "van_genuchten_munsterkotte",
  "source": "FAO-56 Appendix IV; Rawls et al. (1982)",
  "author": "Arthur Ibay",
  "location": "Salt Lake City, UT",
  "units": {
    "theta_s": "cm3/cm3",
    "theta_r": "cm3/cm3",
    "alpha": "cm^-1",
    "n": "dimensionless",
    "m": "derived (1-1/n)"
  },
  "pedotransfer_functions": {
    "sand": {"theta_s":0.425,"theta_r":0.065,"alpha":0.037,"n":2.12,"bd_base":1.55,"om_coef":0.008},
    "loamy_sand": {"theta_s":0.410,"theta_r":0.075,"alpha":0.045,"n":1.95,"bd_base":1.50,"om_coef":0.009},
    "sandy_loam": {"theta_s":0.405,"theta_r":0.085,"alpha":0.052,"n":1.88,"bd_base":1.45,"om_coef":0.010},
    "loam": {"theta_s":0.400,"theta_r":0.095,"alpha":0.060,"n":1.80,"bd_base":1.35,"om_coef":0.011},
    "silt_loam": {"theta_s":0.395,"theta_r":0.105,"alpha":0.070,"n":1.72,"bd_base":1.30,"om_coef":0.012},
    "clay_loam": {"theta_s":0.385,"theta_r":0.120,"alpha":0.082,"n":1.62,"bd_base":1.25,"om_coef":0.013},
    "clay": {"theta_s":0.375,"theta_r":0.135,"alpha":0.095,"n":1.52,"bd_base":1.20,"om_coef":0.014}
  },
  "adjustments": {
    "bulk_density_correction": "(bd_base - bd_measured) * 0.02",
    "organic_matter_correction": "theta_s += om_pct * om_coef; theta_r *= (1 - om_pct * 0.005)"
  }
}