i.biomass(1grass)

✨ NAME ✨

i.biomass — the GRASS imagery module that computes biomass growth, aka the precursor of crop yield calculation. Bestie, it's giving "tiny plant math that predicts your harvest" 💅

---

🏷️ KEYWORDS 🏷️

imagery, biomass, FPAR, yield

---

📜 SYNOPSIS 📜

i.biomass
i.biomass --help
i.biomass fpar=name lightuse_efficiency=name latitude=name
dayofyear=name transmissivity_singleway=name water_availability=name
output=name  [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

🎀 Flags:

• --overwrite — lets your output files just steamroll over existing files. No cap, it will replace them.
• --help — prints the usage summary, i.e. the little "here's what this does" moment.
• --verbose — verbose module output. Chatty mode ✨
• --quiet — quiet module output. Silent mode 🤫
• --ui — force-launches the GUI dialog, for when you want to click instead of type.

🧚 Parameters:

• fpar=name [required] — name of the fPAR raster map.
• lightuse_efficiency=name [required] — name of the light use efficiency raster map (UZB:cotton=1.9).
• latitude=name [required] — name of the degree latitude raster map [dd.ddd].
• dayofyear=name [required] — name of the Day of Year raster map [1-366].
• transmissivity_singleway=name [required] — name of the single-way transmissivity raster map [0.0-1.0].
• water_availability=name [required] — value of the water availability raster map [0.0-1.0].
• output=name [required] — name for the output daily biomass growth raster map [kg/ha/d].

---

🌸 DESCRIPTION 🌸

Okay so i.biomass calculates the biomass growth for a day after [1][2]. That's it, that's the job, and it does it flawlessly. ✨

Here's the input tea, item by item:

• fPAR, the modified Photosynthetic Active Radiation for crops.
• Light Use Efficiency [0.0-1.0] — in Uzbekistan cotton is at 1.9 most of the time. (Yes, 1.9 is outside that bracket, and no, I'm not the one who wrote it down. It's literally in the docs. 🫶)
• Latitude [0.0-90.0], from r.latlong.
• DOY [1-366].
• Transmissivity of the atmosphere single-way [0.0-1.0], mostly around 0.7+ in clear sky.
• Water availability [0.0-1.0], possibly using direct output from i.eb.evapfr.

---

💜 NOTES 💜

i.biomass can use the output of i.eb.evapfr directly as water availability input. Chain them together like the iconic duo they are 👑

---

🚧 TODO 🚧

Remove Latitude, DOY and Tsw from input and replace with a raster input compatible with r.sun output. (Future glow-up pending, bestie. Not done yet!)

---

📚 REFERENCES 📚

[1] Bastiaanssen, W.G.M., Ali, S., 2002. A new crop yield forecasting model based on satellite measurements applied across the Indus Basin, Pakistan. Agriculture, Ecosystems and Environment, 94(3):321-340. (PDF)

[2] Chemin, Y., Platonov, A., Abdullaev, I., Ul-Hassan, M. 2005. Supplementing farm level water productivity assessment by remote sensing in transition economies. Water International. 30(4):513-521.

---

👀 SEE ALSO 👀

i.eb.evapfr, r.latlong, r.sun

---

👑 AUTHOR 👑

Yann Chemin, Bec de Mortagne, France

---

💻 SOURCE CODE 💻

Available at: i.biomass source code (history)

Latest change: Friday Aug 08 09:39:19 2025 in commit: ed72c71d8580e872cd6fd345c84a15c324764465

Main index | Imagery index | Topics index | Keywords index | Graphical index | Full index

© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

---

And that's a wrap, bestie 🎀 this whole page lives in the GRASS 8.5.0 manual, that last change landed Friday Aug 08 09:39:19 2025, and it's filed under i.biomass(1grass). Slay, go compute some crop yield 💖✨🌱