November 2017

BLUE-THUMB-UP: a free webtool to help farmers improve their water use, yields and sustainability.

Using BTU to predict irrigation requirements for crops

BLUE-THUMB-UP is an Online free web tool that provides easy access to information to improve productivity and sustainability of water use in farms at any location in the world.



The tool provides you with information on the water needs of your crop in the next four days and an estimate of water availability in the soil. Soil moisture is estimated by you and the amount of rain predicted. The tool assesses if the water in the soil is enough for your crop. If it is not, it tells you so and gives estimation of the amount of irrigation water you need to apply.

We have developed BLUE-THUMB-UP to show that global data, models and field level information can be combined in a web-platform to provide advice to farmers on the water needs of their crops and if irrigation is required.

The tool is free so that everybody in the world may access to it and use it for their own benefit. Please use it, share your experiences with us and give us yours suggestion for additional features.

BLUE-THUMB-UP is developed by Good Stuff International B.V. as part of its WaterData4Action approach. Other WaterData4Action tools are:




Brief technical documentation for Blue Thumb Up:

BLUE-THUMB_UP calculates a daily soil water balance to assess if your crop needs additional water. The irrigation requirement (IRR) is estimated by summing the soil water content (SWC) and the effective rain (Peff, assumed to be 75% of total rainfall predicted following FAO, 1986) and substracting that from the evapotranspiration (ETc) by your crop (IRR = ETc-SWC-Peff). Once IRR becomes positive, your crop requires irrigation water.

The evapotranspiration of your crop (ETc) is calculated by multiplying the reference evapotranspiration with an average crop specific coefficient (Kc, average derived from FAO,1998). The reference evapotranspiration is calculated on using the local weatherdata and the Penman-Monteith equation. The soil water content (SWC in mm water / m soil) is estimated on user inputs on the texture of your soil and the estimated wetness of the soil in five classes (%) ranging from dry (5% of SWC) to really wet (100% of SWC). Soil water availability to the crop (mm) is calculated by multiplying the root depth (in m). If the soil water availability (mm) is lower then the evapotranspiration by the crop (mm), the irrigation requirement is calculated as the difference between soil moisture and Etc.

The BLUE-THUMB-UP website only uses open source data, software and models. The weather data used are obtained from OpenWeatherMap. Sofware and code used are: DJANGO and PYTHON, Chart.js and Leaflet Javascript as well as bootstrap HTML, CSS, JS framework. We say thanks to all that have contributed!

DISCLAIMER: The information and guidance provided by the BLUE-THUMB-UP webapp is provided free of charge and are estimates based on open source weather data, the Penman-Monteith equation to estimate reference evapotranspiration and best guess soil water content estimates based on user inputs and rainfall. BLUE-THUMB-UP uses average crop coefficients in the calculations. Good Stuff International B.V. is never liable for any claim associated with the information provided by the BLUE-THUMB-UP WebApp. All responsibility for using BLUE-THUMB-UP rests with the user.