How to track growing degree-days, precipitation and growth stages
Reading time: 10 min
Check the amount of heat and precipitation your fields receive, evaluate the change of these indicators, leave notes and mark data about your crop development in free OneSoil web platform for precision farming
Growing degree-days
For growth and development, the plant needs heat. To enter the new stage of the development, or phenophase, every plant requires a specific amount of heat. Growing degree-day (GDD) is a measure of heat the plant has accumulated to date.
For instance, in Belarus, for alfalfa to bloom it needs 400–475 degree-days, and for spring wheat to emerge 67 degree-days are needed. During colder-than-usual years, the plant will need more time to accumulate the required amount of growing degree-days; during warmer-than-usual years – less time.
For instance, in Belarus, for alfalfa to bloom it needs 400–475 degree-days, and for spring wheat to emerge 67 degree-days are needed. During colder-than-usual years, the plant will need more time to accumulate the required amount of growing degree-days; during warmer-than-usual years – less time.
Philip Kondratenko
Agronomist
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Philip Kondratenko
Agronomist
For growth and development, the plant needs heat. To enter the new stage of the development, or phenophase, every plant requires a specific amount of heat. Growing degree-day (GDD) is a measure of heat the plant has accumulated to date.
For instance, in Belarus, for alfalfa to bloom it needs 400-475 degree-days, and for spring wheat to emerge 67 degree-days are needed. During colder-than-usual years, the plant will need more time to accumulate the required amount of growing degree-days; during warmer-than-usual years – less time.
For instance, in Belarus, for alfalfa to bloom it needs 400-475 degree-days, and for spring wheat to emerge 67 degree-days are needed. During colder-than-usual years, the plant will need more time to accumulate the required amount of growing degree-days; during warmer-than-usual years – less time.
We build a chart from the sowing date which OneSoil web-platform users have to record themselves.
We use the following formula:
1) Add each day's maximum and minimum temperature;
2) Divide the sum by two to get the average temperature;
3) Subtract the base temperature for the plant.
The base temperature is the minimum threshold below which the plant development stops. For instance, for wheat it is +5 С° – only above this temperature does the vegetation begin. For different crops in different countries, base temperatures may vary.
We use the following formula:
1) Add each day's maximum and minimum temperature;
2) Divide the sum by two to get the average temperature;
3) Subtract the base temperature for the plant.
The base temperature is the minimum threshold below which the plant development stops. For instance, for wheat it is +5 С° – only above this temperature does the vegetation begin. For different crops in different countries, base temperatures may vary.
The chart of accumulated precipitation
For building the charts, we once again use weather data from NOAA and DarkSky. The charts of accumulated precipitation allow us to evaluate the soil's moisture reserve. Using this information, you can predict the yield and calculate fertilizer rates more accurately.
The chart of vegetation change
There is also a chart that shows the change of the NDVI index for each day (if there was a clear satellite image). The purple line stands for the average value of the NDVI for a field. The upper and the lower points of the light-purple range indicate the maximum and the minimum NDVI values for the day. If you want to see the visual representation of the NDVI index, simply choose the day and click on the chart. In a separate browser window, the field photo with the NDVI visualization will open.
Notes and growth stages
Growing degree-days allow us to predict plant phenophases. This info is crucial for planning field works such as fertilizer and pesticide application, as well as harvesting. Using our GDD chart, you can easily add notes and track growth stages, which is really cool.
How to use notes:
How to use notes:
1
Save all the info in one place. The crop, the season, sowing date, harvest date, precipitation, growing degree-days, weather forecast, field operations, phenophases – you can keep all the records on plant development in one place. This data will never be washed away with the rain or eaten by your dog (as it so often happens to paper notes).
2
Analyze the weather impact on crops. You can analyze how the weather affected plant development. When determining the required amount of degree-days for a crop, we usually rely on books and research. Keeping your own records will allow you to rely on your own experience.
3
Predict growth stages. If you have data on phenophases for several years, you can better understand when a particular stage will begin. When using our charts, you can easily switch between years.
The BBCH scale has several important advantages over other similar scales. First, it is very detailed – for the main crops, the scale describes 70-100 stages of development. Secondly, it is international – there are official translations in English, French and Spanish languages. It is also used by large producers of seeds, fertilizers and pesticides in their product descriptions; thus helping to spread the BBCH scale in the world.
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