OSR GAI Online

Step 1 - Take a digital photograph

Take a digital photograph of the crop which is representative of the field and save this to your PC.

Step 2 - Upload your photograph

Browse and submit the photograph using the upload facility below, being sure to choose type of calculation required; assessment of 'Nitrogen Content' (from GAI) or 'Lodging Risk'.

Note: To gain the most accurate results from the tool, digital photographs should be taken directly above the crop. The area of crop photographed is not critical and a 1m x 1m is perfectly adequate. It is advisable to avoid taking photographs on sunny days as this may cause shadows. Note: An image taken using a camera phone is perfectly adequate. Taking at least 3 photographs per field and averaging the GAI is also advised to get the most accurate GAI reading.

Step 3 - Wait for your results to be calculated

The GAI tool will show 2 images; your original photograph and a processed black and green image to check that the tool is correctly identifying the green crop. If the tool is not correctly identifying the green crop, then it is recommended that another photo is taken a few days later in different light conditions.

Use this app to measure the GAI just before stem extension in late February.

GAI > 0.8 Caryx® 0.7 - 1.0 l/ha (Higher rate where tall variety / fertile site)

GAI > 2.0 Caryx® 1.0 - 1.4 l/ha (Higher rate where tall variety / fertile site)

If LLS is active, add tebuconazole 0.5 l/ha or prothioconazole 0.3 l/ha. Tebuconazole will have neglible PGR activity.


  • From start of stem extension to yellow bud
  • When spring growth has started, although a few cold nights won't matter

Why Caryx®?

Caryx® is the only OSR product to have achieved registration solely on its PGR ability and is a key OSR management tool.

Reduces lodging and creates open canopy+0.4 t/ha if lodging occurs
Reduces height and lodging risk. ADAS aerial surveys show that 31% of crop lodges each year.
Creates an open canopy+0.2 t/ha where no lodging
Reduces apical dominance and allows more light into the canopy. 15 dose response trials showed a yield benefit of 0.21 t/ha of Caryx® at 1.0 l/ha vs untreated.
Improves rooting+0.2 t/ha in a dry year
Caryx® increases rooting at depth by 35%, protecting yield in a dry summer (this occurs every 2-3 years)
Dual ai activityMepiquat chloride & metconazole
Copes with variable spring temperatures and across a wide growth stages range

Caryx® is a registered trademark of BASF. Caryx® contains mepiquat chloride and metconazole. Use plant protection products safely. Always read the label and product information before use.

This tool is compatible with JPEG (.jpeg, .jpg) images.

If checking GAI for fertiliser application, don't forget to check again for your Sunorg Pro® needs.

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The first oilseed rape product to justify its label approval on the strength of its growth regulation capabilities alone, Caryx® reduces lodging risk, creates a more open canopy and increases rooting at depth, minimising risks and optimising yields.

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Sunorg® Pro

Sunorg® Pro is a broad spectrum fungicide with curative and protectant activity, which can be used on all commercial varieties of winter and spring wheat, durum wheat, winter and spring barley, rye and triticale. Sunorg® Pro can also be used on oilseed rape, field beans, combining and vining peas and lupins.

When applied to oilseed rape in the spring, Sunorg® Pro can provide plant growth regulation in the form of a reduction in crop height.

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