What is photo analysis? Which crops can it be used on and when should it be used?

With photo analysis in the YaraPlus mobile app, you can estimate crop nitrogen needs by taking a few photos. 

The app detects leaf cover in your images and uses this information to estimate N-uptake and, in the case of winter oilseed rape, the fresh matter weight. These calculations are based on field trial data, providing a nitrogen recommendation tailored to your crop and region. You don't need to set up fields first – you can assign a result to a field later.

As all recommendations are based on a nutrient element, photo analysis can also be used in organic farming.

Crops, timing and results

In Germany, photo analysis is used for winter wheat and winter oilseed rape. Only use it in early growth stages when the soil is still visible when looking straight down. The accuracy of the analysis decreases once the canopy closes.

For applications in cereals at BBCH stage 31 onwards, use the Yara N-Tester.

Crop	When to measure	Result you'll see	What it means
Winter oilseed rape	Autumn: just before winter dormancy sets in when growth has ceased (height 5-60 cm, row spacing ≤50 cm) Spring: optional follow-up to assess winter losses Limit: leaf cover ≤80 % (≤80 kg N/ha)*	N-recommendation (kg N/ha)	Total N for the season, can be split into two applications (e.g., BBCH 20-27 and BBCH 30-39)
		N-uptake (kg N/ha)	Used to evaluate the growth and nitrogen uptake of the crop
		Fresh matter weight (t/ha)	Estimated from crop height and leaf cover to help calculate nitrogen needs
Winter wheat	Spring: BBCH 20-30, row spacing 12-30 cm Limit: leaf cover ≤70 % (≤40 kg N/ha)*	N-recommendation (kg N/ha)	Suggested rate for the first N application (tillering)
		Leaf cover (%)	Used to evaluate the crop density of the field

*The app blocks images above these thresholds to avoid misleading results

What to do with the recommendations

Use your results to:

• Create variable-rate application maps
• Plan fertilisation for the season
• Browse the Yara fertiliser catalogue

Learn more

How to use photo analysis

How the recommendations are calculated