At Yara, we've gained years of experience and expertise through field trials and know that every Variable N-Rate Application optimises nitrogen use efficiency and improves both yield quality and protein content. That's why we recommend Variable N-Rate Application for every fertiliser application.

Fertiliser applications

First and second application

Variable rate fertilisation improves the homogeneity of your crops and fields in the early growth stages by not applying nitrogen to areas with high biomass but where the crop is underdeveloped. This is particularly important for promoting tillering and stem elongation.

The Atfarm levelling strategy is best used for the first and second applications. Read here about the variable rate strategies.

For the first application we've found that nitrogen isn't always the reason for differences in crop growth. Please decide based on your own experience and the field conditions when to apply variable rates.

Third application

Variable N-Rate Application maps show you where to apply how much nitrogen. This allows you to increase protein levels in high biomass areas and reduce nutrient losses in low biomass areas.

If this is your last application, use the protein dressing strategy in Atfarm, but if you're planning another application, use the levelling strategy. Read here about the variable rate strategies.

Fourth application

If you opt for a fourth application, you can use variable rate fertilisation to increase protein levels by applying nitrogen only to areas of high biomass, thus counteracting protein dilution in high yielding crops.

The Atfarm protein dressing strategy is best used for the fourth application. Read here about the variable rate strategies.

Growth stages

Depending on the crop type, and therefore whether the VRA N-Sensor algorithm is used, the growth stage can be selected when creating application maps. The VRA N-Sensor algorithm is based on thousands of samples and lab tests and adapts to the crop and growth stage.

Atfarm recommends a range of growth stages to select from depending on the crop type. If Variable Rate Application (VRA) isn't agronomically feasible for a particular growth stage, that growth stage can't be selected.

These BBCH stages can be selected for crops in Ireland: