Important information NCALC

The aim of the "In season nitrogen calculator" is to calculate and then apply the exact amount of N required to maximize the yield potential of the paddock where N is a limiting factor.
The system is based around "ASKING THE PLANT" if it is responding to extra N.
This is done by making a direct comparison between an N rich strip and the farmer practice.
The calculator is calibrated to use the NDVI readings from a greenseeker.
The calculations will target grain protein levels of 10.5% in wheat and barley.
11.5% or 12.5% protein in wheat can be achieved by using rates indicated.

Inputs required

• Crop type
• Accurate seeding date. If crop was dry sown then use date of germinating rain.
• Sensing date
• NDVI from N strip
• NDVI from farmer practice

When to use the N Calculator

• Before any in-season application of N
• In barley before 55 days from planting (recommended)
• In wheat from 20 to 70 days from planting
• In Canola when NDVI is between .5 and .7

Useful tips

• Apply N rich strips early (PSPE) at a rate of 100 units/ha across all management zones.
• Strips need to be laid across the workings or at worst 45deg to remove the distortion of header trails or wheel tracks.
• Take farmer practice reading from as close to the N rich strip reading as possible
• Apply in season calculated rate of N in accordance with local "best practice" to avoid crop damage and/or losses to the environment.
• Heavy leaching rains on light soils after application may distort outcomes.

When not to use the N calculator

• After a crop has been grazed
• If the crop has suffered from waterlogging

Testing the system
A protein test on the grain at harvest from the zone is all that is required to truth your N management.