By John Heard Field Crop Nutrition Specialist MAFRD
May 28, 2015 - With the excessive rainfall and standing water in some Manitoba fields, some agronomists may be asked to assess possible nitrogen (N) losses. If applied N had already converted to nitrate (NO3-) form, it is subject to leaching on sandy soils and denitrification on poorly drained and heavier textured soils.
In many cases, it is not too late to apply your "Nitrogen Rich Strip" or N Stamp" that can serve as a reference when one wants to assess potential losses and yield penalties. Nitrogen Rich Strips are usually applied with field equipment and run across the field to encompass a range of soil types, drainage, etc. Simple differences in colour and growth between the field and this strip usually indicate a lack of N for field yield potential. When applied before or at seeding, such strips should be 150-200 per cent of the base field N rate. A number of devices and sensors (like chlorophyll sensors, NDVI or GreenSeeker) can be used to quantify such a difference and estimate in-season N applications for a variety of crops.
Read more about Nitrogen Ramp Calibration Strips or N Stamps.