Agronomy
Ag Fundamentals
Nitrogen Loss & MRB Depth Setting
3 Years of Replicated Trials
Nitrogen loss and MRB Depth Setting
Figure 1
Combined Results from 2015, 2016, and 2017 Trial Years
Fertilizer loss due to volatilization (gassing off) robs farmers of potential profit, which wastes resources and can have a negative effect on the environment.
Bourgault recommends setting your MRBs® between 2"-3" below the original soil surface in order to access soil moisture and to ensure adequate soil coverage to prevent gassing off. This is based off of 3 years of replicated trials.
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Figure 2
Urea Pathway from Urea to Nitrate (plant available nitrogen)
The greatest risk of loss in the urea pathway is after urea converts into ammonia (NH3) and before being converted into ammonium (NH4). The complete pathway is seen in figure 2.
Testing conducted by the Bourgault Agronomy Team observed differences in nitrogen loss and crop yield when comparing urea banded at 1", 2" and 3” depths, in multiple years and moisture conditions. Depth of band was measured from the original ground level to the depth of the urea. The measurement does not include the soil that is thrown over the band by the openers.
Dosimeters, figure 3, were used to determine if there was any free ammonia lost into the atmosphere. The treatments were then brought to yield.
Figure 3
Dosimeter and relative size
Results from Individual Years
The results differed between years due to the spring seeding conditions:
Figure 6
2017 Results in adequate moisture spring. Nitrogen depth was important to reduce loss
Figure 5
2016 Results in a Wet Spring. Nitrogen depth was not as critical to reduce loss
Figure 4
2015 Results in a Dry Spring. Nitrogen needed to be deeper to reduce loss
The required depth of the nitrogen band will depend on the conditions at the time of seeding. It is important to get the nitrogen band into moisture to reduce loss. Some years this depth will be deeper than other years dependent on where the soil moisture is. Setting the depth too deep will create more drag, which will potentially increase fuel consumption and equipment wear.