Q: Can field performance be enhanced by a better understanding of the soil and nutrition placement?
A: Soil nutrition in a field can be looked at like a blanket — not the boring, white, duvet-type of blanket, but a more unique quilt with diversity in patterns and colours. This soil variability in the field changes nutrition needs and where they are best placed and utilized in the field. Hilly landscapes are the most obvious but often the flattest landscapes are as variable, just less so to the naked eye. To best manage soil and nutrition long term, we must investigate and identify the variability.
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One of the simplest methods is to run NDVI (Normalized Difference Vegetative Index) to look historically at the low, average and high vegetative areas. Once these areas are visual, it is easy to complete comparative soil tests in each of the areas looking at nutrient and salinity levels as well as soil texture.
Understanding the lower- producing areas can give guidance to place more or less nutrition in these areas based on the limiting factor(s). Is it soil texture and a sand ridge? Is it a saline area? Lacking a specific nutrient? Once this is understood, soil nutrition in a field can start to be managed in finer detail.
Use of variable-rate fertilization is the easiest way to do this. With sensing technology and satellite imagery, a base rate of nutrition can be adjusted to the areas of variability noted by NDVI and other scientific calculations.
Understanding the why provides the ground truth in nutrient placement. If each acre in the field does not have the same potential, why treat it that way? Increasing fertility rates in the areas of high potential matches best the uptake and removal.
By understanding variability across the landscape, we can make better decisions for where fertility is best placed to maximize crop potential. We can better understand the soil by using NDVI imagery along with soil testing to better place fertility with the use of variable-rate technology and nutrient placement.
Brianna Lummerding, B.Sc., PAg, CCA, is a manager of agronomic services for Nutrien Ag Solutions in north-central Saskatchewan.
