About a decade ago, Variable Rate Technology (VRT) was relatively new, and its adoption among farmers was gaining momentum, albeit at a slower pace compared to today. Modern agriculture now offers various ways to implement VRT based on different layers of information about your crops, fields, and soils. Two of the most commonly used and valuable methods are EC soil scanning and NDVI imagery. Both are readily available on the market, but how do you choose the most suitable one for your farm’s specific needs and conditions?
As a team of senior agronomists with extensive experience in VRT technology across different provinces in Canada, we understand how to utilize both EC scanners and NDVI imagery based on your farm’s requirements.
Pros and Cons of Each Approach
In most cases, NDVI multiyear imagery provides extremely accurate VR maps that reflect areas with high and low production potential, which we can manage separately. However, there are fields with more complex characteristics where EC topsoil scanning provides additional clarity regarding soil properties like EC, texture, compaction, and others. Topsoil EC scanning should ideally be done once in a lifetime to create a comprehensive snapshot of the soil profile. Unless any major field alterations are done (drainage, clearing, etc.)
EC soil scanning machines are sophisticated tools designed to measure the electrical conductivity of soil, providing insights into its texture, moisture content, and salinity levels at various depths. While soil scanning is more time-consuming and costly, we usually start with scanning a few fields initially. If a farmer decides to extend the number of scanned fields, we adjust the scanning plan accordingly.
On the other hand, creating NDVI-based maps involves using imagery from multiple years during the vegetation season. Modern EC scanners are quite versatile and can work effectively on bare soil, with or without residue, in rainy conditions, or even through a snow cover.
Choosing the Right Approach
VRT based on EC soil scanning and VRT based on NDVI imagery each have their strengths, and by understanding them, we can decide which one is best suited to your specific situation. We implement a field-specific approach to ensure accuracy and effectiveness.
Common Benefits of Each Technology
1. VRT based on EC Soil Scanning:
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Effective in fields with significant soil variability, such as salinity levels, texture, and moisture content.
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Provides direct measurements of soil properties, enabling informed decisions about input application rates.
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2. VRT based on NDVI Imagery:
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- Creates yield potential maps based on crop vigor and biomass accumulation, identifying areas of stress or nutrient deficiency.
- Helps delineate crop management zones based on vegetation characteristics.
- Provides a broader perspective on crop performance and health that complements soil-based approaches.
Additionally, we can adapt the maps by combining the most impactful limiting factors on each specific field. For instance, if compaction affects yield in certain areas, we can add it as an additional factor to the map to reflect field variability accurately. Other factors considered include yield maps, slope, water accumulation, topography maps, etc.
Despite the source of the VRT map, the soil sampling process remains the same. Each zone should be sampled separately at different depths to understand soil composition and nutrient requirements for achieving yield goals. Our senior agronomists in each province create prescription maps tailored to farmers’ equipment and practices, implementing modern agronomy methods for sustainable agriculture. All our senior agronomists are 4R certified, enabling growers to participate in government funding programs.
As per your preference, we can add check strips with a flat rate of conventional fertilizer to the VRT map to monitor the current season’s performance. Based on our experience, this is a useful tool for farmers to assess each zone’s potential. While check strips were widely used at the beginning of the VRT era, nowadays, more and more growers trust VRT for optimizing their yields and efficient resource use.
Currently, it seems that many areas of the Prairies are experiencing a dry cycle. Limited moisture supply makes it difficult to grow profitable crops. It is crucial for growers to decrease the risk factor as much as possible by spending money on crop inputs only based on actual soil tests and accurate management maps.