Soil Point to Yield Analysis
Written by Sawyer Hansen
Updated at November 26th, 2025
Table of Contents
What is the Soil Point to Yield Analysis?
The Soil Point To Yield (SPY) Analysis is a report generated by VRAFY staff that compares the most recent soil test results to the most recent yield layer. The SPY Analysis plots a comparison of the yield to the soil data for each soil nutrient mapped plus several ratios. Rather than looking at the entire zone or grid, it only looks at the yield data close to the point where the soil sample was collected.
How do I get these reports?
This report is available by request, or after the harvest season, we will send it out to our VRAFY Plus customers.
What do these reports mean?
Often, the analysis may show no strong correlations. That is still valuable! This may indicate that the specific nutrient was not the limiting factor for yield. You may have to dig further to look for relationships in the data itself. Look for trends, or lack thereof, that help you set P & K targets when writing prescriptions. Micronutrient-to-macronutrient ratios can also be helpful to review as they may not be mapped.
Digging Deeper
When you see a SPY value you want to analyze further, check out the Compare tool within John Deere Operations Center. This tool allows you to visually compare your soil nutrient layers with your yield maps, or your other soil nutrient layers.
How to interpret your Soil Point to Yield (SPY) Analysis
Step 1: Look for the highest positive correlation
The reports will highlight the three highest correlated nutrients. An upward slope indicates a positive yield response to the nutrient being graphed. In this case, as the Calcium levels increased, so did the yield. After further investigating their pH, this grower applied Ag Lime to increase their calcium levels.
Step 2: Look for “Holes” in the charts
Next, look for values with obvious holes in the charts. In this example, the Correlation is Low at 0.06, but there is a hole indicating that where there was low Bray P1, there was low yield. Further investigation led this customer to use the DAP Crop Removal + Build formula to build the phosphorus in their lower testing areas of the field and limit the applications in the highest testing areas of the field.
Step 3: Look for downward slopes
Downward slopes indicate that as yield increases, the nutrient decreases. We often see this in fields with large variations in yield but have had flat-rate fertilizer applied for years. The lowest-yielding parts of the field were overapplied, causing soil test levels to grow. The highest-yielding parts of the field were underapplied, causing them to drop. This is the perfect time to use one of our Build formulas and get the field back in balance!
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