With much of the upper Midwest receiving excess rainfall in June and early July, a few customers have asked us to help them use imagery to identify and measure the area affected by this water damage. Following the steps below, this can easily be done from within the John Deere Operations Center.

Please note that this assumes the poorest parts of the field are from water damage. We have no way to differentiate water damage from other crop damage, so it is still best to scout fields in person. However, this is a quick and easy way to get an idea of where to go and the extent of the damage.

Also, the steps below will show how to do it on the website, but it works the same way if you want to do it on the John Deere Operations Center mobile app.

• Start by bringing up an imagery layer using the Field Analyzer Tool within the Operations Center. It will be labeled as “Crop Sensing” in the drop-down.  NDVI works for most customers for this, but feel free to check out the other imagery layer types to see if one better matches your fields.  Note: When viewing the layer, it will show the percentage of the field in each gradient. When looking for damaged areas on an NDVI image, the lowest values (typically red), will indicate where the crop damage has occurred. To calculate the acres, we will use the VRAFY prescription tool to tell us the acres for each colored part of the field.
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• Under the map, locate and click on the Create Manual Rx button.
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• In the new window, under the Classify Settings, change the Zone Type to “Colour Breaks”, then click Run Rx.
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• You will now see an acres total for each of the Color Breaks on the map. You can repeat this quickly across all of your fields. If you close out the window here, it will not save the prescription.
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• As a bonus, you can save this as a prescription for later use if you add a Product and Rates. For example, if you want to skip fungicide applications where the crop has drowned out, set the lowest colored zone(s) to zero. Then set the rest to your standard rate. Press Save Shapefile at the bottom, and you will have just created a quick and easy variable rate Fungicide Map!
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• Here is the view in the Operations Center of the previous map as a Fungicide Prescription. I set the water-damaged spots to zero and the rest to my standard rate of 10 GPA.
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Using satellite imagery from VRAFY in the John Deere Operations Center makes it quick and easy to determine the extent of crop damage after a major event, like the recent flooding. If you have any questions, feel free to reach out to VRAFY support at 507-800-0898 or click here to schedule a meeting with one of our awesome team members!

Southeast, South Dakota, along with the majority of the Midwest region of the United States, has seen substantial amounts of rain the past couple of weeks. Crop health, flooding issues, and fertility are a few of the things to worry about when dealing with these big rain events. As the rain passes and fields begin to dry out, you should take some time to drive around and assess the current conditions you are up against.

Washouts, sitting water, and flooding are many of the common issues that have followed this previous rain event. When thinking about fertility, it is important to understand the leachable nutrients. Rightfully so, nitrogen is a commonly talked about nutrient when referring to leachability. To know how much you have, taking nitrate samples is something to consider. Of course, there may be acres on every farm that yield zero, but it is important to not give up on the acres that still have a chance to yield high.

Depending on your soil type, nitrate moves six inches down the profile for every inch of drainage. In some places, we have gotten ten inches of rain or more. With this rule, it is safe to assume that nitrate has moved sixty inches down into the soil profile. V8 corn is commonly referred to as about 24 inches. This means that with this recent rainfall, we lost a good amount of nitrogen. It is understandable to be stressed and discouraged by the current situation, but staying positive in a tough situation is the most important thing to do. We highly encourage you to spend a couple of bucks and sample your fields to see how you are sitting on nitrate levels going forward this growing season.

As farmers navigate the challenges of tighter margins, efficient fertilizer management has become more crucial than ever. When growing corn and soybeans, phosphorus costs can significantly impact your bottom line. Let’s explore how to make every dollar count.

Crop Removal Approach: A Smart Choice

Even without soil tests, research suggests that the Crop Removal method is an economical way to manage phosphorus. Here’s how it works:

• Estimate the amount of phosphorus removed from the field through grain harvest.
• Replace that phosphorus using variable-rate fertilizer application.

The University of Nebraska-Lincoln Study

In a comprehensive 15-year study, researchers at the University of Nebraska-Lincoln examined three phosphorus application methods for corn:

1. Crop Removal Only: Focused on replacing phosphorus based on crop removal.
2. Build Program: Targeted different soil levels of 15, 30 and 45 ppm
3. Deficiency Correction Program: Build to a target level, then apply crop removal. Reduce crop removal in high soil test areas.

Key Findings

• Crop Removal emerged as the most cost-effective strategy over the study period.
• A secondary finding identified a need to reduce applications when soil test levels are higher than 40 ppm (as measured by soil Bray P1 test).

Crop Removal Recommendations with VRAFY

Sign up for VRAFY today to access crop removal recommendations for phosphorus. Using yield maps, we can automatically generate prescriptions for as little as $1 per acre. No advanced skills required—just provide your yield data and fertilizer preferences.

Remember: Sometimes less is more, especially when it comes to phosphorus management.

Source: https://acsess.onlinelibrary.wiley.com/doi/10.2136/sssaj2018.02.0068

One of the benefits of having your data in the Operations Center is that it becomes easier to view the layers side by side. This allows you to see how the decisions you made throughout the year impacted the results on the yield map. It also allows you to see how the soil test results compare to the yield results in your field. You will see how easy it is to compare your yield map to your soil test results in a few steps.

For additional details for each step, check out our Knowledge Base.

1. Start by bringing up a” Soil Test Results” layer within the Field Analyzer tool on the Operations Center website. This tool currently does not exist in the mobile app.If you do not have soil test results in your Operations Center, please contact VRAFY so we can discuss how to add them to your Operations Center Account.
   
2. Next, click on the “Compare” button in the upper right.
   
3. At this point, a second drop-down list will appear where you can choose your second layer. For example, we will compare the “Yield Layer” for Corn in 2023 against our soil sampling results.
   
4. Once you view your layer, you can zoom in and out or move around the field, and both maps will stay coordinated. Our example shows that the soil K (Potassium) has been accumulating in the southern areas. Over the years, uniform application rates were used across the entire field. This practice inadvertently led to an excess buildup of potassium in this part of the field.
   

Comparing layers side by side is quite easy in the Operations Center and can help you visualize relationships between multiple factors and how they impact your yield.

If you do not have your soil test results or satellite imagery in the John Deere Operations Center, sign up with VRAFY today to get them added!