How to Create a Soil Sampling Plan Using Management Zones?

Learn here how to create sampling locations using Management Zones.

The soil sampling process is generally carried out using georeferenced points (with coordinates) as a reference. These points can either serve as the sole reference for sampling or include sub-sampling points within hexagonal cells. For properties with more intensive precision agriculture practices, many samples are taken according to predefined Management Zones.

Management Zones, also known as Differentiated Management Units (DMUs), are sub-regions defined within a single area. They allow you to visualize areas with higher and lower productive potential within a field, enabling more precise management tailored to each area's characteristics. Since various data mappings will be performed within the boundaries of these zones, it is crucial that soil analyses adhere to the same borders.

Example of Sampling Using Management Zones:

• In WHITE, we see the field outlines and the boundaries of each DMU.
• In YELLOW, we see the central point representing the location where sampling will be conducted for each zone.

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01 - Creating a New Sampling Plan

To generate your Sampling Grid by Zones, you first need to have the SHAPEFILE of the Zones with the Zone IDs properly organized. Check [here] for instructions on organizing SHAPEFILE IDs. Once the SHAPEFILE is ready, click on the New Map tab at the top of FieldScan:

Select the Samples option:

Now, fill out the form that appears on the right side of the platform:

• In Title (1), enter your preferred name using text, numbers, or both.

Next, under (2), you will find three options for New Sampling:

1. Create Sampling: FieldScan will generate a new grid of cells based on the settings you configure.
2. Duplicate Existing Sampling: Allows you to use an existing grid of cells that you’ve previously uploaded to the platform (useful if you want to create a historical series of analyses).
3. Import Point Files: Enables you to upload a SHAPEFILE from your computer containing a pre-created grid of cells.

• In Sampling Type (3), select Soils.
• In Distribution Type (4), select Zones.
• In Farm (5), select a farm you have already registered on the platform and then choose the Field (6) where you want to insert the zones. You can create grids for multiple fields simultaneously, as long as they are registered under the same farm.

Finally, click Next (7).

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02 - Grid Parameters and Base Map

Zone-based sampling relies on distributing main points within each zone and a custom number of sub-sample points contained within the zone boundaries. Zones must be predefined and prepared in a SHAPEFILE format. Click the Zones (8) button, and in the window that appears, select the file containing the management zones (upload the SHP, SHX, PRJ, and DBF files simultaneously).

In (9), choose the type of planning you want to perform: Samples or Sub-samples.

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2.1 - Sample Planning

• In (10), set the number of central points per zone.
• In (11), define the starting number for your sampling. For example, you can generate points with labels starting from 1 and incrementing up to the number of points/sub-samples you’ve defined, or you can choose a different starting number for labeling.

Tip: Enter or use the arrows to set the Number of Points per Zone (10) and the Starting Number (11), then click Apply.

Once you’ve defined the number of points per zone and their labeling, the next step is to customize the point grid. However, before proceeding, it’s helpful to apply a base map.

A base map can include vegetation index imagery such as NDVI, NDRE, or VARI (from satellites or drones), zones, or soil analysis interpolation maps. At the center of the screen, there is a box labeled Mappings (12). Select one of the available maps to serve as the base.

This type of map provides an overview of your field and helps you identify zones of interest or areas that won’t be sampled. Selecting the correct base map is crucial. Use the Filter Maps (13) box to access the appropriate base map and date.

For more specific results, you can, for example, choose which nutrient to display on the interpolation base map by using the Visualization (14) box:

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2.1.1 - Modifying the Sampling Point Grid

The base map is also ideal for providing insights into your field's health and overall condition. It allows you to adjust the grid by moving points to areas of interest (where no points were generated) or removing sampling points from locations where results may not be useful, such as:

• Drainage areas
• Proximity to fences
• Points near field boundaries
• Livestock feeding stations
• Areas with a history of good nutrition
• Lime dumping zones

You can add, remove, or reposition points within the zones.

• To delete a point, click on it once, then click the trash icon in the upper-right corner.

• To add a point, click the inverted drop icon (15), choose a location on the map, and click once to place the point. You can add multiple points at once. When finished, click the ✅ icon to confirm the addition:

• To move a sampling point, click on it and drag it to the desired location:

Once you are satisfied with the grid adjustments, click Next (17) to proceed with selecting depths.

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2.1.2 - Choosing Depths

The points within the zones are defined by both their labels and the depths at which the sampling will occur. Typically, sampling is performed at depths of 0–20 cm and 20–40 cm. Here's how to set the depth ranges for your points:

In (18), you can define the minimum and maximum depth ranges for sampling, as well as the percentage of points you want to sample within that depth range. For example, if you want 100% of your points sampled in the 0–20 cm depth range, enter 0 in the first box, 20 in the second, and 100 in the last box. You can type the values directly into the boxes or use the arrows to adjust them:

You can add additional depth ranges by clicking on (19). To delete a depth range, click the trash icon next to that range.

Once you're satisfied, click Submit (20) to save your sampling plan:

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2.2 - Sub-sample Planning

In (9.1), choose Sub-sample as the Planning Type.

In (10.1), select the number of sub-samples per zone.

In (11.1), define the starting number for your sampling. You can generate points with labels starting from 1 and going up to the number of points/sub-samples you’ve set, or you can choose a different starting number for labeling.

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2.2.1 - Modifying the Sub-sample Point Grid

The base map is also ideal for providing insights into the health and overall condition of your field. It allows you to adjust the grid by moving points to areas of interest (where no points were generated) or removing sampling points from locations where the results may not be relevant, such as:

• Drainage areas
• Proximity to fences
• Field boundaries
• Livestock feeding stations
• Areas with a history of good nutrition
• Lime dumping zones

You can add, remove, or reposition sub-sample points.

• To delete a point, click on it once, then click the trash icon in the upper-right corner.

• To add a point, click the inverted drop icon (12.1), choose a location on the map, and click once to place the point. You can add multiple points at once. Once you’re finished, click the ✅ icon to confirm the additions:

• To move a sampling point, click on the point and drag it to the desired location:

When you're satisfied with the adjustments, click Next (13.1) to proceed with selecting depths: