Four Soil Collection Methods that Actually Work
Without taking the time to perform a soil analysis, it’s nearly impossible to determine what your soil needs to help your crops thrive. While it’s controversial to label any single soil collection method the best, there are four most commonly used methods that work well across most fields. Based on the pros and cons of each, you can determine which tools will help you collect soil samples the most efficiently on your farm.
But before you can get into which type of collection process you want to implement, you first need to determine where you’re going to collect your samples. The area you pull your samples from may depend on soil type, topography, crops grown, or even management history. So the best practice for determining where to start is by using precision soil sampling techniques. Utilizing technology out in the field is the most efficient way to establish a baseline soil nutrient status, assess pH, and develop a smart soil management plan.
Technology such as zone or grid sampling will help determine the overall landscape of your field. Grid-based sampling is insightful if you are looking to establish the base points of a field’s soil health and create zones based on those insights. Zone-based sampling breaks your field up into smaller areas for sampling based on a specific feature such as color or texture.
There are multiple methods to retrieve your soil samples, including the most common four: hand sampling, hydraulic probes, electric probes, and auger probes. Each of these comes with pros and cons.
Hand Sampling Pros:
- Easy to use
- Low initial investment
- Small number of components
- Little to no maintenance
- Labor intensive
- Inconsistent sample depth (hard vs. soft ground)
Hydraulic Probes Pros:
- Fast and consistent depth setting
- Easy to get into the ground Less labor intensive than hand sampling
- Durable and comes with multiple spin settings that are suited for various soil types
- Numerous components – engine, hydraulics (tank, pump & lines), probe, etc.
- High initial investment ($4 to $8k average)
- Fabricated equipment to mount the probe; all parts are typically company-specific
Electric Probes Pros:
- Small number of components -probe and battery only
- Fast and consistent depth setting
- Low maintenance
- No fuel cost
- Easy setup
- More suited for dusty conditions
- Purchase of most electronic parts can be done “off the shelf” without having to be company-specific
- Various electrical parts
- Slower cycle time
- Not always as powerful as hydraulics
- Typically only come with a straight up and down setting
- Battery drains more quickly over time with repeated use
Auger Probes Pros:
- Ease of use in harder ground
- Easy setup – hand tool auger
- More durable than hydraulic and electric probes
- Fewer components – hand or side mount probe
- High contamination risk due to poor probe cleanout capabilities
- Slower cycle time than a hydraulic probe
- Does not typically work well in sandy soils
- Difficult to verify core depth
Take Consistent Soil Samples
When collecting your soil samples, the goal is to get the best results, and the key to that is consistency. Here are the six most critical steps you should take:
- Ensure your soil cup is clean before moving from one zone/grid to another within a field and before sampling a different area.
- Be sure the soil core depth remains consistent throughout the sampling process.
- Take the same number of cores in each zone/grid for every field.
- When filling your soil bag, always keep the amount in each bag the same. Most soil bags will have a “fill to here” line on them, but in case yours doesn’t, make sure every bag has the same amount.
- Pay close attention and label each bag correctly. Whether you’re handwriting your soil bags or using labels, ALWAYS check to make sure you have the correct Grower, Farm, and Field with the correct spelling.
- Finally, remember to verify that you have the correct bag number for your current zone/grid before filling it.
Now that you’ve chosen which soil collection method you want to implement and how it will yield the best results for you, there’s still the elephant in the room—the actual data. No matter how innovative the soil collection and testing technologies are, taking the data those tests produce and translating it into actionable information is still what we are working towards. It’s great if you get a soil map that shows you where all of your nutrients are, but if you have no way to change nutrient application rates, then the data’s usefulness falls short. So, what do you do? Make sure you’re using precision ag tech like Variable Rate Technology. If you don’t already use VRT on your farm, that’s not a problem. The equipment you already have can easily be converted and outfitted with precision ag gear.
Generally speaking, VRT is used to detect information about a given landscape and have a system to make decisions based on that information, right? So then, this technology isn’t merely a productivity tool; it’s also a dynamic one that allows you to take your farm data and make actionable, informed decisions. You should base these types of decisions on a thorough understanding of the farm’s potential, your production goals, and the variability of the fields themselves. Getting help from a consultant or trusted ag advisor can help you navigate those questions.