Get to Know What Lives in Your Soil

Healthy soil is the foundation for productive crops and a resilient farming system. When it comes to building soil health, we often talk about the physical and chemical properties of soil – things like soil texture, aggregate stability and soil organic matter. There is a third component of soil health, though, that is highlighted less frequently: the biological component.

At its most basic level, soil is made up of weathered rock material, water, air, and the remains of decomposed plants and animals. Beyond that, the soil is an entire functioning ecosystem full of life! In just one handful of soil, there can be billions of microorganisms, including some you’re probably already aware of, like bacteria and fungi. 

Other living organisms in the soil can be classified as invertebrates. An invertebrate is simply an organism that does not have a backbone. Some common soil invertebrates include mollusks, earthworms, arthropods (i.e., insects, spiders and crustaceans), and nematodes. Soil invertebrates living beneath the soil surface may be harder to detect, but by familiarizing yourself with the most common invertebrate groups, you can be sure you won’t underestimate their impact on soil health and agriculture.

Arthropods and Earthworms

The role of arthropods and earthworms in agriculture is well-established. Arthropods, at the soil surface and beneath, are great decomposers and nutrient cyclers. Arthropods that feed on plant residue help to build soil organic matter and can impact soil fertility. Soil-dwelling arthropods can be pests (e.g., cutworms or white grubs), but they can also help to control pest populations. For example, ground beetles and spiders are arthropod predators that are often encountered in fields. 

When earthworms move through the soil, they create channels that can help improve soil drainage. Earthworms also enhance soil structure and nutrient cycling through their movement and feeding habits. Scouting for earthworms is fairly simple and can be done by counting the number of earthworm middens on the soil surface. An earthworm midden is a small pile of plant material and worm castings (worm poop!) that can be found at the entrance of a worm burrow. The photo below shows five earthworm middens in a no-till field. Click on the link below the photo for more information. 

Earthworm Middens

Credit: Sjoerd Duiker via No-Till Farmer

Nematodes

Nematodes – or microscopic roundworms – are lesser-known organisms in the soil. Plant-parasitic nematodes can be agricultural pests that impact plant health and yield by sucking out the contents of plant cells using piercing, needle-like mouthparts. This type of nematode can also vector plant diseases, such as tomato mosaic virus. There are also beneficial nematode groups that are present in healthy soils, such as bacteria feeding, fungal feeding, and predatory nematodes. 

Nematode feeding damage is often misidentified as a nutrient deficiency in crops; plant symptoms – such as chlorosis, stunting, and wilting – are common examples. While some nematodes, like Soybean Cyst Nematode, can be visible on plant roots, most nematodes will require positive identification through a soil sample. When soil sampling for nematodes during the growing season, use a soil probe to sample 6-8 inches deep and sample at the base of the plant in the root zone. If sampling outside of the growing season, fall is the best time for detecting nematodes because populations will be at their highest.

Some plant-parasitic nematodes are very common and can be found in nearly every soil type or cropping system (root lesion and stunt nematodes [see picture below], for example). Generally, these nematodes will rarely cause economic harm to crops. Some nematodes, however, are more specific to a soil type or to the crop they are attracted to. Two examples of harmful plant-parasitic nematodes are Soybean Cyst and Corn Needle (see picture below) Nematodes.

The head of a Corn Needle Nematode. This nematode feeds almost exclusively on corn roots and the economic threshold is just 1 or 2 individuals in 100 CC of soil (about a handful of soil). 

Stunt nematodes are plant-parasitic nematodes that feed on field and vegetable crops. The economic threshold for stunt nematodes varies by crop and soil type, but is 100-200 individuals in 100 CC of soil (about a handful of soil) in corn.

Time to Dig In

The soil is a living, functioning ecosystem full of organisms you can and can’t see. Microscopic or not, these organisms can have a big impact on your productivity. The next time you’re out in the field, keep an eye out for signs of earthworms and other invertebrates that can be seen with the naked eye. And, if you are interested in learning more about soil invertebrates on your farm, reach out to your SHP field manager or your local agronomist to explore scouting and soil sampling options.

Jason Lay

Jason is the third generation in his family to farm this land. After working in the corporate world, Jason had the opportunity to buy out his uncle and began farming the 2,500 acre farm in Bloomington-Normal, Illinois full-time in 2003.

The Lay farm grows a rotation of corn and soybeans. For the last nine years, Jason has utilized strip tillage for his corn acres. He added no-till on soybeans in 2011. Jason has also added cover crops to his practices, primarily using rye grass, and occasionally oats and crimson clover. He currently has 200 acres in cover crops.

Increased testing is one of the biggest improvements Jason has made in his farming practices—testing soil and stalk nitrate levels. Jason also uses Variable Rate Technology to precisely target what his soil needs in nutrients and when.

“I am personally impressed with the partners that have come together as part of the Soil Health Partnership. Corporate partners, conservation partners and farmers—all working together toward the same goals. I plan on farming for a long while, and we have to be smarter as an industry how we do things. I can help bring about that change by adopting new practices and setting an example for others to follow.”

Kirk Kimble

Kirk and Tiona Kimble are the fifth generation farming their 2000 acres in Chillicothe, Illinois. They are invested in preserving this family heritage for their three daughters, all of which help on the farm today.

Kirk has used numerous covers and combinations through the years: cereal rye, annual rye, vetch, oats, radishes, sunflowers and sun hemp. He puts a cover crop on every acre.

“I know I have my topsoil and it isn’t washed down the river. It’s a justifiable cost,” he said.

Kirk also practices no-till on every acre. When Kirk began farming, he tried no-till to save money by not purchasing more equipment, and he liked the results. With the big rain events occurring more frequently, Kirk says it just works well on his land for keeping erosion at bay.

He soil tests regularly, and depending on the results, does either variable rate or blanket rate application of nutrients. He does not do fall application of nitrogen.

“I believe in the practices that I have implemented, but the Soil Health Partnership is documenting them scientifically,” said Kirk. “I like seeing what is happening in my soil, year over year, and understanding how I can make it better. I like being part of a group that is promoting soil health and conserving our soil resource.”

Understand the Health of Your Soil Through Infiltration Testing

Understanding the health of a particular soil may also help explain other things that are happening in that field.  In our area, a rainfall event of three inches or more at some point throughout the summer is not uncommon.  But what’s more important than the rain itself is what happens to the rain once it reaches the soil.

Taking a drive to look at your fields will tell part of the story. Did that rainwater runoff the surface, stay on the surface to create a puddle or did it soak into the soil pores?  This ability for soil to take up water and allow movement within the soil profile is how the National Resource Conservation Service (NRCS) defines infiltration.

The infiltration of your soil can be affected by many factors and how water infiltrates your soil can be even more complicated. What if there was a way to understand where water goes and how healthy your soil is by using a basic infiltration test? There are kits available to get highly accurate tests that can translate across many fields, but for our purposes, let’s use supplies you probably have on your farm.

A shovel is the number one tool that I use when looking at soil health. Just digging up 6 inches of soil can tell you about the history, structure, and drainage ability of that soil. Does the soil crumble between your fingers or does hold together?  Are there any hardpan layers that may have been caused by tillage?  We can learn so much by digging into the soil.

That structure within the soil directly affects how water is either absorbed or runs off during rainfall events.  We are able to compare different soils and how they are affected by rainfall with an infiltration test.

Supplies:

  • Shovel
  • Rubber mallet
  • 2 PVC or Steel rings with 6 inch diameter
  • 2 water containers filled with 444 mL of water
  • Plastic wrap
  • Timer

To get started, figure out what your goals are and which soils you want to compare.  Start on one soil type and pound the first ring in with the mallet halfway into the soil.  It works best to pre-measure the rings and put a mark on the halfway point to signal how far the ring will go into the soil for the test.

    1. Start by pounding your ring in with the rubber mallet.  If the ground is on the harder side, a board across the top might help.  Pound the ring halfway until you get to your mark.
    2. Place plastic wrap inside of the ring.  This will help prevent splash effects that could happen when pouring in your water.
    3. Take your pre-measured 444 mL of water and pour into the plastic wrap inside the ring.  This represents an inch of rainwater.
    4. Start your timer as you slowly pull the plastic wrap off of the ring to let the water soak into the soil on the inside of the ring.
    5. Keep an eye on your ring and stop the timer once the water has completely soaked into the soil.  There will be a shimmer on top of the soil.  Record the number of minutes it takes for 1” of rainfall.  Repeat steps 2-5 a second time to represent a second inch of rainwater.
    6. Repeat this process for your secondary location.  This might be a different field, soil type, part of the field that was managed differently.  Be consistent in the process and record 1st and 2nd infiltration numbers to compare.
    7. Dig up your rings and compare the soil at the bottom of the ring.  Did the moisture reach the bottom?

Once you’ve finished your tests, what differences can you pick out between your soils?  Is it the difference in tillage practices?  Was one of the fields harvested too wet in the fall?  Does one currently use cover crops?

A soil that has slower infiltration rates is more likely low in organic matter, more easily has runoff in large rain events, and can hold less water in a drought situation, so what management changes might you make based on your in-field infiltration testing?

Don’t worry about having exactly a 6-inch ring or 444 mL of water for your own in-field testing.  At the end of the day, this test is meant to be a learning experience and a great way to compare one field to the next.  Make sure you are consistent and continue to use the same tools and you should learn a great deal about your soils!

shovel and soil                                   infiltration test

 

infiltration test               infiltration test

The Dos and Don’ts of Soil Sampling

Soil sampling can be a great step in the pursuit of healthier soils, but it is not always easy to get soil sampling right. The correct procedures yield the best data, and the best data helps farmers achieve the healthiest soil.

But how do you get the best data?

Dr. Nick Ward of Ward Laboratories, Inc. helped farmers understand how to best sample soils on their farm in an April 28 Soil Health Partnership (SHP) Soil Sessions webinar, “Quality in, quality out: the Dos and Don’ts of Soil Sampling.”

Most importantly, Dr. Ward reminds farmers that data is knowledge. The data available from proper soil sampling can impact future fertilizer applications, environmental compliance, diagnosis of problems, and overall sustainability. The question is not should I sample my soils, but how can I best sample my soils.

“You can’t make good decisions without data,” he said.

Farmers have numerous opportunities to make specific choices about how they will collect the soil data from their farms. Soil sample depths vary. Some farmers work from a 0-6” depth and some from a 0-8” depth. Dr. Ward teaches that “constant depth is the most critical thing when we’re out soil sampling.”

Whatever depth you choose, just be sure to be consistent throughout the field and year over year to provide the best data. And when you are thinking about testing before or after tillage, just remember that consistent depth is paramount, so sample the same every year in a way that you feel most confident you are achieving a consistent depth.

Soil sample locations can vary. Many farmers chose to sample in a grid pattern, taking the samples where the lines of the grid overlap. This allows for the sampling of the same exact location over time in order to pinpoint changes in the soil, but some farmers choose to sample more heavily in certain zones or problem areas. Still, other farmers composite sample their fields, meaning they select the areas of the field to sample at random.

“Composite sampling should be doable for just about everybody,” Ward said. “Grid sampling is the most intensive practice, but it’s going to give us our most robust data set to make decisions from.”

Your soil health strategy should inform the decisions you make for how and where to sample. The most important reminder is to always be consistent.

How often should you sample? It will depend on your sampling strategy, says Ward.

“If you do something more intense like multiple zones or a grid sample, maybe doing that every 3-4 years would be a good practice.  But if you are not going to build a dense data set spatially across your field, maybe it is more important to take a dense data set in time.  So, that’s sampling a composite every year in different spots.”

This one-hour webinar will answer many questions and help farmers really nail down the sampling strategies that could work for their farms and soil health goals, as well as guide them with the return on investment for the effort.

Check out other SHP Soil Sessions here.

Quality In, Quality Out – Dos and Don’ts of Soil Sampling, Hosted by Dr. Nick Ward

Join Dr. Nick Ward, President of Ward Laboratories, Inc. for a Soil Session discussing soil sampling. During this webinar we will discuss the need for soil sampling and various soil sampling practices, including:
  • Sample and sub sample numbers, sample depth and sample location
  • Tools for successful soil sampling
  • Costs to soil sample
  • Plant sampling

Soil Sessions is a webinar series by the Soil Health Partnership that provides monthly, in-depth updates on various SHP programs and research findings. Soil Sessions covers a range of topics such as our evolving data insights, how SHP manages and integrates data, our connection to and work with our partners, as well as providing technical information on topics like cover crops, scouting and grazing. To view all SHP webinars, visit our website here.

SHP Dives Deeper Into Soil Health Testing

The Soil Health Partnership (SHP) takes soil sampling and testing very seriously. SHP administers higher resolution grid samples, pulls more depths of soil, and dives deeper into soil health testing than most agronomy specialists. We can do so because this is the focus of our team: giving farmers more data to help make long-term management decisions.

Over our five-year program, we measure and record visual observations through crop scouting and measuring and recording soil properties that can only be understood through soil testing. Typical trials that occur on-farm usually only measure yield. This is where the uniqueness of the SHP program begins to shine. SHP goes more in-depth with the annual soil sample and the bi-annual soil health samples.

What does SHP measure?

  • Chemical Soil Sampling: SHP does these tests in much higher resolutions than most agronomy specialists. For most soil samples, you are looking at a zone sample or 2.5 acre grid. Within our research, we are studying these same soil characteristics at a 1-acre grid sample resolution, or even smaller. Most test replicated plots are not this large either. With the larger plot size and higher resolution, we are afforded the opportunity to generate more data and observations throughout every growing season.
  • Soil Health Testing: This is where SHP invests more time and goes more in-depth than most trials. SHP looks at soil health on each strip in Partner Fields, usually eight strips per field. We continually track aggregate stability, water infiltration, active carbon, different soil proteins, soil respiration and more. Many farmers are not currently doing soil health tests. More often than not, growers do not know that these kinds of tests exist, what they do, or how to use the data. They require more time and are more labor-intensive to acquire than periodical soil testing. These tests and findings typically do not drive annual decisions, but builds a data set over time. Soil health practices provide long term information on adapting inputs and making amendments to soil and management practices.

Results from these tests are reviewed with SHP on a consultation-based approach. It is not about the here and now. Soil health testing requires a different cadence than the annual cycle that most of us are accustomed to in farming.

Together, we must stay focused for the long term, to not only make sure we acquire the information on soil health annually but also that we know what to do with the information that is collected. Soil health data is beneficial to review each year to understand the ebb and flow of your field, but annual management changes should not be driven by the data.

Tracking Better Data

Data is a powerful tool in your operation, and we often look at our yield and soil properties as the most valuable. It is important to remember though, the real value of soil health data is not in any one sample. The value is being able to look at the changes over time and applying it to other data sets. Looking at the management, yield and the ancillary pieces help to make inferences about the manner that it changed. This starts with having a complete data set that you have confidence in and begins with taking the time to do things the proper way so you have data you can trust for years to come.

How do you go about tracking better data?

  • Knowing and following proper soil sampling procedures is essential to securing accurate data, no matter the agronomy partner or lab you are working with. Knowing what your lab wants for a volume of soil, making sure it is stored and shipped correctly, and submitting the proper information, such as the correct depth of your sample, are key to accuracy. It is ok to change your sampling procedures or even your lab, but it must come with communication. Open communication with your partners insures that everyone understands how important it is to have consistency in what you are testing for and how you go about it when it comes to soil health.
  • Working with a trusted team of partners. Improving soil health or any management practice on a farm is a task that can be done all by yourself, but is often more successful with a team of people working together. This team should be assembled by pulling in the best people and information you can find. Information from different sources keeps farmers performing at a high level. Think about the top athletes like LeBron James or Tom Brady. They do not rely on just a single sports medicine doctor to keep them performing at a top level. They have a team of individuals, people that focus on nutrition, regeneration, health, mental health, training, and of course marketing managers that make them successful. Isn’t the same really true of our ag producers?
  • Calibrating yield monitors before each harvest season. The data collected each year plays a huge role in your decision-making process. Knowing and following your procedures for yield monitor calibration is key to securing the most accurate calibration.

One of the long term goals of the Soil Health Partnership (SHP) is to have a hand in the creation of decision tools that help growers know the likelihood of success of implementing different practices on their farm is relative to a number of factors that make each operation unique. It is only with the ability to take the data over the long term and make accurate predictions that we can move forward with that goal.

The long-term draw of soil health and working with SHP is to make decisions easier in the future than they are today. If we apply data-driven principles going forward, better management decisions can be made, not just for our economic well being, but also for the health of our soil, and our license to operate for generations to come.

Soil Sampling: What Are We Measuring, Seeing and Interpreting

In this Soil Sessions Webinar, we discuss why SHP soil samples, give an introduction to soil health and soil health indicators, and describe the SHP soil sampling procedure.

During this webinar you will learn:
  • Our soil sampling protocol
  • How we are measuring and storing our data
  • Specific interpretations from our current soil samples

Soil Sessions is a webinar series by the Soil Health Partnership that provides monthly, in-depth updates on various SHP programs and research findings. Soil Sessions covers a range of topics such as our evolving data insights, how SHP manages and integrates data, our connection to and work with our partners, as well as providing technical information on topics like cover crops, scouting and grazing. To view all SHP webinars, visit our website here.