Soil

Take It Outside: Onetime Indoor Ag Pioneers See Opportunity Out In The Field

Tue, 07 Oct 2025 12:16:34 GMT

For the past year, the team at Soil Action has been working toward building an artificial intelligence driven product to sense soil nutrition in real-time. Whereas other companies have attempted to revolutionize soil testing before, co-founders Jack Oslan and Nate Storey say the AI tools available today are making what was once difficult or nearly impossible, possible.

“Soils are unknown and misunderstood,” Storey says. “We can use AI to understand soil better, and our goal is to come up with the instruments to solve the problem.”

Soil Action’s solution in progress includes building models and training models pairing near infrared spectroscopy with AI. Its goal is to reengineer the traditional process of sampling, shipping, agronomic recommendations, prescription files and applications while making it all in real-time. They are doing on-farm demonstrations this fall.

Before founding Soil Action, these two businessmen first met 12 years ago co-founded indoor agriculture startup Plenty. Storey’s time at Plenty was applying his laser focus on yield with innovation in algorithmic nutrition.

“I went into indoor ag because it was an area with the largest opportunity to drive yield. I have a lot of interest in yield,” he says. “In indoor, you can control everything and measure it–everything can be known in those systems and control every part of the process: root zone temperature, gas composition, and more.”

Now, Storey and Oslan want to bring those learnings outside and into the field.

“We got really good at understanding how to take an algorithmic approach to yield. It’s about understanding the yield equation, breaking it apart, optimizing individual aspects, and restacking them,” Storey says. “In row crops, the soil is the most important part, and to solve the yield equation we have know the variables that correlate and then begin to manage.”

What Does The System Look Like?

Currently, the beta version product is housed in a 3”x6” steel tube which can be mounted on any style of implement or equipment to automatically take measurements 4” to 6” deep every 50’.

(Soil Action)

“The real end goal is to have every equipment cab be mounted with an AI enabled agent to give you real-time measurements of what’s going on in your field,” Storey says. “It’s an AI agent focused on optimizing yield.”

The first testing was conducted in northern Iowa.

“We’re building our models on data collected from the field, and we’re using deep learning to ingest all of the information and help understand correlations,” Oslan says. “We can see everything that’s there, but we don’t understand everything that is there. That’s a focus for our work right now.”

“Holy Grail of Soil Sampling”

When it’s ready to be commercially available, Soil Action aims to provide results measuring two forms of nitrogen, phosphorus and potassium. Other crop nutrients will be added in the future.

“Every expert we talked to said we couldn’t use NIRS in soil sampling, but the physics said we could,” Oslan says. “We took two intensive weeks using sand and manipulating it for measurements with NIRS, and our deep learning models can untangle data in a way classical statistical methods cannot. Now, it’s about how fast we can solve for soil nutrients with these newer tools.”

Soil Action says it aims to provide the equipment to farmers for a hardware fee of $10,000 paired with a subscription for the analysis on an annual fee basis.

Biodiversity Index in the Field: A Look at Diagnostic Microbiome Tests for Soil Health

Tue, 15 Jul 2025 21:13:30 GMT

In the past few years, about a handful of companies have emerged with tests to measure a soil microbiome of fields, give a biodiversity index and help farmers understand the effects of inputs on soil health.

All of these companies recognize the complexity of a soil’s biology, and they aim to bring new tools to advance regenerative agriculture. Different from chemical and physical soil tests, which are often used to gauge what the soil needs (for example, rates of nitrogen), microbiome tests can provide insights on what the soil can supply (for example, nitrogen fixation or decomposition processes).

And these companies see the microbiome soil tests as complements — not replacements — to traditional soil testing.

Biome Makers

With a goal of delivering agronomic insights, Biome Makers built its BeCrop technology pairing soil microbiome knowledge and machine learning. The company, which is based in northern California, currently services farmers across 2.2 million acres and six continents. The BeCrop Test provides a report on nutrient cycling, health and biodiversity to be used to improve yields, monitor nutrient cycling, and predict disease risks. ( biomemakers.com )

EarthOptics

Launched as Pattern Ag and now part of EarthOptics, this platform claims to provide farmers a predication of key field agronomic outcomes with more than 90% confidence. The company uses DNA sequencing to provide soil biological test results. It also offers a premium program combing the soil microbiome results, with sensor data, yield data and satellite imagery for soil fertility and crop planning. ( earthoptics.com )

RhizeBio

Based in North Carolina, RhizeBio says its test uses a proprietary bioinformatics pipeline to translate raw soil DNA sequencing data into soil health reports both informative and easy to use. The results can be bucketed into three groups: biodiversity, bioindicators and risk analysis. The RhizeBio report provides biodiversity data including the number of species within the soil’s microbiome, community evenness, primary members and functionality. This gives insights on a soil’s capacity in stress environments such as droughts, disease, disturbance rating and nutrient cycling potential. ( rhizebio.com )

Trace Genomics

Recently acquired by Canada-based Miraterra, Trace Genomics was founded in northern California and has a soil analytical lab in Ames, Iowa. The Trace Genomics testing uses DNA sequencing to provide insights on the soil microbiome. The technology combines soil science, genomics and machine learning to output a measurement of a soil’s bacteria and fungi. Combining those measurements with chemical properties, growers receive information on a soil’s health and productivity. The company also offers a year-round sampling program to help guide seed selection, input selections, fertility products and biologicals for 70 crops and more than 225 pathogens. ( miraterrasoil.com/trace )

Guest Commentary: The Challenge of Going Beyond Sustainability

Fri, 13 Nov 2020 05:59:05 GMT

Healthy returns to the land are not enough. Healthy institutions and policies are critical.

By William J. Richards

If we’re going to feed and fuel an estimated 9 billion people by 2050 without degrading our environment, U.S. leadership is critical and time is short. Simply achieving “sustainability” is not good enough. We must have the research, technology and production practices to go beyond sustainability. Achieving this goal will require a new vision for U.S. agriculture, forestry and conservation. Solutions from the Land, www.sfldialogue.net , is a serious effort to begin building that vision.

Solutions from the Land recently released a report, “Developing a New Vision for U.S. Agriculture, Forestry and Conservation,” that articulates the big picture, documenting the current state of land use and providing a vision for the 21st century. I congratulate the team and the sponsors for an excellent report. But, as a farmer and a former chief of USDA’s Soil Conservation Service, now the Natural Resources Conservation Service, I’d like to join in with some “here and now” opinions.

If we are to achieve and surpass sustainability we must:

improve and enhance our soils;
improve and expand our current water resources;
provide better habitat for wildlife;
provide food and fuel to our citizens and exports to the world;
provide society with numerous ecosystem benefits, including clean air and water; and
protect the environment.

It starts with soil. First and foremost we must remember that productivity begins with the soil—maintaining and enhancing its health is key to sustainable land use. For centuries, technology and global expansion of cropland has meant that agriculture’s productive capacity has almost always exceeded the demand for food and fiber.

Declining prices for commodities and low rates of return to the land contributed to a lack of investment in soil conservation until the Dust Bowl led the federal government to begin a concerted soil conservation effort with the creation of the Soil Conservation Service in 1935.

While the role of federal, state and local governments is important, so are healthy rates of return to the land. In this context, renewable energy plays a vital role and can be the “bridge” to develop and enhance our soil and resource base. We all know what renewable energy has done for the Corn Belt and the ag economy. But corn is food, and the world needs food. We must continue the research and development of cellulosic ethanol and find ways to better use biomass from our fields and forests.

Accountability forward. Healthy returns to the land alone are not enough to take us beyond sustain-ability in the future. Healthy institutions and policies are also critical.

The Solutions from the Land report emphasizes the need for metrics to measure environmental performance. As farmers, we need a certification system that identifies and rewards producers for environmental stewardship. Australia does this well with Landcare. Our Conservation Security Program could offer performance-based benefits. But in order to reward producers for changes and improvements, we need to do a better job of measuring key indicators of sustainability such as air quality, water quality and biodiversity.

Conservation compliance, introduced in the Food Security Act of 1985, encouraged us to adopt conservation tillage, no-till and other practices that have greatly reduced erosion and improved economic returns. Compliance is only a condition of eligibility for USDA program benefits, not a legal requirement. If federal farm policy shifts away from commodity programs toward crop
insurance programs not covered by conservation compliance, which appears likely, the incentives for continued investment in conservation will be reduced.

Crop insurance is voluntary and farmers do pay premiums, but the premiums are significantly less thanks to federal subsidies. If we, as farmers, are to receive the extra benefits, paid with tax dollars, then we should meet conservation standards. I know this is a controversial issue, but we need to be part of the dialogue. Conservation compliance is not regulation, it’s regulation prevention.

Finally, I believe the most important farm “subsidy” I’ve received was an education at a land-grant university—The Ohio State University. The research, Extension and education system is what made and keeps U.S. agriculture the envy of the world. As cited in the Solutions from the Land report, research, Extension and education should be a top priority if we want to go beyond sustainability in the 21st century.

William J. Richards is an Ohio farmer who served as chief of the USDA Soil Conservation Service (now Natural Resources Conservation Service) from 1990 to 1993.

Restoring Soil Health Takes Time

Fri, 13 Nov 2020 06:04:10 GMT

After rapid gains from vertical tillage, pH and fertility, the improvement pace slows down

Another year of results from a long-term comparison of healthy and unhealthy soil in central Illinois confirms the trend:

Improvements in soil health can be documented in just a few years, enough to move yields from unprofitable to profitable.
The fastest improvements involved fertility and pH (the chemical aspect of soil health) and eliminating compaction (the physical aspect).
Improvements in the biological aspect of soil health take longer.
Restoring abused soil to health might take a very long time.

This past year’s results provided more good news—but the improvements were less dramatic than Farm Journal Field Agronomist Ken Ferrie, who is conducting the study, had hoped. The 2016 results showed, in some situations, even small soil health improvements from a single year of cover cropping might impact yield.

The study involves two farms about a mile apart—Farm A and Farm B. Both farms primarily contain two types of soil. One is a lighter silt loam, with about 3% organic matter content and a cation exchange capacity of 15 to 16. The other is a heavier silty clay loam. The organic matter content of that soil is 4% or more, and the cation exchange capacity is 20 to 25. If both soils were in perfect health, the silty clay loam would always outyield the silt loam because it has higher natural fertility and water-holding capacity.

The soil on Farm A has always been well-cared-for and healthy, but Farm B had been abused for 30 years, resulting in unhealthy soil. The practices used on both farms were similar except the operator of Farm A no-tilled. The operator of Farm B disked soybean stubble before planting corn, which destroyed soil structure and left an impermeable compaction layer.

The soil on Farm B also had become very acid. Because of these factors, the unhealthy soil on Farm B had more erosion, slower decomposition of residue and poor water infiltration.

In 2011, the new operator of Farm B set out to restore its soil health. He used vertical tillage to remove sudden density changes and compaction. He also aggressively applied lime to build up soil pH. Ferrie calls that “shooting the slow rabbits first” because these changes are the easiest to make and they produce quick improvements in soil health and yield.

“The vertical tillage used to fix physical problems helped incorporate some of the lime into the soil profile,” Ferrie says. “As we got soil pH somewhat tamed, the operator moved back to no-till, which he prefers. Since we were no longer incorporating lime, we had to reduce the amount applied and apply it more often.”

On the fertility side, everything involves the 4Rs—right product, right rate, right time and right place. “We have implemented variable-rate fertility, including applying some with the planter and sidedressing some of the nitrogen,” Ferrie notes.

Restoring soil health is complicated because the physical, chemical and biological aspects are interrelated. For example, the acid soil required high rates of lime, but you can’t add lime without tying up some phosphorus, Ferrie says. “Much of nutrient variability is controlled by soil microorganisms, the biological aspect of soil health.”

Shooting the slow rabbits of compaction and acidity produced quick results. The corn yield on Farm B’s silty clay loam rose from an average of 130 bu. per acre between 2008 and 2010 to 225 bu. in 2013 and 215 bu. in 2015. (The farm is in a corn/soybean rotation.) On its silt loam, yield increased from 123 bu. per acre from 2008 through 2010 to 215 bu. in 2015. The yield improvement was enough to make the farm profitable.

However, Farm B’s corn yield still lags 20 bu. to 30 bu. per acre behind Farm A.

Now comes the hard part: continuing to improve the chemical and biological aspects of Farm B’s soil health. “Because the soil was acid for so long, and subjected to too much tillage, much of Farm B’s soil structure has been destroyed,” Ferrie says. “We can’t fix structure with a single treatment—although the lime we’ve applied helped because the calcium flocculates clay particles (while the carbonate corrects acidity).”

Poor structure causes soil particles to run together and seal. That leads to erosion and surface crusting, which causes stand problems.

“While corn’s grassy roots might help build soil structure, the soybeans in Farm B’s rotation don’t help much,” Ferrie says. “We realized we had to add wheat or a grass cover crop to the rotation for continued improvement.”

The farmer chose a grass cover crop. Flying annual ryegrass seed into soybeans in 2014 sounded promising; but, for reasons not fully understood, the cover crop failed to establish.

In fall 2015, the farmer harvested some of the corn early (4% more moisture than the rest of the field) and drilled cereal rye into the stalks. “The timely seeding produced a good stand,” Ferrie says. In spring 2016, they no-tilled soybeans into the cereal rye.

In the more productive silty clay loam, the cover crop had no effect on yield. But in the less productive silt loam soil, in two locations within the field, there was an impact. In the first location, the cover cropped portion yielded 58 bu. per acre and the no-cover portion yielded 56 bu. In the second location, the cover cropped strip produced 55 bu. per acre, compared with 54.6 bu. without a cover crop.

Unlike a previous attempt at aerial seeding into soybeans, drilling a cover crop into corn stalks produced a good stand and had a small but measurable impact on soil heath.

Attempting to explain the yield effect, Ferrie ran several soil health tests. The results for the water-soluble (ortho) phosphorus and aggregate stability tests provided a clue.

“Water-soluble phosphorus is a pretty good indicator of biological health,” Ferrie says. “The increase from 1 ppm to 2 ppm at the first location is significant.”

Aggregate stability also improved under the cover crop. But Cornell University’s Comprehensive Assessment of Soil Health scores both areas under 20, on a scale of 100, which is considered very low. In contrast, Farm A’s health was rated 80. (See table below.)

“Although the improvement in aggregate stability was small, the score did move in the right direction,” Ferrie says. “Eventually, improvements in aggregate stability should result in improved water infiltration, and we’ll see improvement elsewhere, such as in the soil’s carbon/nitrogen ratio.”

The 2016 yield increase was not enough to pay for the cost of the cover crop (drying the early harvested corn, planting the cover crop and terminating it in the spring), Ferrie notes. “But at least it wasn’t a yield drag,” he adds.

A cereal rye cover crop was seeded in fall 2016. This spring, the operator will strip-till corn into the cover crop.

“We hope to keep the ball rolling, in terms of soil health improvement,” Ferrie says. “This past year’s results were encouraging but also disheartening because soil health is not improving as fast as I had hoped. Still, we proved we could make the farm profitable in just a few years.”

Despite boosting pH and fertility and removing dense layers on Farm B, the soil-test phosphorus readings, water-soluble phosphorus and aggregate stability percents and ratings are still much higher on Farm A, which suggests why the average soybean yield on Farm A is 7 bu. more per acre than Farm B.

Building on the Systems Approach, the Soil Health series details the chemical, physical and biological components of soil and how to give your crop a fighting chance. To learn more about this multiyear effort to nurture sick soil back to health, visit www.FarmJournal.com/soil_health

A Farming and Food Company Fit

Fri, 13 Nov 2020 06:02:05 GMT

Sustainability demands from major food companies are on the rise. Why? There is a growing recognition that sustainability isn’t a feel-good proposition and as food-related businesses delve into the supply chain, sustainability makes for good market sense—from the perspective of the farmer and the major company.

When Wal-Mart and other businesses in the food supply chain began focusing on sustainable farming practices, United Suppliers recognized opportunity. United Suppliers, a cooperative of more than 600 locally-owned and controlled agricultural retailers across the U.S., sought out the Environmental Defense Fund (EDF) for help to develop a platform focused on fertilizer optimization and soil conservation as well as good business sense for their agriculture customer base.

The fruit of their collaboration was SUSTAIN, a platform designed to benefit farmers and retailers while still addressing consumer concerns. “The end-consumer in agriculture is certainly not the grower; it’s the person buying food from grocery shelves. Consumers are demanding to know where food came from and how it affected the environment,” says Matt Carstens, United Suppliers vice president. “If we can meet that demand and still increase bushels and profitability, why wouldn’t we do it? SUSTAIN does precisely that: increases bushels, boosts profitability and addresses consumer needs.”

SUSTAIN helps farmers and retailers address three agronomic pillars (two that are highly active and a third remains in development): nutrient management, conservation of soil and water, and green fertilizer. Currently, SUSTAIN is pushing nutrient management and tackling nitrogen—and phosphate, to a lesser degree.

“Des Moines Waterworks, Lake Erie, the Gulf or Chesapeake Bay—these spots are giving agriculture a black eye and need to be addressed,” Carstens says. “We have to dig deep to get answers for nitrogen and phosphate management, and that’s part of why we came up with SUSTAIN.”

United Suppliers has made a commitment to have 10 million acres using best management practices in the SUSTAIN platform by 2020. The greatest portion of acreage will be in the Corn Belt, but it will include farmland coast-to-coast. The focus of SUSTAIN is to improve efficiency in ways that reduce nutrient loss in the soil, yet still maintains or even improves yields. Maximizing applied nutrients, reducing waste and preserving soil is a simple recipe for long-term economics.

In addition, SUSTAIN bolsters the trust and confidence of buyers and customers, notes Suzy Friedman, sustainable ag director, EDF. “It’s important to have a program like SUSTAIN helping farmers with innovative technology that also helps them document how they manage their operation,” she says. “Consumer concerns are coming at a fast pace, and sustainability is playing a significant role in how food companies make decisions.”

SUSTAIN addresses risk issues in an economical manner and offers consumers and food companies the information to know the sustainability footprint of a crop, Friedman says. “Retailers and growers participating in a program like SUSTAIN are in a better position with food companies that want to buy their crops,” she adds.

United Suppliers has a footprint across millions of acres and has positioned itself at the spearhead of sustainability measures—ahead of mandates that might be inevitable.

“I know this about fertilizer regulations: Things are going to change. I don’t know which will be first, food companies wanting something different or mandated government regulations, but one of those or both will bring change,” Carstens says. “United Suppliers and our retailers owe answers to growers. Whoever can guide those growers first will have more victories instead of waiting on mandated regulations to come down the pipe.”

Give Your Soil a Physical Exam

Fri, 13 Nov 2020 06:05:06 GMT

New tools and tests provide benchmarks to measure progress as you improve the health of your soil

It’s a good idea to pay a visit to your doctor every year—even if you’re feeling fine. A complete physical exam can give you the piece of mind to keep doing what you’re doing, or it could uncover areas of concern.

Soil is no different. “By evaluating the health of soil, we can get an idea of what’s good; what’s bad; learn where to start making improvements; and set benchmarks to measure progress,” explains Farm Journal Field Agronomist Ken Ferrie. “The process can tell you whether a piece of land you’re thinking about renting or purchasing will be a sound investment.”

There’s no time like the present to add a soil physical exam to your arsenal of management tools. “The sicker soil gets, the harder it is to bring it back to health,” Ferrie says. “New tools and laboratories offering soil quality analysis enable us to give soil a physical exam.”

You can’t expect all soils to attain the same level of health, Ferrie points out. “That would be like expecting an 83-year-old person to perform like a 17-year-old,” he says. “When you
understand your soil, you can make the most of what you have.”

A penetrometer measures soil resistance to penetration in pounds per square inch.

What to assess. A soil health evaluation involves assessing chemical, biological and physical aspects. You’re already familiar with the chemical aspect, which is your soil test. The biological aspect includes soil microorganisms that break down old crop residue and make nutrients available to plants.

Physical aspects include soil texture, aggregate stability, available water capacity, surface and subsurface hardness and infiltration rate. Texture and aggregate stability are key factors
that influence the other three traits.

“Soil texture—the amount of sand, silt and clay particles—affects nutrient- and water-holding capacity,” Ferrie says. “Farmers know water percolates easily into sand because of its large particles and pore spaces, but it tends to move right on through. It’s harder for water to infiltrate into a silt loam soil, but it tends to stay there after it enters. So the silt loam has more water-holding capacity.”

Think of aggregate stability as how well the soil maintains a crumb-like structure, in which sand, silt and clay particles are held together by organic matter and glues given off by mycorrhizal fungi.

“A healthy, crumb-like structure provides a stable structure for infiltrating and storing water,” says Robert Schindelbeck, Cornell University soil scientist. “The large macropores
between crumbs allow for rapid water intake and air exchange.”

A crumb-like structure allows better water infiltration, and downward and upward movement through the soil profile (via capillary action). “If we destroy that crumb-like structure (with abrasive tillage, for example), the soil surface will seal up, and water will run off,” Ferrie continues. “The surface will crust over and plants will have a tough time emerging.”

How to test. You can determine the percentage of sand, silt or clay by squeezing moist soil in your hand and trying to make a ribbon. “If it won’t make a ribbon, it’s sand,” Ferrie says. “How long a ribbon you can make determines whether it is silt loam, clay loam or some other texture.”

USDA’s Natural Resources Conservation Service (NRCS) offers an online soil survey to help determine soil texture. You can also have it analyzed in a commercial laboratory.

“The online soil survey is an excellent resource,” Ferrie says. “Just choose your state and location, and it will tell you your soil types. From that, you can figure out the physical properties, such as organic matter content, bulk density, percent sand, silt, clay and water-holding capacity.”

Using GPS technology, an app called SoilWeb lets you stand in a field and pull up information about the field’s soil type and associated properties.

Aggregate stability can be determined by a lab, or you can figure it out yourself in the field using a slake test or a rainfall simulator, such as the Cornell University Sprinkle Infiltrometer.

“Degraded soil melts into a gooey mess after water is applied,” Schindelbeck says. “This can dry into a sealed surface crust. Well-aggregated, healthy soils have more crumbs, which retain
their structure and functionality after water is applied.”

To measure soil hardness, or compaction, you or your consultant will need to go to the field with a soil penetrometer. “Measurements must be taken when the soil moisture is at field capacity because dry soil might show resistance without being compacted,” Ferrie says. “Look for resistance above 300 psi because that’s the amount of hardness that roots have difficulty penetrating.”

There are an array of soil penetrometers on the market, with varying degrees of sophistication.

A logging penetrometer made by Spectrum Technologies measures resistance for every inch of soil. Connected to a GPS unit, it creates a map that identifies density layers in the field. Several years later, the farmer can return to the same spot to see if he has made progress in removing dense layers.

A simple infiltration rate test involves driving a 6" ring into the soil, pouring in a known volume of water and recording how long it takes to soak in the ground.

You can also measure the amount of organic matter in soil by comparing it to a simple color chart—but Ferrie recommends a laboratory analysis for repeatable results. “You need a laboratory to measure the amount of active carbon,” he says. “This is the fraction of organic matter that breaks down fastest and makes nutrients available for plants.”

“Different labs may use different organic matter tests,” points out consultant Dan Towery of Ag Conservation Solutions, West Lafayette, Ind. “It’s important to use the same lab each time, for repeatable results. Sampling depth also is important. Soil within 2" of the surface will show changes in organic matter content much faster than soil at 7".”

Another important component of soil health is mineralizable nitrogen. That is ammonium nitrogen, a form that can be used by plants and microbes, which might be provided by soil organic matter during the growing season. “If you know the soil’s potential to mineralize nitrogen, temperature and moisture conditions during the growing season, it will give you an indication of how much ammonium nitrogen will become available,” Ferrie says. “That will help you decide whether to make a late-season application of nitrogen fertilizer.”

Mineralizable nitrogen can be measured using the Illinois Soil Nitrogen Test or the Cornell University Mineralizable Nitrogen Test.

Take a deep breath. Ultimately, soil health boils down to the health of soil organisms, Ferrie says—healthy soil contains more life. “It’s no exaggeration to say the “livestock” in your soil are as important as the livestock in your feedlot or dairy, and just as sensitive to their environment,” Ferrie says.

“An experienced agronomist actually can estimate the amount of life in soil by smelling it,” Ferrie notes. “It’s the scent you detect when soil is tilled. But this is subjective and difficult to document. So you need to run a soil respiration test and establish a numerical value that you can work with.”

Because microbial organisms breathe (sort of like humans), the soil respiration test reflects how many creatures are present, doing their jobs by decomposing plant residue and releasing nutrients for your crop.

The necessary equipment to measure soil respiration is included in some commercially available soil health kits. “Results will vary, depending on soil temperature and moisture levels,” Towery adds.

“The soil respiration test can be done in the field or in a lab,” Ferrie says. “For repeatability of results, always use the same type of test.”

On the road to better health. Studying your soil health analysis report along with your own yield zone map will show you where to start making improvements, Ferrie says.

Like every aspect of management, soil health requires a long-term strategy. “Take your soil samples and measurements in the spring, when soil moisture is close to capacity,” Ferrie advises. “Record locations using GPS, so you can return every three to six years and measure your progress.”

Some aspects of improved soil health—such as balancing nutrients and pH, removing compaction layers (and keeping them out), installing drainage to manage the water table and applying manure to increase organic matter—probably will boost yield and profitability quicker. Other improvements will take longer.

“Soil health is somewhat like human health,” Ferrie says. “The immediate consequences of being overweight and out of shape may not be a big deal when you’re young. But they can shorten your life, or reduce the quality of your life, many years later.”

“Improving soil health takes time, maybe several years,” Towery says. “Soil improvements you make now may or may not show an immediate benefit to your bottom line. Over time, they will result in a farming system that is profitable and sustainable for you, your kids and your grandkids.”

Soil Health Tests and Tools

The following four tests can analyze the state of your soil’s health. Most of the tools are included in commercially manufactured test kits.

In many cases, the tests can also be done by commercial laboratories. When tests can be done both ways, it’s a good idea to compare the results of both to make sure they are similar.

Soil hardness, or compaction, can be measured with a penetrometer. An Internet search will reveal several penetrometer manufacturers.

Soil respiration is measured with carbon dioxide meters or infiltration rings and Draeger tubes. In the latter technique, air is drawn through the Draeger tube and comes in contact with carbon dioxide-sensitive paper. The test measures the carbon dioxide given off by the microorganisms as they breathe.

Sprinkle Infiltrometer With Accessory Kit

The Cornell University Sprinkle Infiltrometer simulates rainfall onto the soil surface. Apply a given amount of rainfall, and measure how much soil falls through a screen. The more soil remaining on the screen, the better the crumb-like structure and the healthier the soil. You can also use an accessory kit with the Sprinkle Infiltrometer to measure the infiltration rate of water. Drive a ring equipped with a hose that captures runoff into the ground. Use the Infiltrometer to apply a given number of inches of water per hour. Subtract what runs off from what was applied to get the infiltration rate for a given period of time. Or, you can simply drive the ring into the ground and record how long it takes for each inch of water to soak into the soil.

Slake Test

“The slake test involves scraping soil off the surface, dropping it on a screen inside a cylinder and immersing the cylinder in water several times,” explains Farm Journal Field Agronomist Ken Ferrie. “If the soil is poorly aggregated, the onrush of water as you immerse the cylinder will blow the structure apart. Then smaller silt and clay particles will fall through the screen.” The cylinder on the left in the photo shows properly aggregated soil, and the one on the right shows poorly aggregated soil.

Air Dry Clods

One way to evaluate soil structure is to air dry clods from the same soil type but with different management systems in a jar of water, says Dan Towery of Ag Conservation Solutions, West Lafayette, Ind. With healthy, crumb-like structure (right), soil particles will hold together, bonded by organic matter and by glues produced by mychorrizal fungi, which are found around plant roots. With poor structure (left), the soil falls apart, or “melts away” when immersed in water.

Cornell University Takes Lead on Soil Health

Soil health is on its way to becoming a new buzzword in agriculture, and Cornell University is leading the charge.

The Cornell University Soil Health Team was formed in 2001. The primary goal of the soil and plant researchers was to learn why plants perform poorly in degraded soil conditions, explains Cornell University soil scientist Robert Schindelbeck.

“They concluded soil degradation had reduced the functioning of multiple soil processes,” Schindelbeck says. “They realized that soil physical and biological processes, which were not represented in standard soil nutrient analyses, needed to be routinely evaluated.”

The researchers set out to develop rapid, reliable and low-cost techniques to measure indicators of essential soil processes. Their efforts resulted in a soil health test that identifies constraints on the functions of healthy soil.

The university’s soil health testing service assigns a numerical value to four physical, four biological and four chemical components of soil. The color coded Cornell Soil Health Report report flags a grower’s attention to components that are constraining soil health and crop yield.

“I’m not aware of any other soil health test that provides the holistic assessment of soil constraints that ours does,” Schindelbeck says.

The university’s Soil Health website ( http://soilhealth.cals.cornell.edu ) describes the test and provides sampling and shipping instructions. A downloadable Soil Health Manual provides more information about the tests. There are links to management strategies farmers can consider to address soil health constraints. For farmers who wish to conduct their own tests of aggregate stability and infiltration, the university offers the Sprinkle Infiltrometer.

You can e-mail Darrell Smith at dsmith@farmjournal.com .

A Tale of Two Soils

Fri, 13 Nov 2020 05:59:23 GMT

On-farm tests help restore healthy soil characteristics

Imagine two farms less than a mile apart with the same silty clay loam and silt loam soil composition. During the past three years, corn yields on Farm A have averaged 200 bu. per acre on the silty clay loam soil and 187 bu. per acre on the silt loam. Farm B, on the other hand, has averaged only 130 bu. per acre on its silty clay loam portion and 123 bu. per acre on its silt loam.

The farmers of the two tracts use similar practices—no-till and a mostly corn/soybean rotation. The primary difference is that Farm A has been no-tilled for 30 years, and Farm B for only two years. Prior to that, it was farmed using horizontal tillage.

The massive structure of Farm B’s unhealthy soil shows why water fails to infiltrate and crop roots don’t penetrate.

Leaves, husks and silks were still evident on Farm B two years after a corn crop. Their presence indicates an absence of soil organisms, which indicates poor soil.

Perhaps you’ve seen similar yield differences in your own fields and wondered why one area yields more corn than another. Modern testing tools can help you pinpoint the culprit. On Farm B, the lower yields can be linked to poor soil health.

Farm A and Farm B are real. Farm Journal Field Agronomist Ken Ferrie has been working with Farm B for four years, helping the farmer restore soil health in order to boost yields.

In the beginning, Ferrie used soil pits and visual observation to evaluate soil health. But now, simple on-farm tests let him and any farm operator give the soil a “physical exam.” The tests provide numerical soil health ratings, which serve as benchmarks for evaluating soil health improvements.

Ferrie gave both farms a physical exam this past spring. “Because of the difference in soil health, the best soil on Farm B still can’t yield as well as the poorest soil on Farm A,” he says.

“Improving soil health means sustaining productivity and profitability,” Ferrie explains. “It requires a systems approach because healthy soil involves many components. The components fall into three categories—physical, chemical and biological.

“In some cases, it might be possible to fix physical and chemical problems fairly quickly. Often, improvements take many years, especially when the biological component is involved. Even so, the 70-bu. yield difference between the two farms shows that improving soil health is worth the effort.”

A physical exam—just like the one your doctor gives you—begins by assessing the farm’s appearance. Even after four years of effort on Farm B, the visual differences were still striking.

“In spring 2012, despite some heavy rains, all of the old crop residue remained in place on Farm A, which even has some slopes.” Ferrie describes. “On Farm B, with much less slope, the old crop residue and the soil eroded away, carried off by water.”

A glance at the soil surface revealed part of the reason why water is infiltrating into the soil on Farm A but running off the surface on Farm B. There were thousands of night crawler burrows visible beneath the residue on Farm A but almost none on Farm B. “Among the benefits of night crawlers, their burrows allow water to infiltrate the soil,” Ferrie says. “They also help remove excess water, functioning like part of your drainage system.”

Part of the reason water couldn’t infiltrate the soil of Farm B was its degraded structure. Digging revealed impenetrable blocks of soil, compared with Farm A’s healthy crumb-like soil structure containing macropores for water and air.

Another symptom of poor health, visible on the surface of Farm B, was two years’ worth of old crop residue. Not only was 2012’s soybean residue present, but even the fine leaves, husks and silks, which should be among the first and easiest to decompose, were present from a corn crop grown two years ago.

“That indicates a biological problem because residue is decomposed by soil organisms,” Ferrie says. “The absence of night crawlers is one of the indicators that confirms it.”

Simple tests conducted by Ferrie’s assistant, Thomas Zerebny, placed the degree of Farm B’s problems on a numerical scale. He used equipment from a Gempler’s Soil Test Kit.

A slake test, which involves immersing surface soil in water and seeing whether it holds its structure, produced scores of 2.7 for Farm B’s silt loam and 5.0 for its silty clay loam, compared to 3.7 and 5.7, respectively, for the same two soils on Farm A. The higher the score, the healthier the soil structure and the less chance it will seal over during a rainstorm and restrict infiltration.

Zerebny used a rainfall simulator, available from Cornell University’s Soil Health website, to analyze aggregate stability or structure in the top 6" of soil. It revealed that structural problems on Farm B are not limited to the surface of the soil.

The rainfall simulator also documented the difference in water infiltration caused by poor soil structure. Farm A’s silty clay loam took in 8.6" of water per hour, compared with 2.8" per hour for Farm B’s silty clay loam. Farm A’s silt loam soil took in 3.6" of water per hour, compared with only ½" per hour on Farm B’s silt loam.

Gas detection tubes (also called Draeger tubes) were used to measure the amount of carbon dioxide being released by soil organisms. The beneficial organisms breathe oxygen and release carbon dioxide, just like people, which is why soil needs pore spaces—to provide oxygen for the microbes. The amount of carbon dioxide is an indication of microbial activity. The results showed about 50% more microbial activity in the healthy soils of Farm A.

Health quest. Ferrie’s examination of the results showed that the operator of Farm B needs to continue to focus on physical and chemical issues to improve soil health. The operator is using vertical tillage tools to remove hardpans, compaction and tillage layers.

Vertical tillage and liming work together to fix structural problems. “When a field gets extremely acid, acidity destroys structure and stops water infiltration,” Ferrie says. “When we apply lime, we are attempting to flush out the acidity. If we have poor infiltration, we can’t get water into the soil to make the lime work.

“Applying lime, (calcium carbonate) helps fix structural problems and keeps pH in the 6.3 to 6.5 range, which is optimal for soil microbial activity. The carbonate bonds with hydrogen (acidity) and helps flush it out of the soil.”

Calcium improves structure by helping to flocculate clay particles. Flocculation means the particles are held together, yet somewhat apart. “It’s the first step in creating better aggregate stability or structure,” Ferrie says. “A healthy crumb-like structure lets water infiltrate and contains macropores. The macropores hold air and usable water, which is accessible to crop roots.

“Together, vertical tillage and lime applications will let us gradually build up soil pH from the 5.0 range, where it was when the operator took over the farm,” Ferrie says. “Eventually, after soil health improves, he will no-till Farm B just like his other farms.”

Cover crops are also part of Farm B’s recovery plan. Deep rooting crops can penetrate some hardpans and compacted layers. The roots of grass crops aid in the process of producing a glue-like substance that helps bind soil particles together.

In fall 2012, the farmer’s initial attempt to aerial seed a cover crop of annual ryegrass and tillage radishes failed, apparently because of environmental conditions. That illustrates how resuscitating abused soil takes a long time—probably decades for Farm B.

Regardless, gradual improvements in soil health will lead to gradual improvements in yield, Ferrie concludes. They will also lead to healthier water sources because of fewer nutrients washing away and a more sustainable farm for future generations.

Building on the Systems Approach, the Soil Health series will detail the chemical, physical and biological components of soil and how to give your crop a fighting chance. www.FarmJournal.com/soil_health

You can e-mail Darrell Smith at dsmith@farmjournal.com .

When a Soil Test Lies

Fri, 13 Nov 2020 05:56:23 GMT

Crop consultant Del Glanzer is known for pestering his clients about proper soil testing. He is convinced that at least 25% of soil fertility issues are related to poor soil sampling, which leads to misguided test results—and flawed execution.

“Many farmers are lax in their soil sampling, so they end up with the wrong analysis and bad decisions,” explains Glanzer, who is based in Alexandria, Minn., and works with clients across the Midwest. “With the cost of fertilizer today, you can’t afford to be fooled.”

The best rule of thumb in soil sampling is that the plant and the soil sample have to match, Glanzer says. He gives the example of a client’s 40-acre field with flat, sandy soils. The client took a composite soil sample in the fall right after harvest that showed adequate fertility levels, including magnesium. Yet, when the corn reached 8" tall, at least three-fourths of the field showed magnesium deficiency in the form of striping on leaves.

“No matter what the soil test shows, the plant is the true test. And the plants said three-quarters of the field did not have adequate magnesium,” Glanzer explains.
In that case, Glanzer and the farmer began sampling both in the fall and late spring. They further divided the field to sample the good and poor spots separately and eventually eliminated the magnesium deficiency problems.

As a crop consultant for more than 30 years, Glanzer has witnessed (and made) all sorts of soil sampling missteps. He and his associate Jared Anez of Anez Consulting in Willmar, Minn., have developed a list of key factors that can derail soil test results. Here are their top five:

1. Sampling in compacted soil.
When farmers sample in compacted soil, they don’t realize that compaction restricts the roots’ water and air movement, so yields are undermined. “The result is the soil test shows good fertility levels, but with the hard layers the plant can’t get the fertility it needs,” Glanzer explains. To help identify compaction problems, he often takes soil samples by hand so he can feel if the soil is tight and compacted. If a problem is present, he encourages the client to deal with it before planting.

2. Failure to adjust soil sampling to growing field size.
Be careful of blending parcels together as fields enlarge and machines get bigger. Old fence lines need to be respected. For instance, a farmer who purchases two 40-acre fields that were once farmed separately needs to ask questions about the land’s history, including fertilizer use, manure spreading problems and other factors that could impact the fields’ fertility. “We suggest you sample newly purchased fields separately the first year and don’t combine them until you are positive the soil test is close,” Glanzer says.

3. Forgetting a field’s production history.
The life of the field has a huge impact on soil test results, Glanzer says. Knowing the field’s disease, insect and weed history can impact decisions for the growing season. Yield maps and yield histories can point out the differences, but watch for other signals, as well. For example, certain weeds can point to other problems. Yellow nutsedge, for instance, thrives in soils with poor drainage.

4. Sampling where fertilizer was spread unevenly.
Manure spread on only a portion of the field can greatly skew a soil test, Glanzer says. If you happen to sample where manure was accidentally dumped at one time, that will throw a soil test off for years.

5. Going with a cheap test.
Sometimes you need more than just a soil test for phosphorus, potassium and pH, Anez says. This is especially true for soils where pH is an issue. “One of the downsides of grid sampling is that the cost gets so high farmers start to eliminate things to test for,” Anez says. “Even if you don’t order a full sample every time, you should try to test for sulfur and trace elements when you can.”

One of Glanzer’s favorite sayings is: If you don’t know where you’re going, then it’s hard to get there. That is certainly true with crop yields and fertility management. All farmers, he says, whether they are crop or livestock producers, need to be developing a short-term and long-term nutrient management plan.

“This gets back to the point of having an end goal in place,” Glanzer says. “The producers who keep their eye on their goal will end up saving money on fertilizer this year.”

Spring Nitrate Test Tips

The large amount of rain and potential leaching last year spurred many producers to use a late-spring soil nitrate test to estimate additional nitrogen (N) fertilizer to be sidedressed. The test is often called a presidedress nitrogen test (PSNT).

The test helps estimate the likelihood of yield response to any additional fertilizer when soil nitrate concentrations found in the surface are below the critical nitrate range, says Peter Kyveryga, senior research associate with the Iowa Soybean Association’s On-Farm Network.

Optimal range. A range of 20 to 25 parts per million of nitrate-N is considered optimal. Lower the optimal range, however, when rainfall in May is more than 4" and when the test is used for soils receiving manure and anhydrous ammonia. The test should be done when the corn is 6" to 12" tall.

It is a good idea to use the late-spring soil nitrate test if all or the majority of N fertilizer was applied before planting and there is concern about losses, Kyveryga says. However, just as with a traditional soil test, bad sampling for a PSNT can lead to wrong results. The largest errors often occur because the nitrate concentration of the soil sample does not represent the nitrate concentration of the field, he says.

“The most difficult fields to sample for this test are the ones where nitrogen was applied in a band as anhydrous ammonia or injected swine manure,” Kyveryga says. Also, when fields are saturated or flooded, the test can show inconsistent results, he adds.

The best way to sample fields with banded N is to collect three sets of eight cores, positioned at various distances between two corn rows. With this method, the person doing the sampling moves in a random pattern within the test area. Each time a core is collected, its exact position is selected relative to the two nearest corn rows: The first core is collected in a row; the second is collected one-eighth of the distance between any two rows after moving to another part of the test area; and the third is one-quarter of the distance between two rows after moving to another part of the test area.

The process continues until the eighth core is collected 7⁄8 of the distance between any two corn rows. Soil from all cores should be crushed and thoroughly mixed before a subsample is sent for analysis.

The late-spring soil nitrate test is a diagnostic tool that can reduce some uncertainty in N management, but it cannot predict the magnitude of yield response in individual fields, Kyveryga cautions. “Understanding what this soil test can do and cannot do is crucial when using this test during the growing season,” he adds. For more information, visit www.isafarmnet.com .

You can e-mail Jeanne Bernick at jbernick@farmjournal.com .

Banking on Biofuels

Fri, 13 Nov 2020 05:58:44 GMT

Development ramps up for cellulosic ethanol

Athick mat of corn stubble stretches across Jeff Taylor’s fields after harvest each fall like a dense, golden carpet. The sturdy stalks, developed through years of focused breeding efforts, don’t completely decompose during the winter and interfere with spring planting. Taylor thinks he might finally have a solution. He believes a new cellulosic ethanol plant under construction a few miles south of his farm will help him turn the tough cornstalks into cash.

“All of a sudden, farmers have a market for a product that wasn’t even a commodity two or three years ago,” says Taylor, who lives near Nevada, Iowa, the site of a cellulosic ethanol plant DuPont will complete in 2014.

The $200 million plant will use cornstalks and cobs, called stover, to produce 30 million gallons of biofuel annually. The site was selected, in part, because of synergies company officials hope to gain with Lincolnway Energy LLC, whose corn ethanol plant sits on an adjacent plot.

The new plant will require 375,000 dry tons of stover each year to meet the company’s annual biofuel output goal, reports James Collins, president of DuPont Industrial Biosciences. That will require DuPont to contract with up to 500 corn growers within a 30-mile radius of Nevada.

“This is the first of 100 plants we expect to build over the next 20 years,” Collins says, noting that the plants will be built in heavy corn production areas.

Harvesting stover offers farmers such as Jeff Taylor of Nevada, Iowa, agronomic and financial payoffs.

Friendly fuel. Cellulosic ethanol is a renewable energy source that does not contribute to the food-versus-fuel controversy like corn ethanol. Cellulosic ethanol is produced from nonfood sources, ranging from corn stover to industrial wastes, such as paper sludge.

“The production process delivers a clean-burning, high-octane fuel that is the same as ethanol made from corn,” says Dan Burden, program coordinator for the national Agricultural Marketing Resource Center.

More than 20 companies are currently exploring opportunities with the biofuel. One of them, Abengoa Bioenergy, is constructing a cellulosic ethanol biorefinery in Hutchinson, Kan. It will require 65 full-time employees upon completion in 2014.

Poet, based in Sioux Falls, S.D., is building a cellulosic ethanol plant near Emmetsburg, Iowa, via a joint venture with Royal DSM, a $12 billion Dutch-based company.

Poet plans to co-locate cellulosic production with its 27 corn ethanol plants and produce up to 1 billion gallons of cellulosic ethanol annually, reports Wade Robey, senior vice president for technology.

Some companies plan to retrofit existing ethanol plants to produce biofuels and other biochemicals. Gevo, Inc., based in Englewood, Colo., is producing isobutanol from cellulosic, nonfood biomass, says Christopher Ryan, president, chief operating and chief technology officer. Isobutanol is a naturally occurring four-carbon alcohol with applications in chemical and fuel markets.

The federal government has set a goal of producing 16 billion gallons of cellulosic ethanol annually during the next 10 years.

Development challenges in the past decade severely stunted the enthusiasm that companies and farmers initially had for cellulosic ethanol.

“I believe a lot of us have been skeptical about it,” says Jim Hill, who farms with sons Ryan and Adam near Ellsworth, Iowa. “When you take my stalks away, you’re taking some of my nutrients for next year’s crop.”

Taylor says his fears were put to rest once Iowa State University got involved in the DuPont project. A team led by Matt Darr, a professor in the Department of Agricultural and Biosystems Engineering, sampled each bale removed from Taylor’s fields to evaluate nutrient levels and how their removal affected his soils.

“Those projections tell me how much I need to be compensated to replace the fertility value on that field,” Taylor says.

Research by Darr and a colleague, Keith Webster, indicates that harvesting stover can increase net profits for continuous corn production in Iowa to about $45 an acre.

Taylor and Hill say agronomic payoffs are the primary benefits.

“Residue contributes to pathogens and overwintering insects that can impact the next crop, so getting rid of some of that stover is good,” Hill notes.

Taylor agrees: “Removing a small amount of stover saves a tillage pass, and I get warmer soils faster in the spring. I also get more consistent seeding depth and better crop emergence,” he says.

Most companies take no more than 50% of the available stover from a corn field in any given year.

One pass or two? Companies working to meet stover harvest requirements include AGCO, Case IH, Claas, Demco, John Deere and Vermeer. Most are evaluating some version of a
one- or two-pass harvest process. In the two-pass process, farmers harvest their own grain and the company collects the stover; in the one-pass process, the company harvests both the corn and stover. Hill and Taylor prefer the one-pass process as it eliminates the need to purchase equipment.

Taylor says that based on their experiences, he and his 82-year-old dad, Bob, believe stover harvest holds promise for corn growers.

“He remembers the Great Depression and Dust Bowl, so we said no twice before we said yes to trying this,” Taylor adds. “If you can convince someone from that era like my dad to remove stover from their fields, you know you’re on to something.”

You can e-mail Rhonda Brooks at rbrooks@farmjournal.com .

What Makes Healthy Soil?

Fri, 13 Nov 2020 05:58:44 GMT

Take the first step toward more stress- and drought-resistant soils by adopting the Systems Approach to soil management

Nearly 75 years ago, USDA soil scientist Charles E. Kellogg wrote: “Essentially, all life depends upon the soil.” Expressing a similar sentiment, President Franklin D. Roosevelt said: “The nation that destroys its soil destroys itself.”

Think about it: No matter how much management, labor and fertilizer you apply, and regardless of the quality of seed you plant, it’s the soil that underpins how much food and fiber you produce.

During the hard-hitting drought this past summer, it wasn’t uncommon for one field to vary from 170 bu. to 240 bu. per acre while a nearby field of the same soil type struggled to make 100 bu. Some fields yielded zero because they folded under stress.

Farm Journal Field Agronomist Ken Ferrie saw it, too. “Some of the low yield may have been due to planting date or hybrid selection,” he says. “But some of the difference was due to poor soil health.

“In adverse conditions, healthy soil will hang on longer,” Ferrie says. “But unhealthy soil may burn up before the crop gets started.

“Farmers have always looked at the individual components of soil health, such as fertility, tillage and water management. But to really improve soil, we have to look at all the components together, in a Systems Approach to soil management.”

Farm Journal’s new series of in-depth articles about soil health will help you do that.

The first step is defining your objective. “I like to define soil health as sustained productivity,” Ferrie says.

“But we could also call it ‘maintaining profit,’ not just for ourselves but for our kids and grandkids.”

Soils were not created equal in terms of yield capacity, Ferrie notes. “Soils differ in their ability to produce a crop,” he explains. “Your lightest soil, even in the best of health, may not keep up yieldwise with a darker soil in poor health. It’s like comparing a 17-year-old to an 80-year old. Eventhough both are healthy, the teenager is more athletic.

“Even if he’s overweight, the 17-year-old may still outrun and outjump a fit 80-year old. With soils, too, some are naturally more athletic. But by making all our soils as healthy as possible, we maximize each one’s productive capacity.”

Let’s start by describing unhealthy soil, the kind you want to—have to, if at all possible—improve. You know the symptoms: poor tilth (crusting and compaction, fields struggling to get a crop up); disease problems, especially seed rot and early pythium; poor infiltration (water runs off the unhealthy soil, while it soaks into the healthy soil—often in fields that are side by side); ponding, resulting from poor drainage; low water-holding capacity (soil dries out while healthier fields stay green); unbalanced fertility, caused by pH issues; and clay knobs where the topsoil has been eroded.

What soil health is. Now let’s examine the characteristics of healthy soil. With the first one, depth of topsoil, you are limited by what nature—and, in many cases, years of erosion—have provided. “But you can still maximize the health and productivity of whatever soil you have,” Ferrie says.

You already are managing fertility, striving for balanced nutrients and proper pH. If you haven’t been blessed with naturally well-drained soil, you probably have installed some drainage to remove high water tables before they damage a crop. Good drainage also lets you make field passes in a timely fashion, without causing compaction.

Healthy soil has sufficient waterholding capacity for its soil type to help crops survive dry seasons such as 2012 (which accounts for some of the yield differences we mentioned earlier).

You understand soil tilth and are trying to improve it because tilth affects water infiltration. But this aspect of soil health is a little trickier than balancing nutrients, Ferrie notes.

“Using tillage, we can eliminate sudden density changes, improve infiltration and increase usable water-holding capacity,” Ferrie says. “We can also decrease surface and subsurface hardness. However, doing the wrong tillage at the wrong time can destroy everything we’ve accomplished.”

Healthy soil contains strong and diverse microbial activity. “In a handful of soil, there are more microbes—bacteria, fungi and actinomycetes—than there are humans on the face of the Earth,” Ferrie points out.

The good things you do for your soil are actually aimed at supporting those microbial populations. “For example, we tend to think we are applying fertilizer to feed crop plants,” Ferrie says. “But those nutrients must be processed by microorganisms and then released to the plants.

“When we apply lime, we are applying it not for the corn crop, but for the microbes,” Ferrie adds. “Corn can live with a pH as low as 4.0. But soil microbes can’t.

“In fact,” Ferrie summarizes, “everything that we do to improve soil health is really aimed at building and maintaining this diverse population of soil microorganisms.”

Finally, healthy soil is free of toxins. That includes herbicide residues, allelopathic substances and acids.

The defining characteristic of healthy soil—the one that jumps out at you from the road or the combine monitor—is its ability to resist adverse weather events, such as drought.

“If you succeed at managing those factors, you’ll have healthy soil,” Ferrie says.

Chemical, physical and biological. One way to evaluate the management aspects of soil health is to think of them as chemical, physical and biological.

You already understand the chemical side. It’s the nutrient and pH analysis that you find on your soil test.

“Physical aspects like soil texture— the percentage of sand, silt and clay particles—make some soils more ‘athletic’ than others,” Ferrie says.

There’s a huge difference in the size of those particles. “Think of it like this,” Ferrie says. “If a sand particle is a 747 airliner, a silt particle is a Cessna and a clay particle is a hummingbird.”

Another physical aspect is aggregate stability. “Healthy soil has particles bound together, in a crumblike structure, or soil aggregate,” Ferrie says. “Different sized aggregates create macropores, which hold water that can be extracted and used by plants. Smaller pores, called micropores, also hold water, but it is bound tightly to soil particles and unavailable to plants.

“In healthy soil, if you immerse an aggregate in water, it will hold together. If the aggregate falls apart, sand remains in the upper layer, while silt and clay shift downward in the soil profile. This changes macropores into micropores, inhibiting water percolation,” Ferrie explains.

“So aggregate stability translates directly into available water-holding capacity—the amount of usable water your soil can hold above the water table,” he summarizes.

“For practical purposes, the waterholding capacity determines how heavy a population you can plant—something you must understand to use variable-rate technology.”

Another physical property of soil is penetration resistance. You can think of it as compaction or soil strength. When soil is free of compaction and dense layers, it is easier for crop roots to penetrate. It’s also easier for water to move upward, via capillary action.

The biological aspect is organic matter—the portion of soil that was once living plants or animals. That’s one of the things that makes soil microorganisms so important. They mineralize organic matter into nutrients that crop plants can use.

Soils with higher levels of organic matter are able to retain more nutrients. This is called cation exchange capacity (CEC) and is expressed as a numerical value.

“We’re looking for a balance of chemical, physical and biological aspects,” Ferrie says. “It’s possible to have high soil fertility levels due to manure applications but poor soil biology and physical health. An organic farmer could have great physical and biological properties in his soil but poor chemical health. For healthy soil, you must manage all three components.”

Each component—chemical, physical and biological—can be tested, providing benchmarks to measure your progress in improving soil health.

Make your soil healthier. When you understand the various aspects of soil health, you can start improving it.

Tackle the ea siest steps first. These include balancing fertility and pH levels and using vertical tillage to remove compacted layers, Ferrie says. Improve drainage if you and your landlords can afford the investment.

After that, the options get tougher. “Reducing tillage is beneficial,” Ferrie says, “but it may delay planting, especially in northern areas. No-till may be difficult in poorly drained soils. Some can’t be no-tilled until you improve structure. Changing tillage systems requires its own Systems Approach, from planting through harvest.”

“Diversified crop rotations are better for soil health, but they don’t fit many operations that have specialized in a few crops for efficiency,” he says. “For new crops to be practical, they require markets, storage capacity and often livestock.”

Cover crops, in conjunction with no-till, have the highest potential to improve soil health. “Cover crops can provide diversity for soil microbes; improve soil aggregation, water filtration and storage; suppress weeds; reduce soil erosion; and recycle crop nutrients so they won’t escape and pollute water sources,” Ferrie says.

“But just like adding new cash crops to your rotation, cover crops require knowledge and good management to be successful—so do your homework first. Decide what cover crop to plant, based on the cash crop that will follow it next spring.

“Decide now when you’re going to kill the cover crop next spring—and who will kill it, you or your retailer,” Ferrie says.

Determine whether you will have to pay a carbon penalty because of the increased residue created by the cover crop—and, if so, how you are going to pay it. Whether or not there’s a carbon penalty will depend on which cover crop you plant and which cash crop follows it.

Short growing seasons add to the challenge. “Planting a cover crop without fully understanding all these things is failing to apply the Systems Approach,” Ferrie says.

Short-term versus long-term. The conundrum with soil health is maintaining profit as you make improvements. “The most profitable farms may not be the healthiest, and the healthiest farms may not be the most profitable,” Ferrie says. “But when you find that balance, you’ll have a farm that is healthy, profitable and sustainable for your generation and generations to come. Those are the fields our kids and grandkids will farm in the future. Let’s leave them a legacy of healthy, sustainable soils.

“That’s the goal we have to keep in mind as we invest our time, money and effort in improving soil health. It will be worth the effort.”

We’ll tell you how to measure the health of your soils, and how to start improving them, in future installments of this series.

Fast Facts

Characteristics of Healthy Soil:

Deep topsoil, based on soil type
Balanced nutrients and proper pH
Good drainage
Usable water-holding capacity to withstand drought
Good soil tilth
Resistant to adverse events
Strong and diverse microbial populations
Free of toxins

Characteristics of Unhealthy Soil:

Poor tilth
Crusting
Compaction
Disease
Poor infiltration
Poor drainage
Low water-holding capacity
Unbalanced fertility