University of Illinois: Final Report

As prepared by Dr. Laura Gentry and Dr. Fred Below, and summarized by Mike Petersen – an executive report from the University of Illinois for crop year 2013 (CY13).


Stover accumulation has been shown to reduce corn grain yields in continuous corn production systems leading to suggestions that high corn prices, which result in more continuous corn production, will also could result in widespread implementation of stover removal practices. However, effects of stover removal on soil fertility requirements and soil organic matter levels is an on-going concern and must be considered when growers decide to remove stover from continuous corn fields. In this project, we (Fred Below, Laura Gentry and associates) assessed the effectiveness of stover removal for increasing corn yields in high-yielding and conventional environments as well as nutrient management consequences of stover removal. High yielding environments consisted of higher plant populations, increased nutrient fertilizer application, insect protection traits, and application of fungicides. Conventional environments consisted of more common planting populations, less intense fertilizer applications, no insect protection traits (a granular soil insecticide was applied at planting in both environments), and no fungicide application. Additionally, three residue management treatments (crop rotation, partial stover removal, and tillage) were applied at two levels (9th-year continuous corn vs. long-term corn-soybean rotation, stover retained vs. 50% stover removed, and conventional tillage vs. strip tillage) to assess their individual and combined effects on the input treatments (plant population, nutrients, traits, and fungicide) and corn yields. In this summary we are reporting the results from 2013. Click table to view larger:

2013 corn yield results

Yellow: Corn/Soybean rotation with all practices employed
Orange: Same, without P-K-S fertility added
Blue: Better hybrid taken out, standard hybrid selected


Strip tillage is a relatively new reduced tillage system in the Central Corn Belt that protects soil from erosion, retains plant-available water, maintains soil structure and retains soil organic matter, and allows banding of fertilizers for more efficient plant uptake.  Strip tillage can substantially reduce soil compaction associated with multiple seedbed field operations; this also represents cost savings as a result of eliminating fuel use, labor, and equipment wear.  These three agricultural management practices – crop rotation, residue management, and reduced tillage – were tested for their individual and cumulative effects on agricultural sustainability parameters and corn yields in combination with the omission treatment design previously employed to investigate high yield management factors for corn production.

(Above Executive Summary provided by Laura Gentry, PhD.)


Comments/Observations by Orthman Soil Science Agronomist, Michael Petersen:

As we observe and evaluate this data set that Gentry and Below studied several key points that come up before growers minds as they evaluate the validity of Strip-Tillage, rotational changes, hybrids, fertility programs even in a year like 2013 when the spring was wet and planting was delayed.  Please note in the supplied table the colored cells; yellow highlighted cells depict in the Corn-Soybean rotation portion of the Gentry-Below studies in the High Tech plots in which all practices are employed, incl: P-K-S etc fertilizer added precisely, high-sustainable N rates employed, best hybrids (with insect, herbicide resistant, day length, etc), higher seeding populations, and fungicides applied at premium time.  In orange cells the additional P-K-S etc fertility is subtracted.  In the blue cells the better hybrid selection is taken out and standard hybrid selected.  Much the same as what we have observed at the Orthman Research Farm near Lexington, Nebraska – precision tillage offers a slightly better yield advantage, which along with savings in fuel, time, and other costs – IMPROVES PROFIT MARGINS.

Lastly, in the last line of the table, precision tillage results in the averages Continuous Corn/Retained with Strip-Tillage compared to Conventional Tillage (second left column) an advantage leans to Strip-Till.  We are pleased that Dr. Gentry supplied us these data and will continue the studies in 2014 with the use of Strip-Tillage using the Orthman 1tRIPr and dry fertilizer application system by Valmar.

More roots = happier plants!

A New Look at How Strip-Tillage Gives an Advantage Due to Larger Root Length to Soil Volume – This Affects Plants to Tolerate Stress Better

by Michael Petersen, Lead Agronomist
For 8 years now we at Orthman have been honing our skills to better understand what happens with strip-tillage and corn rooting. How is this all happening so corn plants can tolerate heat and drought stress better?

Figure 1: A top-notch seedbed to plant into - Courtesy Greenfield Ag, Ohio

It is our agronomic opinion that we are first accomplishing with the Strip-till implement a "better seedbed" to establish an environment where the germinating plant can extend a longer and more profuse seedling root. We have seen this in corn, cotton, grain sorghum and soybeans with strip-till compared to conventional tillage and direct seeding. Our observations have been at 15 days after emergence (DAE) and 25 DAE with the monocots (corn and grain sorghum), and 25DAE with the dicots (soybeans and cotton). What are those factors? First, we are seeing warmer soils in the upper 4 inches (10cm) of the soil profile in the strip-till zone-- from 1 to 7 degrees Fahrenheit warmer. With cotton, grain sorghum and soybeans (which all germinate closer to 58 – 60° F), those few degrees of temperature are vital to good germination and stand establishment. I'm not saying it is not important for corn, but corn does tolerate a few degrees cooler. A critical point - the soil density for the seedling root in the zone that is strip-tilled is very conducive to root elongation and early lateral root development off the seedling root with Strip-Till. All of this early root development feeds the plant, gets the plant off on the right foot so to speak when the inevitable chill of May comes and then heat of the summer. We all know the wind will blow hard at some point in the first 25-30 days of growth after emergence. Having a well established root system will not only anchor the plant but help it sustain life. Secondly, as farmers are placing nutrients with more precision these days (which we highly recommend with the Orthman 1tRIPr) the roots are in direct contact with the nutrient source and will continue to thrive going into the critical stages of the life cycle. It is well known that crop roots are the dominant site (>98%) where nutrients are absorbed and taken into the plant for photosynthesis and carbohydrate storage – yield. This second pillar, “Precision placement of fertility” is talked about often here at Orthman as being vital to higher sustained yields. For instance in corn; near the time of 45 DAE the corn genetic road map has determined the number of kernel rows around the cob. Having a rich environment of nutrients (whether organic or inorganic) around the roots can influence the switches to be turned on across the gene map to expand from 12 to 14 to 16 to 18 or even 20 rows. More availability to the nutrients and roots accessing those products invigorates the plant to establish a larger ear, offering that multiplier effect. Having a larger root length density (RLD) which we will expand upon here shortly in this article is critical for the grower to reach higher yield potentials. The 3rd pillar of the Precision Tillage concept is having an optimal root zone to facilitate an environment for more water and nutrient uptake for the planted crop. This underground environment is unseen by most and really needs to be considered, whether you are a grower, fertilizer dealer, or even agronomist in the field. I have spent 40+ years digging to understand the “ways” of the soil system as a soil scientist and it is important that all understand this message. The physical distribution of roots in the soil profile is dominated and affected by several factors:
  1. Gravity
  2. Soil temperature
  3. Soil moisture
  4. Chemistry of the soil solution
  5. Soil density
  6. Crop root architecture [crop genetics]
Of those six, gravity, soil chemistry and the wet/dryness are not changeable without irrigation. Soil temperature in the spring can be altered slightly as mentioned earlier. Maintaining residues on the soil surface can help hold moisture, add to soil foodstuffs for microbes and critters in the soil as well as mycorrhizal fungi helping nearly all crops. Soil density is something tillage can alter (either for good or it can be detrimental). Crop rooting architecture is a given but can be facilitated to reach all of its potential with Strip-Tillage. Let us consider the root-zone from a Strip-Tillage perspective: first, early soil warm-up. Getting that germination started with good seed-to-soil contact, warmer for the early root system, right in the presence of readily available nutrients – like feeding a toddler on into the teen years when food is inhaled and kids shoot up. Feed them properly and they perform whether kids or corn and soybeans. For instance, proper nutrition and a soil environment is conducive to root expansion without limitations. By the time it is 75 days old, a corn plant can have a root system over 750 feet in total length and longer – precise placement of nutrients with Strip-Till is a big part of that success. We have actually measured over 1,326 feet of total root length under one corn variety that was strip-tilled in Eastern Colorado studies. Growers across the United States can tell you that amount of roots will be way bigger than they can imagine in a strip-till system, especially when we consider that rootworm pressure, nematodes, root rots, compaction, early water logging, and cold soils all take away from a crops root proliferation.

Figure 2: Robust corn root system at 25DAE with strip till

That brings us to how much of a root system is important to making the plant a “big crop”, especially in a year when rainfall is considerably limited? So think on this; Root Length Density (RLD) is defined as root length per unit volume of soil [cm root/cm3 soil]. If RLD averages above 0.35cm/cm3 below the 80cm (36 inches) depth, the corn plant will be able to pump water from depth to the upper portion of the root system and sustain life much longer than plants with lower RLD. When we can help promote an even larger RLD for the entire rooting profile with Strip-Tillage (such as measured in Nebraska and Colorado in 2013 over 3.95 cm/cm3 at two different study sites!), the concept is onto something! Those same studies show a full-width tillage rooting system of just 2.35 cm/cm3. It is our goal with Precision Tillage and placement of fertilizer products to encourage plants of corn to grow deeper, expand into more segments of the soil profile so to absorb more water and nutrients which in turn leads to better yields and dry matter. Other researchers have measured in natural rainfed agriculture root systems that had RLD’s of 0.7 to 1.25 cm/cm3. Here in at Orthman we have seen the value of establishing a strong and dynamic root system making yield differences every year at the Orthman Research Center near Lexington, Nebraska. Getting you an ideal seedbed, placing fertility in the root pathway and making sure you have an optimal root zone is what strip-till growers benefit from. M Do not hesitate to call or e-mail amy of us on the agronomy team . We want to be a resource for you, as strip-till is the fastest growing smart and sensible tillage method on the planet.

Winter time is the time for your planter tune-up!

Planting via the Precision Tillage System method at the Orthman Manufacturing Research Proving Grounds.

Here at Orthman Manufacturing, we know this time of the year is a great time to check out the planter and its functionality to get the seeds in the ground like you want come April. Read the one page article that has some thoughtful words on being a precision farmer.  Click on the following link (Orthman Planter) to read what Randy Haarberg says; Orthman_Planter article2014.

With Better Precise Fertility Placement in Strip-till, Can we enhance Plant health and avoid Poor Stalk Conditions?

Our Lead Agronomist, Mike Petersen has been up to or should we say getting down to it, finding more out about the issue of potassium (K) having a role in the issue across parts of the Corn belt of corn going down bad. His talks with other wise Agro’s across the U.S., delving into research, reading texts has come to him writing a two page article. Look it over. Click on the hyperlink (text in orange color) Better precise K and S fertility_StripTill and enjoy!

Numbers of Growers are expresing concern over fall stalk issues – Is K at the bottom of this?



Our lead Agronomist has been digging as usual but this time into research papers, talking with fellow agro’s, reading and then wrote this to offer some suggestions as to why we across segments of the Corn Belt are experiencing weak stalks in corn. Is it strip-till has been a question to us? Take a look and spend a few moments reading what Mike offers.
The posting is in News and Articles – Titled: ” With Better Precise Fertility Placement in Strip-till, Can we enhance Plant health and avoid Poor Stalk Conditions? October 2013″

Strip-Till and No-Till Root Systems are not the same! See what Orthman Mfg agronomy team observed.

In the News and Articles section you can read some of the latest news of a study we completed at the Orthman Research Farm this summer (2013).  Click on the following title – Orthman NTvsST root article2013  We wanted to offer a look at what did happen below ground this year and gain an appreciation for a more full rooting system in what we promote here at Orthman Manufacturing – that being “Gain an optimal root system with a 1tRIPr and sound hybrid selections”.

Fall Shows with Orthman Manufacturing – Strip-Till Is a Three Pillared Approach

As an agronomic team we are wanting to share our focus for Strip-Tillage across North America and abroad. Catch up with us at the fall Farm Shows and Demos we are carrying out across the country. Creating the premium seedbed, offering you the grower the highest quality, precise placement of your pre-plant fertilizers and last, the optimum root zone for season long results in the soil. Check us out or call!

Mike Petersen, Agronomist for Orthman has written an article (click here to read) just this month that discusses the real stuff about soil pores in Strip Tillage compared to pores in No-Till that has been studied now for 4 years at the Orthman Research and Demonstration Farm near Lexington, Nebraska.


20 row 36" 1tRIPr strip tillage machine

Spring time pore studies on Orthman Research Farm – Results!

Mike Petersen compares soil pores in Strip-Till after four years of continuous corn as well as 4 years of continuous corn in No-Till.

Coming back to the Benefits of Strip-Till and Pores in the Near Surface
Sept. 17, 2013    By: Mike Petersen, Lead Agronomist-Orthman Manufacturing

Early in the growing season we presented a blog regarding that pores were being looked at closely in the Strip-Tilled (ST) ground and No-Tilled (NT) ground at the Orthman Research Farm.  We have looked at this and 101 other details throughout the season and feel it is the right time to offer you some thoughts and conclusions.  My intern and I dug more soil pits than he cares to remember as he is deep into his college studies now, some of them when the temps were touching 100°F by 2:00 in the afternoon.

Developing the 10cm x 10cm block

During my stint of 34 years with USDA as a soil scientist we described pores, pore numbers, size, shape and continuity as we conducted soil surveys.  Pore research is intricate work and quite informative once the process and methodology is explained.  Let me be brief; pores are pretty much categorized by size – less than 1mm in diameter, 1 to 2 mm, 2 to 5mm and then greater than 5mm.  Get above that size and we are into void or holes.  Then we determine an actual count within a square decimeter (10cm x 10cm) and the pores shape.  The shape indicates whether they are old insect burrows, old root channels, solution channels, earthworm burrows and/or interstitial crevices.  All of these pores assist in the soil breathing and allowing water to move downward into the soil profile.  An observer may count several hundred pores of all sizes in native grassland soils or in soils that have suffered the fate of abundant tillage passes and heavy traffic to see less than one dozen in the square decimeter.  Essentially like concrete and impervious to water.

Our study at the Orthman Research Farm was fairly complete in that we looked at 27 in-field locations within the ST and 21 sites for the NT practice.  We made these observations after 4 years of continuous corn of NT and ST and moving the location of planting corn over 15 inches each year then digging out our blocks between the existing corn right after planting as corn was emerging.


Excavate a 30cm x 30cm block of soil from between the rows of emerging corn, shave off the upper two inches where all the residue was on top and the loose soil from winters freeze-thaw repeated and fluffed the soil surface.  Next we cut out with a sharp knife a 10cm x 10cm block that essentially allowed us to observe the 2 to 6 inch portion of the soil profile. Shaved the four surfaces flat when moist and with the point of the knife picked each face to be expressing a raw face.  Used the blades point to etch a quadrat on the face so we could count four smaller squares and begin counting the three sizes I mentioned above in the second paragraph (not the >5mm).

We would each count until our eyes crossed (well maybe not literally but we did run out of fingers and toes numerous times!) The observations are completed with a 10 magnification geologists hand lens and recorded.

Our results of the Pore Counts:
Table 1.  Data from the Strip-Tilled and No-Tilled sites at Orthman Farm, continuous corn from 2009-2014 and tillage practices remained in same rows all 4 years. Pores counted on 10cm x 10cm soil blocks from the 2 to 6 inch depth.

Location ST <1mm ST 1-2mm ST 2-5mm ST Total NT <1mm NT 1-2mm NT 2-5mm NT Total
Site 1 295 26 7 328 97 4 4 105
Site 2 218 20 9 328 82 8 3 93
Site 3 211 13 2 328 203 29 12 244
Site 4
Site 5 200 42 8 328 98 12 2 112
Site 6 188 59 14 328 74 6 11 91
Site 7 80 18 11 328 86 9 2 97
Site 8 96 25 5 328 142 8 7 157
Site 9 144 18 6 328 178 15 8 201
Site 10 113 12 4 328 147 11 3 161
Site 11 179 28 4 328 144 20 8 110
Site 12 149 22 7 328 81 21 8 90
Site 13 211 22 11 328 69 15 6 153
Site 14 242 32 20 328 135 15 3 131
Site 15 288 41 22 328 115 14 2 180
Site 16 326 39 30 328 155 17 8 204
Site 17 279 23 13 328 181 15 8 105
Site 18 176 18 13 328 99 4 4 107
Site 19 139 10 4 328 184 3 3 190
Site 20 135 21 14 328 89 9 2 100
Site 21 149 14 6 328 97 12 7 116
Site 22 106 12 9 328 100 12 5 117
Site 23 142 13 6 328
Site 24 137 14 8 328
Site 25 97 17 8 328
Site 26 113 12 7 328
Site 27 251 9 7 328
Mean 178.4 21.8 9.2 218 122 12.73 5.45 140.18
Median 154 18 8 98 12 6 124

Table 2. The range in pore counts for all sites at Orthman Research Farm

Pore Sizes ST-hi NT-hi ST-mean NT-mean ST-low NT-low
1mm 326 203 178.4 140.2 80 69
1-2mm 41 29 21.8 12.7 9 2
2-5mm 29 11 9.2 5.5 2 2

As you contemplate all the numbers there is definitely a trend that strip till has some higher counts in all three pore sizes, even as we look at the lowest counts on the right side of Table 2 for ST-low and NT-low. I will provide some clues and observations as to what I believe has occurred here over the four years of the side-by-side tillage comparisons.

Discussion and Conclusions:
As we made these observations we also excavated 30cm x 30cm blocks and pulled them apart and counted earthworms at the same time of the pore counts. Think about it, earthworms burrow and leave nice round tunnels – PORES. Who is helping out both tillage systems, certainly the “Tunnel Kings of the Earth”. Our worm counts ranged from 8 to 36 earthworms per square foot in mid-May.
Because we at the Orthman Farm alternate each year where we run the 1tRIPr tool between the previous year’s corn row we allow the old corn crown to remain and disintegrate slowly where worms are very active and those root channels/holes are routes and places for earthworms to live, breed and eat. Our tillage from what we have seen encourages worms to move in and out of the till zone (soil density is generally less than where it is easier to burrow and leave tunnels and burrows. I have been observing this now for 32 years. During this four year side-by-side study and digging during the growing season I have seen and pointed out to whoever is with me that in the NT surface compaction becomes problematic with row crop systems with tractor, combine and grain cart traffic. This has broken down soil pores in this 2 to 6 inch zone where we carry out the soil pore counts. With strip-till we can alleviate this in the spring and see more pores in the spring months.

Figure 1: Pore counts in comparing high counts and mean values between Strip-Till (ST) and No-Till(NT), 2013

In this graphic we compare the ST high counts of pores to the NT high numbers along with what the mean values of the counts. In the green text box you can read that the Strip-Till numbers are slightly fewer than the highest counts made in the No-Till

Figure 2: Total pore counts, mean values compared as Strip-Till and No-Till and the lowest number of pores for each tillage type

In the above chart (Fig 2) I offer a different look at the mean pore count numbers and the lowest numbers of pores counted to demonstrate the differences.
As I consider all what is here and the 1300+ root pits I have engaged into and then thousands of holes when I was involved in the National Soil Survey Program in 4 different states as a soil scientist, it is my opinion we see consistently more of all three major pore sizes in a Strip-Tillage System. Will it always be 25 to 40% more in numbers? No. If any conservation tillage farmer really makes a serious program to control all season traffic in and out and across of their fields the pore counts will be pretty close to the same. At the Orthman Farm we carry out harvest operations with grain carts moving all about to load and unload the combine to keep the harvest smooth and quick, similar to large corn growers in the Great Plains. We are confident that our tillage efforts will take care of 98% of all issues.
So as I conclude that as we advocate Strip-tillage, we will see more pores (three sizes We have observed that earthworms like to burrow deep in the tilled zones deep into the non-till zone of the strip-till and feed on the surface and then return. The diminished effort they have to make in the strip-till allows them quicker access to the previous crops residue. As they return to their burrows they stabilize the burrows due to their skin secretions making for larger conduits for water to enter the soil subsoil’s and substratum or underlying layers. Roots follow these tunnels with ease and I have observed 2 to 5 roots going on down one burrow frequently in the thousands of pits I have dug. Yes it sounds weird but folks, this is what makes the soils so dynamic and helpful to support healthier crops, improve soil sustainability and ultimately better yields.
All of the above offers to the grower a better chance to improve output of each seed he/she plants. I ask then, sharing our evidence and facts that soil physical characteristics do respond positively in the strip-till system to make a difference, it begs the question: are you helping your soils?

Download a copy of the report here: Benefits of StripTill_pores2013.

Strip-till water effects

Agronomist Mike Petersen documents soil pores in strip-till corn.

Orthman researchers are constantly looking for ways to help producers. Here, agronomist Mike Petersen and agronomy intern Logan Brown are studying “soil pores,” the tiny holes in soil that allow water to ‘infiltrate’ (soak into) the soil, getting this precious supply to the roots rather than letting it run-off or evaporate.

Mike is within one inch (“near surface”), using a 10X magnifying lens to determine how many and what size of pores there are in the soil. Look for details of this soil characteristic study in upcoming weeks.