Effects of recent cold rain on corn seedling viability and stand establishment

This morning I am getting lots of questions about what impact yesterday’s cold rain had on corn stand establishment. The short answer is the cold rain likely had very little impact on seed viability or final stands. For a further explanation, I would like to point you to a very well done video explanation by our new DeKalb Technical Agronomist, Nicole Stecklein. She is very knowledgable in agronomy and I encourage you to get to know her after meetings and other co-sponsored Liqui-Grow/DeKalb events.

Corn on Corn Management

photo of rows of corn for decorative purpose


Dr. Brad Bernhard discusses the key management factors needed to overcome the yield penalty when planting corn on corn.


  • Residue Management
    • bury or size the residue


  • Nitrogen Management
    • keep nitrogen fertilizer and residue apart


  • Starter Fertilizer
    • helps plants overcome early season nutrient deficiencies


  • Field Selection
    • select high yielding fields


  • Foliar Fungicides
    • disease protection


  • Hybrid Selectionge
    • stress emergence, yield stability, and disease package

Agronomy Research Summary Book 2019

Since the spring of 2015 we have been conducting research on new products and management practices farmers can potentially use to increase both corn and soybean yields and profitability. By now I have amassed a bunch of results that are finalized and ready to share.

These results are now in the form of a book, which contains research on fertilization products and practices, seed treatments for soybeans, fertilizer additives and much more. These research summary books are now available at all of our Liqui-Grow locations. You can also download the PDF or request a book by calling the main office (563-359-3624) or email Tammie Suhl at

We plan to print updated books every year to keep you well informed.

photo of Dr. Jake Vossenkemper
Dr. Jake Vossenkemper
Agronomy Research Lead

Managing for Higher Corn Plant Populations

photo of rows of corn for decorative purpose

Article Summary

  • Higher plant populations can be managed by planting in narrower row spacings.
  • As plant population increases, the size of each individual root system becomes significantly smaller, which increases the need for better crop management especially fertility.
  • When growing corn at higher plant populations and/or narrower row spacings, it is important to select a hybrid that has a positive yield-response to these more intensive management practices.

Corn yields have increased significantly since the 1930s largely due to genetic improvement and better crop management. Grain yield is the product of the number of plants per acre, kernels per plant, and weight per kernel. Of the three components that make up grain yield, the number of plants per acre is the factor that the grower has the most direct control over. Kernel number and kernel weight can be managed indirectly through proper fertility, weed, pest and disease management to optimize plant health, and weather also plays a major role. Currently the average U.S. corn planting population is just under 32,000 plants per acre and has increased 400 plants per acre per year since the 1960s. If this trend continues, the average U.S. corn planting population will reach 38,000 plants per acre in 15 years and 44,000 plants per acre in 30 years.

Narrower Row Spacings

Today, the vast majority of corn in the U.S. is planted in 30” row spacings, with narrower rows generally defined as any row spacing or configuration less than 30” row spacings.

The most common narrower row spacings include 20” and 15” rows, along with twin rows that are spaced 7.5” apart (22.5” between rows, but are on 30” centers). Narrower row spacings can be used to increase plant-to-plant spacing within a row to reduce crowding at higher plant populations, thereby, allowing the crop to better utilize available light, water, and nutrients
(Figure 1).

In 2017 and 2018, six commercial DeKalb hybrids were planted at 38,000, 44,000, 50,000, 56,000 plants per acre in a 30” and 20” row spacing at Yorkville and Champaign, IL.

30 inch rows of corn and 20 inch rows of corn

Figure 1. At the same plant population of 44,000 plants per acre, greater plant-to-plant spacing is achieved in the 20” row spacing compared to the 30” row spacing.

The management system that resulted in the highest grain yield of 294 bushels per acre was planting 44,000 plants per acre in a 20” row spacing (Table 1). The minimum plant population that maximized grain yield in a 30” row spacing was 38,000 plants per acre. On average, across plant population, plants in a 20” row spacing yielded 12 bushels per acre more than when planted in a 30” row spacing, however, as plant population increased the yield advantage of the 20” rows over the 30” row spacing was greater. Planting 56,000 plants per acre at either row spacing was too high of a population and yield decreased without a sufficient amount of resources such as water or nutrients to support that many plants. Evidence suggests that there is a limit on how high planting population can be pushed in either a 30” or 20” row spacing without any additional fertilizer, crop protection, or irrigation.

Better Crop Management

Management systems that decreased plant-to-plant spacing within a row, such as wider row spacing and higher plant population, decreased the size of the root system. On average, for every additional 6,000 plants planted per acre there was a 15-18% decrease in the size of the root system (Figure 2). However, when planted in a 20” row spacing, the greater plant-to-plant spacing increased the size of the root system by 22%. At higher plant populations, not only are there more plants that require nutrients and water, but each of those plants also have a significantly smaller root system. Crop fertility becomes even more important under these more intensive growing conditions. Placing nutrients directly in the root zone at the right time using the correct source and rate increases the probability that roots will take up and utilize those nutrients.

For every additional 6,000 plants planted per acre there was a 15-18% decrease in the size of the root system.

Comparison of corn roots based on 20 and 30 inch row spacing

Figure 2. Individual plant root size decreases as plant population increases. At a given plant population, the 20” row spacing has a larger root system compared to the 30” root system.

Select the Right Hybrid

Hybrids vary greatly in their response to plant population and to narrower row spacings (Table 2). Hybrids also vary in their plant architecture and leaf trait characteristics. Understanding which hybrids better tolerate higher plant populations and narrower row spacings along with the plant growth and leaf traits that these hybrids possess would help lead the breeding effort for selecting hybrids that will perform even better in these management systems. Hybrids that produced greater yields in response to narrower row spacings and higher plant populations tended to possess the following plant growth and leaf traits: 1) greater above-ground biomass, 2) high leaf area index, 3) upright leaves, 4) thin leaves, and 5) less leafy plants.

Table 1. Grain yield as influenced by plant population and row spacing for corn averaged across six corn hybrids grown at Yorkville and Champaign, IL in 2017 and 2018.

table comparison of yields based on plants per acre and the row spacing

Table 2. Grain yield and profit difference between planting 38,000 plants per acre in a 30” row spacing compared to 44,000 plants per acre in a 20” row spacing for six DeKalb corn hybrids grown at Yorkville and Champaign, IL in 2017 and 2018. Profit was calculated using $3.50 corn and $320.00 per bag of corn seed.

Table with hybrid comparisons


As the trend of increasing planting populations continues, it is important to consider the effects that the reduced plant-to-plant spacing has on the corn plants. Crop management becomes even more important, especially fertility, under these crowded conditions. Narrower row spacings can be used as a tool to reduce the plant-to-plant competition at higher planting populations.

Late Planting & Fall Killing Frost Concerns

The 2019 growing season has been anything but “normal” thus far. We have had well above normal precipitation, below normal heat unit accumulation and delayed planting. Moreover, the extended 3 month forecast published by NOAA and the National Weather Service calls for higher than normal probabilities of precipitation and lower than normal temperature probabilities thorough out the remainder of the summer (figures 1 & 2).

3 month outlook of precipitation probability for the continental USA
Figure 1. NOAA 3 month precipitation outlook
3 month outlook o3 month outlook temperature  probability for the continental USA
Figure 2. NOAA 3 month temperature outlook.

These facts have resulted in many sales agronomist and growers wondering if the crop will make it to black layer (maturity) prior to a killing frost? To help answer these questions I have used a decision support weather model/tool developed by the Midwest Climate Center and their affiliates to help derive some insights into this question.

To help answer this question I plugged in 3 hypothetical planting dates (May 25th, June 5th and June 15th) into the U2U weather/GDD model, and three different maturities spanning early to full maturity corn hybrids. I also ran the U2U weather tool at 4 different latitudes. A latitude approximating Roseville, IL, Davenport, IA, Clear Lake/Hampton, IA and Elkhorn, WI. While I won’t take the time to carve through all the graphs and data, I will give a brief synopsis of my findings.

Fun fact, the definition of a killing frost is when temperatures reach 28 degrees F or colder. This temperature is usually cold enough to turn water within plant cells into ice crystals. These expanding ice crystals burst cells and are usually lethal to the entire plant. Hence “killing frost”.

Roseville, IL & Davenport, IA Latitudes

In general I found that hybrids ranging from 104 RM to 114 RM have a high probability of making it to black layer prior to a killing frost at the Roseville, IL and Davenport, IA latitudes (figure 3 & 4) when planted by May 25th or earlier planting dates. For hybrids planted on June 5th, it looks like the 104 to 110 day RM hybrids will also have a good chance of making it to black layer prior to a killing frost, but very full hybrids (113 to 114 RM) may experience a killing frost prior to black layer at these latitudes (figure 3 & 4). Any hybrid (104 to 114 RM) planted on or after June 15th at the Roseville, IL and Davenport, IA latitudes has a 50% chance or greater probability of experiencing a killing frost prior to black layer.

Graph to show percent change of killing frost
Figure 3: The % chance of corn hybrids reaching black layer prior to a killing frost for 3 hypothetical planting dates at latitudes close to Roseville, IL, Mt Pleasant, IA & Morning Sun, IA.
Graph to show percent change of killing frost
Figure 4: The % chance of corn hybrids reaching black layer prior to a killing frost for 3 hypothetical planting dates at latitudes close to Davenport, IA.

Clear Lake & Hampton, IA & Elkhorn, WI Latitude

For the latitude’s close to Elkhorn, WI any mid and short-season hybrids (95 to 101) planted on or before May 25th have a greater than 50% chance of making in to black layer prior to a killing frost, but full maturity hybrids (107) even when planted on May 25th have a poor chance of making it to black layer prior to a killing frost (figure 6). If corn was planted on June 5th only the short-season hybrids (95) hybrids have a good chance of making it to black layer before a killing frost at this latitude (figure 6). For regions close to this latitude all RM hybrids (95 to 107) planted on or after June 15th don’t seem to have a good chance of making it to black layer if we have a normal frost date (Oct 18th) for this region. But most full-season hybrids at this latitude are grown for silage, so a killing frost is likely not to be a concern for those silage acres given harvest is much sooner than when harvesting for grain.

Graph to show percent change of killing frost
Figure 5: The % chance of corn hybrids reaching black layer prior to a killing frost for 3 hypothetical planting dates at latitudes close to Clear Lake and Hampton, IA.
Graph to show percent change of killing frost
Figure 6: The % chance of corn hybrids reaching black layer prior to a killing frost for 3 hypothetical planting dates at latitudes close to Elkhorn, WI.

The Good News

While a killing frost sounds devastating to yield, a killing frost when grain yield is still rapidly accumulating during mid and early reproductive growth/development is rare. The more likely scenario is that we may experience a killing frost very late in the grain filling period (also known as reproductive growth period). A killing frost at 35 to 40% kernel moisture usually has negligible effects on grain yield, given all yield has nearly been accumulated. A rarer scenario is that we could experience a killing frost at half milk line, this could result in more severe yield losses, (10 to 15% range), slower field drying, difficulty shelling kernels from cobs and poor test weight. The best scenario for us all would be a warm dry fall.

2019 Nitrogen Loss and Recommendations

How to Correct the Nitrogen Loss

Nitrogen loss will be a big concern in 2019 given all the wet weather. As such and for good reason, there have been many questions regarding how much N may have been lost and what we can do to go about correcting these N loss problems. To address these concerns and questions I have made a video discussing these various issues. As you will learn in this video I will produce a second video with PSNT soil test results and nitrogen model estimations of N loss which may refine my initial thoughts and recommendations. 2019 is off to a rough start, but the more in-the-know you are, the better your yield.

  1. If you had more than 10 inches of rain since N was applied its advised that you recommend applying more. Nitrate soil tests are confirming this.
  2. N models don’t seem to be aligning very well with the nitrate nitrogen tests that I took and some general knowledge about what we know regarding rain fall amounts and precipitation.

Bottom line, N models may be valuable, but they don’t replace good sound experience and agronomic advise. Follow recommendations from N models with caution.


– Dr. Jacob Vossenkemper (Agronomy Research Lead)

New Research Comparing Ortho/Poly-Phosphate Ratios


Blog Banner for Poly Phosphate study


  • Ortho-phosphates are 100% plant available, but a high percentage of poly-phosphates in starter fertilizers convert to ortho-phosphate within just two days after application.
  • This quick conversion from poly to ortho-phosphate suggests expensive “high” ortho starter fertilizers are not likely to result in increased corn yields compared to conventional poly-phosphate starters.
  • On-farm field studies conducted near Traer, IA and Walnut, IL from the 2016 to 2018 growing season found no statistical difference (Pr > 0.05) in corn yield between conventional and high ortho-phosphate starters.
  • High ortho starters cost more per/ac than conventional poly-phosphate starters, but do not increase corn grain yields.

Poly-phosphates Rapidly Convert to Plant available Ortho-Phosphates

Given poly-phosphates are not immediately plant available and ortho-phosphates are immediately plant available, this gives the promoters of “high” ortho-phosphate starters ample opportunity to muddy the waters. Nevertheless, the facts are, poly-phosphates are rather rapidly hydrolyzed (converted to) into ortho-phosphates once applied to soils, and this hydrolysis process generally takes just 48 hrs or so to complete.

In Sept of 2015 I posted a blog discussing some of the more technical reasons why the ratio of ortho- to poly-phosphates in starter fertilizers should have no impact on corn yields. For those that are interested in the more technical details, I encourage you to follow this link to
the Sept 2015 blog post (

While we were relatively certain that the ratio of ortho to poly-phosphates in liquid starters should have no effect
on corn yields, I decide to “test” this idea with on-farm field trials located near Traer, IA and Walnut, IL  in the 2016, 2017 and 2018 growing seasons.

tractor planting fertilizer

Picture 1. Planting starter fertilizer trials near Traer, IA in the growing season of 2016.


How the Field Trial Was Conducted

In these field trials we used two starters applied in-furrow at 6 gal/ac. Each starter had a NPK nutrient analysis of 6-24-6. The only difference between these two starters was the ratio of ortho to poly-phosphates. One of these starters contained 80% ortho-phosphate and the other contained just 50% ortho-phosphate. With the remainder of the phosphorous source in each of these two starters being poly-phosphate. At the Traer, IA locations the plots were planted with a 24-row planter (picture 1) and were nearly 2400ft long. At the walnut, IL locations the research was conducted using small plot techniques, plot dimensions there were 10 ft wide by 30 ft long. At both Traer, IA and Walnut, IL in each of the 3 growing season the experimental design used was a simple randomized complete block with 4 or 5 replications.

Figure 1. Average corn yield from field trials comparing high ortho vs conventional poly-phosphate in-furrow seed safe starter fertilizers. Yields at each location/year are averaged over 4 or 5 replications.


Figure 2. Partial profit from field trials comparing high ortho vs conventional poly-phosphate in-furrow seed safe starter fertilizers. Yields at each location/year are averaged over 4 or 5 replications. Partial profit was calculated using a grain sale price of 3.50 bu. Cost per gal used to calculate partial profit for the 6-24-6 50% ortho & 50% poly-phosphate and 6-24-6 80% ortho & 20% poly-phosphate was $2.80 and 3.20 per/gal


Field Trial Results

Averaged over the 5 site-years there was only about 1.5 bu/ac yield difference separating the high ortho and conventional poly-phosphate starter (figure 1). Moreover, this small yield difference was not statistically significant (Pr > 0.05). In addition to finding no differences in grain yield between these two starters, the high ortho starter cost about $0.50 more per/gal (so $3/ac difference in price at a 6 gal/ac rate) than the lower ortho starters. So the more expensive high ortho starter clearly did not “pay” its way in our multi-location field trials (figure 2). Lastly, our observations in these studies agree with previously published university findings (Frazen and Gerwing. 1997).


Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. (accessed 8 of Sept 2015).


– Dr. Jacob Vossenkemper (Agronomy Research Lead)

Urea – A Poor Choice of Nitrogen Fertilizer for In-Season N Applications

John Deere tractor in corn field



  • Urea fertilizer, if not incorporated by tillage or precipitation, is highly susceptible to ammonia volatilization (loss to the atmosphere as ammonia gas).
  • Uniform application of urea can be problematic due to segregation of larger and smaller urea prills and due to physical spread pattern interference from standing corn during in-season applications.
  • Liquid UAN (32 or 28%) is only 50% urea and is about half has susceptible to ammonia volatilization as dry urea.
  • Banding UAN further reduces the probability of nitrogen loss via ammonia volatilization.
  • Averaged over 3 on-farm plots side-dressing surface banded UAN gave 16.2 $/ac greater net returns and yielded 5.5 bu/ac more than surface broadcasted urea.

Urea, anhydrous ammonia and liquid urea ammonium nitrate (UAN 28 or 32%) are by far the most common sources of nitrogen fertilizer used in corn production. Moreover, all 3 sources of nitrogen fertilizer have their own unique advantages and disadvantages, but in particular, dry urea is an exceptionally poor source of nitrogen for in-season applications to corn. At first glance, urea seems to be an attractive in-season nitrogen source, because it can be applied rapidly with high clearance dry spinner spreaders and urea is commonly a few cents per lb of nitrogen cheaper than UAN. Urea, however, is highly susceptible to N loss via ammonia volatilization and uniform fertilizer nitrogen distribution can be a serious problem for top yields and maximizing economic returns.

Dry Urea: Elevated Risk for N Loss via Ammonia

Ammonia volatilization occurs when the urease enzyme hydrolyzes urea fertilizer to ammonia on the soil surface. Given ammonia (NH3) is a gas and lighter than air, the ammonia literally floats away into the atmosphere. The most effective way to prevent ammonia volatilization is for urea hydrolysis to occur beneath the soil surface where the ammonia gas can interact with hydrogen ions to form ammonium (NH4+).

To avoid serious N loss, urea must be incorporated with tillage, moved below the soil surface by precipitation or subsurface injected. For in-season N application, however, physical incorporation or injection of dry urea is not practical, leaving a rainfall event that must exceed 0.5 inches to move the urea below the soil surface (figure 1). This significant rainfall event must occur no later than 4 days after urea application (figure 2) or N loss from ammonia volatilization could drastically accelerate in subsequent days (Jones et al., 2013). UAN is also susceptible to ammonia volatilization, but only 50% of the nitrogen in UAN is urea. Therefore, UAN is roughly half as susceptible to ammonia volatilization as dry urea.

irrigation rate graph

UAN also provides more flexibility regarding in-season applications than dry urea. UAN can be subsurface injected or surface banded within the row. Subsurface injection of UAN strongly reduces the potential for ammonia volatilization because urea hydrolyses occurs below the soil surface. Banding UAN on the soil surface does not eliminate ammonia volatilization, but reduces the risk of ammonia volatilization considerably (figure 2, Jones et al., 2013). The reduction in ammonia volatilization risk with banding UAN occurs because banding physically reduces the amount of N fertilizer exposed to the urease enzyme.

Field with low Urea rate stripes

Poor Fertilization: Increases Yield Loss Risk

Achieving uniform application with dry fertilizer, which includes urea, can be a difficult task. Several problems exist that can lead to non-uniform urea applications. If urea is not uniformly sized, the result is segregation of larger and smaller urea particles during loading, transportation to the field and during spreading. Particle segregation is a problem because larger urea granules are thrown further from the dry spinner spreader machine than smaller particles, resulting in a higher application rate directly behind the machine and a lower applications rate at the edges of each pass.

Segregation is not the only concern. When side-dressing corn, poor urea distribution can be exacerbated by the standing corn crop, particularly when corn reaches over a few feet in height. Tall corn acts as a funnel, cutting down the distance at which the urea granules can be thrown compared to when no crop was present to disrupt the flow of urea toward the edges of each pass.

On-Farm comparisons: Broadcast Urea vs. Surface Banded UAN as In-Season N Sources

The on-farm studies were conducted at 3 locations in the 2016 growing season. The locations included Elkhorn, WI, Tipton and Morning Sun, IA. The base and side-dress N rates used at each location are listed in table 1. At each location the side-dress nitrogen was applied at growth stages between V6 to V8 as either surface banded UAN or surface broadcasted urea. At each location these treatments were replicated 3 or 4 times. The price of UAN and urea used to calculate partial profit was 0.36 and 0.32 $/lb N. The price of corn used to calculate partial profit was 3.50/bu.

Surface Banded UAN vs Surface Broadcasted Urea chart

Averaged over the 3 locations yields were increased 5.5 bu/ac from surface banded UAN when compared to surface broadcast urea (table 2 and figure 3). In addition to higher yields from surface banding UAN vs broadcasting urea, net profits were 16.2 $/ac higher for the surface banded UAN treatments, despite slightly higher nitrogen costs (table 3).

Table 1table 2table 3


Because urea cannot be physically incorporating post-planting, it is susceptible to loss via ammonia volatilization (loss to the atmosphere as NH3 gas). Moreover, uniform application with dry fertilizer, including urea, can be problematic due to segregation of larger and smaller urea prills and due to physical spread pattern interference from standing corn. For these reasons, urea is a particularly poor source of nitrogen fertilizer for in-season applications. In these 3 on-farm trials surface banding UAN increased yields 5.5 bu/ac and net profits 16.2 $/ac compared to surface broadcasting dry urea.


Jones, C., B.D. Brown, R. Horneck, D. Olson-Rutz. 2013. Management to Minimize Nitrogen Fertilizer Volatilization. Extension Publication EB0209. Montana State University. /soilfertility/documents/PDF/pub/UvolBMPEB0209.pdf.


– Dr. Jacob Vossenkemper (Agronomy Research Lead)

Tar Spot Update


Last week Dr. Damon Smith, with the University of Wisconsin, gave an update on Tar Spot and I thought his findings were extremely valuable and the most relevant information I have seen to date.

Tiny black spots against a brown lesion are a symptom of the tar spot complex in corn.

Two corn kernels graphic


- Tar Spot can overwinter and has been in WI for 3 years. It is also in Eastern IA. The first two years Tar Spot was in Wisconsin, it did not infect plants until late August. This year it arrived Mid-June.

- There hasn’t been a single plant found with the Monographella version (the really bad type only found in Mexico so far)

- Tar spot is causing yield loss in the absence of any another disease, such as grey leaf spot.

- Hybrid tolerance incredibly variable. Some can handle it, some take a huge yield hit with this disease.

- Early hybrids take less of a hit. Research is showing that at 10% of the leaf area covered with Tar Spot yields are reduced by 8 bu/ac. Longer maturity (103-113 day) hybrids lost 15 bu/ac when 10% of the leaf area was infected.

- University plant pathologist are creating a phone app (the TarCaster) that will hopefully be able to predict the arrival of the disease based on the weather. They already have a similar program for predicting white mold. They expect that to be out for testing this upcoming year.

- Yield losses appear to be dependent on when the plants become infected with Tar Spot. For example, this year infection started between V8 and VT is some regions but in previous years infection did not start until after milk stage.  There is barely a hit on yield if it arrives during the Milk stage.

-Fungicide does help if timed properly, and at least Headline Amp and Delaro are labeled for Tar Spot.

-University plant pathologist plan on releasing a fungicide update around the end of December to show when the optimum time will be for applying fungicides to control/suppress Tar Spot.

What are Liquid Suspension Fertilizers

And Should I Consider Using Them On My Farm?


  • Liquid fertilizers offer some unique advantages compared to dry granular fertilizers:
    • Accurate nutrient application distribution
    • Can be tank mixed with many pesticides
    • Macro and micro nutrients can be evenly blended
    • Can be easily surface or subsurface banded
  • Liquid suspension fertilizers offer the same unique advantages and are cost competitive with dry granular fertilizers.
  • A recent summary of 39 science-based studies showed that banding fertilizer reduced phosphorus fertilizer fixation in the soil, caused roots to concentrate in nutrient rich fertilizer bands, and resulted in increased nutrient uptake and 4.5% higher corn yields.
  • Local on-farm research shows that surface banding liquid suspension fertilizers on 15" centers increases corn yields by 4.2 bu/ac and profitability by 16.7 $/ac compared to broadcasting equivalent rates of dry granular fertilizer.

Liquid Fertilizers – Some Unique Advantages

Liquid fertilizers offer unique advantages over dry granular fertilizers. Liquid fertilizers can be applied extremely accurately, can be tank-mixed with many different pesticides, and micro nutrients can be evenly blended in liquid solutions. These factors result in uniform nutrient application for both macro and micro nutrients, and increased profitability due to higher crop yields and fewer trips across a field when compared to dry granular fertilizers.

Liquid fertilizers offer unique advantages over dry granular fertilizers.

Graphic of two corn kernels.

Liquid Suspension Fertilizers – Unique Advantages at Affordable Costs

Liquid suspension fertilizers provide the same agronomic and economic advantages as clear liquids (starter fertilizer, foliar sprays, those used in drip tape or over the top irrigation systems), but are more reasonably priced than clear liquids.

How can this be?

FIRST: the phosphoric acid used to make the phosphorus fertilizer source in liquid suspensions takes fewer manufacturing/processing steps than the phosphoric acid used to make starter fertilizer-grade clear liquids.

SECOND: in liquid suspensions, a small amount of clay is used to keep fertilizers suspended in a liquid solution. This is particularly important for the potassium source used to make liquid suspension fertilizers.

For example, without the added clay, only about 1 lb of potassium chloride could be dissolved in 1 gallon of water, but with the addition of a small amount of clay, that same 1 gallon of water can hold about 3 lbs of potassium chloride. Liquid suspensions are higher analysis fertilizers (higher % plant nutrients per/gallon material), which reduces transportation costs. When lower transportation cost are paired with more cost-effective raw materials, liquid suspensions can be priced lower than clear liquids, and are cost-competitive with dry granular phosphorus and potassium fertilizers.

Three-panel graphic of corn plant spreading roots into fertilized areas of the soil
Figure 1
Fertilizer Source N-P-K-S-ZN-B Rate lb/ac Yield bu/ac Fertilizer Cost $/ac Net Return $/ac
Liquid Dribble Band 21-50-75-15-0.5-0.2 231.2 47.1 +16.7 $/ac Liquic
Dry Broadcast 227 44.8 Dribble Band

Table 1

Banding Liquid Suspensions for Increased Fertilizer Nutrient Uptake and Crop Yields

Bar graph showing 3% increase in soybeans and 12% more in corn.
Figure 2. Nutrient uptake changes from banding vs broadcasting equivalent rates of ammoniated phosphorus fertilizers. Adapted from Nkebiwe, et al., 2016.

Besides being cost-effective, liquid suspensions are extremely easy to surface or subsurface band.

Banding nutrients achieves two goals: reduced phosphorus fertilizer fixation with Ca2+, Al3+, and Fe3+, and roots become highly concentrated in nutrient-rich fertilizer bands (figure 1). As a result of reduced phosphorous fertilizer fixation (tied up in non-plant-available forms) and increased root activity in nutrient-rich fertilizer bands, the amount of applied fertilizer that is taken up by both corn and soybean crops is increased. In fact, a group of crop scientist recently organized 39 science-based studies with the objective of comparing the effects of banding vs broadcasting fertilizer phosphorus on nutrient uptake and crop yields (Nkebiwe et al. 2016). Averaged over 112 comparisons of banded vs broadcasted phosphorus fertilizer sources, they found that banding phosphorus fertilizer increased nutrient uptake by 12% (figure 2) and corn yields by 4.5% (9 bu/ac or $31/ac at 200 bu/ac yield level) compared to broadcasting the phosphorus fertilizer sources.

Fertilizer Applications—Advantages and Disadvantages

Graphic of a corn plant subjected to broadcast fertilizer

Dry Broadcasting


  • Many acres can be covered rapidly
  • Low application costs


  • Application uniformity is poor and can result in reduced crop yields
  • Broadcasting results in fertilizer fixation in the soil and lower crop nutrient uptake when compared to banding fertilizer
  • Blended dry fertilizers sift or segregate during transportation and handling which can lead to lower or higher fertilizer applications rates than intended
Graphic of a corn plant subjected to subsoild band-applied fertilizer

Subsurface Banding


  • Application uniformity is very consistent
  • Replenishes subsoil plant nutrients
  • Banding reduces fertilizer fixation in the soil, increases root activity in nutrient rich bands, and leads to higher nutrient uptake and often higher grain yields
  • During dry weather, subsurface placed nutrients remain more plant-available than fertilizer nutrients placed on the soil surface
  • Eliminates the chance for fertilizer runoff during high intensity rainfall events


  • 3 to 5 times slower than broadcasting or dribble banding fertilizer nutrients
  • Slower application increases labor costs
  • Initial investment in high horsepower tractors and subsurface placement implements can be high
  • Yield increases when compared to broadcasting or dribble banding fertilizer may not always be high enough to cover added labor and equipment costs
Graphic of a corn plant subjected to dribble band-applied fertilizer

Dribble Banding


  • Many acres can be covered rapidly
  • Application uniformity is consistent for each plant
  • Banding reduces fertilizer fixation in the soil, increases root activity in nutrient rich bands, and leads to higher nutrient uptake and often higher grain yields
  • Low application costs


  • Floaters equipped with high capacity pumps and oversized hoses are needed to apply liquid suspension fertilizers

Liqui-Grow's Local On-farm Research – 2016 & 2017 Results

For the last two crop seasons (2016 & 2017), we have partnered locally with growers to compare what effects broadcasting dry granular fertilizers vs surface dribble banding liquid suspensions fertilizers has had on corn yields. These studies were on-farm strip trials set up as valid experiments with randomized treatments and multiple replications. The dry fertilizers and liquid suspension fertilizers were applied at the same plant nutrient rates per acre. These trials were located in Traer Iowa, Morning Sun Iowa, Washington Iowa, and Roseville Illinois.

In 74% of the side-by-side comparisons, surface-banded liquid suspension fertilizers produced more corn grain than equivalent rates of dry broadcasted granular fertilizers.

corn kernel graphic

We applied the fertilizer, and the farmer cooperator harvested the plots with their commercial combines.

In 74% of the side-by-side comparisons, surface-banded liquid suspension fertilizers produced more corn grain than equivalent rates of dry broadcasted granular fertilizers (figure 3). Moreover, in 68% of those side-by-side comparisons, net returns were higher for the liquid suspension fertilizers (figure 4). Overall we found that yields were increased by 2% (4.2 (bu/ac) and profit per acre was increased by $16.7/ac from banding vs broadcasting fertilizer nutrients (table 1). Our findings are similar to those recently summarized by Nkebiwe et al. 2016, and are yet another example of what effects banding has on fertilizer nutrient availability, crop nutrient uptake, and grain yields.

Banded liquid suspension yield increased graph
Figure 3. Yield increase from using banded liquid suspension fertlizers vs brodcasted dry granular fertlizers in 16 side-by-side comparisons.
Banded liquid suspension net return graph
Figure 4. Net return from using banded liquid suspension fertlizers vs brodcasted dry granular fertlizers in 16 side-by-side comparisons.


Liquid suspension fertilizers offer unique agronomic and financial advantages. These advantages include accurate fertilizer placement and distribution, macro and micro nutrients that stay blended in solution, and a product that is exceptionally easy to surface or subsurface band apply. These factors together result in reduced fertilizer fixation, increased nutrient availability, and often statistically higher crop yields and net returns than broadcasted granular fertilizers.


Nkebiwe, P.M., M. Weinmann, A. Bar-Tal, and T. Müller. 2016. Fertilizer placement to improve crop nutrient acquisition and yield: A review and meta-analysis.
Field Crops Res. 196:389–401.