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

Summary

  • 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 (liqui-grow.com/farm-journal).

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).

References

Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. http://www.extension.umn.edu/agriculture/nutrient-management/fertilizer-management/docs/Feb-97-1.pdf (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

 

Summary

  • 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

Summary

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.

Reference

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

 

– Dr. Jacob Vossenkemper (Agronomy Research Lead)

Tar Spot Update

Summary

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

Keynotes

- 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?

Summary

  • 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

Advantages

  • Many acres can be covered rapidly
  • Low application costs

Disadvantages

  • 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

Advantages

  • 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

Disadvantages

  • 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

Advantages

  • 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

Disadvantages

  • 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.

Summary

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.

References

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.

Fertilizer Placement Effects Corn Vegetative Development

Liqui-Grow is conducting extensive crop management research in the 2018 growing season in northwest, IL and eastern, IA. This year, we have implemented research at 5 different sites and am conducting 25 different experiments. These experiments include simple corn hybrid evaluations, testing new fertilizer formulations, and extensive studies looking at how bacterial inoculations may interact with various fertilization strategies to name a few. In this short educational video, I review observations we’ve made in a fertilizer placement study located in northwest, IL.

– Dr. Jacob Vossenkemper (Agronomy Research Lead)

Are Bio-fertilizers the Next Frontier in Soil Fertility and Fertilizer Technology?

research tractor in the fieldThat is yet to be determined of course, but we do know that the biological and bio-fertilizers market is estimated to grow from a current market worth of $6.7 billion to $12.9 billion by the year 2022. What’s this mean if I am a farmer? A rapidly growing biological market aimed at the agricultural sector means farmers need to become educated about what biologicals and bio-fertilizers may and may not be able to offer them. Over the last 4 months or so I have been browsing the scientific literature educating myself about what we do and do not know about these bio-fertilizers. I have learned that due to advancements in genome sequencing it is now much easier, faster and cheaper to identify and isolate specific bacterial and fungal strains that do in-fact provide services that can improve plant growth and yield.

Some of the agronomically important services bio-fertilizers may be able to provide include: atmospheric nitrogen fixation for cereal crops (corn, wheat, etc..), bacteria that are able to convert non-plant available forms of soil nutrients into plant available forms (phosphorus and potassium solubilizing bacteria), bacteria that can compete with plant pathogenic fungi and other harmful bacteria, and specific strains of bacteria have been shown to produce plant growth regulators (Indole acetic acid and gibberellic acids) that can stimulate root growth and development. See the bulleted list below for more specific details about what bio-fertilizers have been shown to be able to achieve is science-based studies.

Bio-Fertilizers 2018 Field Testing

Tractor in Field for Bio Fertilizer

The unfortunate part is that many of these known benefits of bio-fertilizers have been tested more often under greenhouse vs. actual field conditions. That said, there is an increasing amount of evidence that these bio-fertilizers may, in fact, be able to increase corn and soybean yields in actual field environments, but our knowledge in actual field conditions is clearly more limited than what has been shown in greenhouse studies. On this note, Liqui-Grow has partnered with several biological companies that are leaders in the bio-fertilizer market. We will be testing their most promising bio-fertilizer products at several locations throughout eastern, IA and northwest, IL in the 2018 growing season. My main objective at Liqui-Grow is to identify and investigate (in-formal field research trials) new and innovative products and crop management practices that can make our customers and our company more profitable – partner with us to find out what we learn.

Known Agronomically Important Services Bio-fertilizers Can ProvideBacteria

  • Nitrogen-fixing bacteria can add 25-45 lbs N/ac/yr (Azospirillum, Azotobacter) under optimum soil conditions and thereby can increase crop yields 15-25%.
  • Application of bio-fertilizers results in increased mineral and water uptake, root development, and vegetative growth.
  • Some bio-fertilizers (eg, Rhizobium BGA, Azotobacter sp) stimulate the production of growth promoting substance like vitamin-B complex, Indole acetic acid (IAA) and Gibberellic acids.
  • Phosphate mobilizing or phosphorus solubilizing bio-fertilizers/microorganisms (bacteria, fungi, mycorrhiza etc.) converts insoluble soil phosphate into soluble forms by secreting several organic acids and under optimum conditions, they can solubilize/mobilize about 30-55 lbs P2O5/ac due to which crop yield may increase by 10-20%.
  • Bio-fertilizers act as antagonists/competitors and suppress the incidence of soil-borne plant pathogens and thus, help in the bio-control of diseases.
  • Nitrogen-fixing, phosphate mobilizing and cellulolytic microorganisms in bio-fertilizer enhance the availability of plant nutrients in the soil and thus, sustain agricultural production and farming system.
  • Bio-fertilizers are a cheap, pollution free and renewable energy sources.
  • Bio-fertilizers improve physical properties of soil, soil tilth and soil health in general.
  • Blue-green algae like Nostoc, Anabaena, and Scytonema are often employed in the reclamation of alkaline soils.
  • Bio-inoculants containing cellulolytic and ligninolytic microorganisms enhance the degradation/decomposition of organic matter in the soil, as well as enhance the rate of crop residue decomposition.
  • Azotobacter inoculants when applied to many non-leguminous crop plants, promote seed germination and initial vigor of plants by producing growth promoting substances.

Bio-Fertilizer Services Reference: Agriinfo

Bio-Fertilizers Field Testing

Comparing High Ortho and Conventional Polyphosphate Starter Fertilizers

2017 New Research

High Ortho and Conventional Polyphosphate Starter Fertilizers
Planting starter fertilizer trials near Traer, IA in the growing season of 2016.

Article Summary

  • Orthophosphates are 100% plant available, but a high percentage of polyphosphates in starter fertilizers convert to ortho-phosphate within just two days after application.
  • This quick conversion from poly to orthophosphate suggests expensive “high” ortho starter fertilizers are not likely to result in increased corn yields compared to conventional polyphosphate starters.
  • On-farm field studies conducted near Traer, IA in the 2016 and 2017 growing season found no statistical difference (Pr > 0.05) in corn yield between conventional and high orthophosphate starters in either year.
  • High ortho starters cost more per/ac than conventional polyphosphate starters but do not increase corn grain yields.

Polyphosphates Rapidly Convert to Plant available Orthophosphates

How the Field Trial Was Conducted

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

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

While we was relatively certain that the ratio of ortho to polyphosphates in liquid starters should have no effect on corn yields, we decided to “test” this idea with on-farm field trials located near Traer, IA in the 2016 and 2017 growing seasons.

How the Field Trial Was Conducted

In these field trials, we used two starters applied in-furrow at 6 gal/ac. Each starter had an NPK nutrient analysis of 6-24-6. The only difference between these two starters was the ratio of ortho to polyphosphates. One of these starters contained 80% orthophosphate and the other contained just 50% orthophosphate. With the remainder of the phosphorus source in each of these two starters being polyphosphate. Each plot was planted with a 24-row planter (Picture 1) and was nearly 2400 ft long. In both the 2016 and 2017 growing seasons the experimental design used was a randomized complete block with 4 or 5 replications.

on farm study near traer iowa 2016
on farm study near traer iowa 2017

Field Trial Results

Averaged over the side-by-side replications there was less than 1 bu/ac difference in corn grain yield between the high ortho and low ortho polyphosphate starters in both the 2016 and 2017 growing seasons. In addition to finding no differences in grain yield between these two starters, the high ortho starters generally cost about $1 more per/gal (so the $6/ac difference in price at a 6 gal/ac rate) than the low ortho starters. So the more expensive high ortho starter clearly did not “pay” its way in our multi-year field trials.

More Trials Planned for 2018

While our findings agree with other research-comparing ortho and polyphosphate starter fertilizers (Frazen and Gerwing. 1997), we want to be absolutely certain that our fertilizer offerings are the most economically viable products on the market. Therefore, we have decided to run this same field trial at one location in northern, IL in 2018, and at one location in central, IA in 2018. Stay tuned for those research results next fall.

Standing in front tractor on Traer, Iowa Farm | Liqui-grow

Want to learn more?

References
Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. http://www.extension.umn.edu/agriculture/nutrient-management/fertilizer-management/docs/Feb-97-1.pdf (accessed 8 of Sept 2015).