Use of Fertilizer Additives Brian Arnall Department of

Use of Fertilizer Additives Brian Arnall Department of Plant and Soil Sciences Oklahoma State University

Isn’t it true……. . � Nitrogen › Not available › NH 3 is the devil � Phosphorus › Not available › Around for a long time › Ortho P is better than Poly P

Options � They can be added too › N stabilizers/Inhibitors › P stabilizers › Low Salt and fungicides � Replacement off › Coated › Low salt/slow release › Ortho P � Or in Blends › Coated

Understanding � Should be applied for a reason › The is a problem › Or potential to increase � Not just because

Nitrogen

� Slow Release › Prevents immediate release into soil where environment and biological’s have impact. �Coated �Chemistry � Inhibitors › Prevent the biological activity that impacts the Nitrogen Cycle › Since early 60’s at least 15 substances thoroughly researched

Controlled-Slow Release � Coated Urea’s › Sulfur Coat › Polymer Coat � Urea/N › › Chemistries Isobutylidene diurea Ureaformaldehyde Urea-Triazone Methylene Urea

Controlled-Slow Release � � � � Advantage of these materials is that one application may provide a uniform supply of N to the plants for several weeks. S-coated urea (32 -36 %N) breakdown of the S coat (physical barrier) Moisture Polymer Coated Ureas ESN: Temp and Moist IBDU (isobutylidene diurea) is synthetic organic. particle size, soil moisture content and p. H. Urea-formaldehyde: microbial & temp Methylene di-urea -Co. Ro. N, Dura_N: Microbial & temp Urea-Triazon- N-Pact, N-Sure: Moist & Microbial. � LOOK AT PERCENT � 6 to 20% � Release Patterns SLOW RELEASE

Understanding polymer coating technology ESN contains a urea granule nitrogen (N) within a micro-thin polymer coating. This coating allows water within the soil to move into the granule and dissolve the urea inside. The urea solution then moves out through the coating into the soil where it is available to the crop. � The rate at which the urea solution moves out through the coating is determined by soil temperature and moisture. In cool soils when the crop is growing slowly, N release is slow. As the soil warms and crop growth increases, the granules release N more quickly and steadily. �

Low Salt Nitrogen � Yield and Protein Always equal to UAN when used as a fertilizer source. � Reduced amount of Tissue Damage � Increased rate w/ seed possible. Using 10 -34 -0 › Wheat < 30 lb N i. e. 25 gal/ac › Canola <10 lb N i. e. 8 gal/ac

Co. Ro. N at Flag Leaf w/fung Relative yield 100% is Producer Standard. 3 yr Average 125% 100% 1. 16 1. 18 1. 16 1. 21 1. 18 1. 02 1. 00 0. 80 75% 50% 25% Received Humic Acid with Top-dress 0% No flag leaf Quilt + No flag Co. Ro. N leaf Quilt + Kitchen Zero Co. Ro. N sink Fertility

Stabilizers � Two Target � Keep as Urea � Keep as Ammonia

Urea Exp. Wet Soil 70˚F 0 4 8 Wet Soil 35˚F 0 8 32 56

Urea Exp. Dry Soil 70˚F 0 8 32 56 Rain 1/2” Sub Soil 70˚F 0 4 8 0 4

UREA H 2 O: Rain, Mist, Dew, Humidity, Soil Moisture (NH 2)2 CO 2 NH 3 (gas) e as e Ur NH 4 SOI L H 2 O NH 4 SOI L

N Stabilization � Urease Inhibition › Basically prevents/slows urea’s conversion to ammonia › If ammonia (gas) is formed in absence of moisture or soil surface it will be lost to the atmosphere H 2 O (NH 2) 2 CO 2 SOIL

Urease Inhibition � NBPT: Studied since the 80’s Agrotain › 7 Day half life � (MIC) Maleic Itaconic Coploymer Ca binding of nickel ions necessary for the formation and function of the enzyme Nutrisphere › Published Results not positive

To Use or Not to Use � When › › › › less or not beneficial Incorporated Rain or irrigation of ½ “ or more Soil and air temp < 50 Dry soil and Air Banding No rain expected for 14+ days UAN vs Urea

To Use or Not to Use � When › › › › more beneficial Surface applied No-till High humidity Light rains, heavy dews, mists Soil and air temp > 50 Wet soil Soil with high p. H >7. 5 Lots of OH in soil Rain within 10 days

N Stabilization � Nitrification Inhibition › Basically prevents/slows ammonium’s conversion to nitrate › Ammonium(+) is immobile in the soil Nitrate(-) is mobile. In high rainfall, irrigated, well drained soil NO 3 is easily lost. › NO 3 can be lost by leaching and Denitrification �Both Take WATER!!!!

Nitrification

NO 3 Losses

Nitrification Inhibition � Nitrapyrin- Registered Pesticide, studied since the 60’s N-Serve, Instinct � (MIC) Maleic Itaconic Coploymer Ca binding of nickel ions necessary for the formation and function of the enzyme Nutrisphere � DCD – Suppresses, does not kill nitrosomas, Agro+, Super. U � Ammonium-Thio-Sulfate: Low p. H keep NH 4 from going to NH 3, short lived.

To Use or Not to Use � When less or not beneficial › Arid environments › Well drained soils that allow infiltration but have limited leaching

To Use or Not to Use � When more beneficial › Tile Drainage › Wet soils › Irrigated fields

Phosphorus � Chemically “Charged” � Binds with Iron, Aluminum, Calcium › Oklahoma Soils high in ALL of these. › Average down state Ca, 6000 lbs avail. � Phosphorus Fertilizer and the Soil › Common commercial P fertilizers are highly (≥ 90%) water soluble

Poly vs. ortho In general, P in dry fertilizers such as 18 -46 -0 and 11 -52 -0 P is orthophosphate. � P in common fluid fertilizers such as 10 -34 -0 and 7 -21 -7 is present as both orthophosphate & polyphosphate. � › Approximately 2/3 of the P is present in the Poly and The remainder is Ortho › Some fluids such as the 9 -18 -9 have all of the P as Ortho The effect of both forms of P on crop production has been evaluated in various field trials throughout the Corn Belt. � The results from a study with corn in Nebraska are summarized in the following table. �

The effect of polyphosphate and orthophosphate on corn yield Source: University of Nebraska ave of 5 sites; low P test P Source P 2 O 5 Applied polyphosphate orthophosphate lb/acre 15 30 45 - - - -bu/acre - - - - 124 134 142

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Summary from P � You should not base choice of fertilizers on orthophosphate or polyphosphate claims. � Buy the source that best fits your needs and is the cheapest per lb of nutrient.

P stabilizer Avail®, which is marketed as a phosphate enhancing product, contains the same active ingredient as Nutrisphere. The Avail activity is attributed to binding of calcium or iron ions in the soil normally bind p. � AI of Nutrisphere/Avail, the compound is highly negatively charged and would tend to bind with any compound with a positive charge, not distinguishing one ion over another. �

OK State Research Results

OK States Work � Avail Studies in Wheat (Not Published) › Arnall, 3 years 2 sites per year. No positive. � Agrotain in Wheat (Published) › Arnall, No positive yield responses › Edwards, 1 out of 2 yrs positive. � Slow release N’s. Wheat and › Just as good as UAN or Urea. Corn. � NUE Sorghum (Not Published, ongoing) › ESN, SUPERU, Agrotain › Banded UAN in 2” x 2” UAN+Agrotain Plus & UAN + Nutrisphere Caused Stand Problems.

Ok States Work � Southern Water Group (On table) AR, AL, FL, NM, NC, OK, TX There were few differences due to N fertilizer sources or additives for the soils, crops, or environmental conditions evaluated. � Nutrisphere®, Nitamin® and Agrotain® did not improve yields at any location for any crop where tested. Pre-plant incorporated ESN (as compared to urea) improved the corn yield at one site in Arkansas. When tested at two sites in Arkansas, ESN improved seedcotton yield at one site but produced yields equal to urea at the second site. � Preplant incorporated ESN® performed better than urea on corn in Arkansas and cotton in one of the two sites in Arkansas. The ESN® performed similarly or worse than UAN solution or urea in Alabama (corn), North Carolina (corn and wheat), Oklahoma (wheat) and Texas (grain sorghum). �

Peer Reviewed Pubs List on back table NPK. okstate. edu

Thank you!!! www. extensionnews. okstate. edu Brian Arnall 373 Ag Hall 405 -744 -1722 b. arnall@okstate. edu Presentation available @ www. npk. okstate. edu Twitter: @OSU_NPK You. Tube Channel: OSUNPK