The Future of Controlled-Release Fertilizers International Nitrogen Conference Oct 1-5, 2007 Costa do Sauipe, Brazil Dr. Alan Blaylock Sr. Agronomist Agrium U.S. Inc and Agrium Advanced Technologies
The Future of Controlled-Release Fertilizers Overview of products and modes of action Reducing N losses Improving N-use efficiency Maintaining/increasing productivity Managing risk The future
Controlled-Release and Enhanced-Efficiency Fertilizers Controlled-release is a subset of a larger group of fertilizers being called enhanced-efficiency fertilizers Old and new products being viewed with new interest
Many Products Different Modes of Action Inhibitors and stabilizers Uncoated, slowly available compounds; synthetic organic compounds Coated water-soluble fertilizers www.fertilizer.org/ifa/news/2005_17.asp Jim Robbins, Univ of Arkansas
Inhibitors and Stabilizers Reduce loss by slowing conversion of N sources to forms that can be lost Protection time days to a few weeks Not true slow release Examples: Agrotain (NBPT), N-Serve (nitrapyrin), DCD, Super U, Super N (Agrotain Plus), Nutrisphere N. Provide a specific benefit for a specific amount of time If you have conditions for the loss addressed by the product for the effective period of the product, the benefit is realized.
Uncoated, Slowly Available Compounds Protect N by delaying N availability Generally rely on biochemical decomposition Protection time typically weeks to months Release rate determined by Chemical structure (resistance to breakdown) Molecular weight/degree of polymerization Environmental conditions Release slow but generally uncontrolled
Uncoated Slow Release Fertilizers Urea formaldehyde (UF) & methylene urea (MU) Isobutylidene diurea (IBDU) Natural organics Still largely horticultural products professional turf, etc. Some new products on the market for ag Nitamin, Nfusion,
Coated Water-Soluble Fertilizers Coatings applied to conventional fertilizers Physical barrier against nutrient exposure Sulfur- and polymer-coated urea
Sulfur-Coated Urea Insoluble sulfur coating + protective overcoat applied to urea N availability depends primarily on destruction of coating Physical breakage Biological oxidation Diffusion Release rate determined by Thickness of coating Environmental conditions Release slow but uncontrolled
Polymer-Coated Fertilizers Polymer coatings applied to soluble fertilizer Polyurethane, polyolefin Release by diffusion through coating Release rate determined by Polymer chemistry, thickness, coating process Temperature Release can be highly controlled and can be designed to match plant uptake. Examples: Osmocote, Polyon, Duration, ESN
Corn Growth and N-Uptake Seasonal Nitrogen Uptake, % 100 75 50 25 0 Early Growth Sidedress Rapid Growth Maturing May June July Aug Sept Late Loss 80% of requirement after V8-10
Reducing N Losses Controlling N transformations to slow conversion to a susceptible form Reducing loss by physically protecting soluble N forms from exposure to N-loss mechanisms Nitrate leaching N 2 O emissions Ammonia volatilization
N Source and N Leaching Losses Winter Wheat, Ohio, 2003 Total cumulative N loss (lbs N/ac) Total monthly precip. (in) 10 8 6 4 2 0 8 6 4 2 0 N applied April 4 at 30 or 45 lbs N/ac on winter wheat Feb Mar Apr May Jun Jul Aug control UAN 45 Urea 45 ESN 30 ESN 45 Source: Dr. R. Islam, The Ohio State Univ, 2003. Inorganic N in leachate from 100- x 30-foot lysimeters. Calculated from total water volume and N concentration.
Nitrate Leaching in Potato Production, Minnesota, 2004 Nitrate-N (mg N/l) 100 80 60 40 20 0 Nitrate concentration in suction lysimeters Conventional N program (fertigation 8x thru pivot) ESN pre-plant + one fertigation 7/22 10-May 25-May 2-Jun 9-Jun 18-Jun 28-Jun Source: Dr. Carl Rosen, Univ of Minnesota. Sampling date 7-Jul 15-Jul 22-Jul 2-Aug
N 2 O Emissions (May 1 to June 30, 2006) Corn - Woodslee, ON, 2006 Seasonal N 2 O emissions (kg N ha -1 ) 1.0 0.8 0.6 0.4 0.2 Regular Urea Coated Urea 0.0 CT NT ZT CT NT ZT Preplant N application Sidedress N Application Corn following wheat Source: C Drury, AAFC, Harrow, ON
N Source and Ammonia Loss Laboratory Incubation Cumulative Ammonia Loss (% of applied) 60 50 40 30 20 10 0 0 5 10 15 20 Days After Treatment Urea UAN Urea+NBPT UAN+NBPT UAN+NBPT+DCD UAN+CaTs ESN Source: Dr. W. Thornberry, Sturgis, KY; Dr. S. Ebelhar, Univ of Illinois Laboratory incubation
N Source and Ammonia Volatilization Washington, 2007 Cmulative Ammonia Loss (mmols NH 3 x 1000) 80 70 60 50 40 30 20 10 0 Control ESN (150 lbs N/ac) Urea (150 lbs N/ac) 0-3 4-7 8-11 12-15 16-19 Days After Application Field study; spring top-dress application on winter wheat Source: R Koenig, Washington State Univ
Irrigated Corn Yield and N Recovery Corn Yield (bu/acre) 220 200 180 160 140 120 100 19 41 43 Urea AS AS+NI ESN Urea AS ESN 44 35 50 49 Corn Yield Apparent N Recovery 60 50 40 30 20 10 0 Apparent N Recovery (% of applied fertilizer N) Pre-plant Side-dress/split Apparent N recovery = N uptake in control (no N) - N uptake in treatment fertilizer N rate x 100. Average control yield = 103 bu/acre, control N uptake = 67 lb N/acre. NI=Nitrification inhibitor, DCD Source: L Bundy, Univ of Wisconsin
Corn Response to Pre-plant Urea and UAN Compiled Data from US Corn Belt Studies 100 Relative Corn Yield (% of maximum) 90 80 70 60 50 0 40 80 120 160 200 240 N Rate (lbs/ac) Plateau yield of urea and UAN (93.1%) at 200 lbs N/ac Data compiled from studies in US Corn Belt studies comparing pre-plant urea and UAN with pre-plant ESN.
Corn Response to Pre-plant ESN Combined Data from US Corn Belt Studies 100 Relative Corn Yield (% of maximum) 90 80 70 60 50 ESN produced plateau yield of urea & UAN (93.1%) at 118 lbs N/acre (vs 200) 0 40 80 120 160 200 240 N Rate (lbs/ac) Plateau yield of ESN (97.4%) at 187 lbs N/ac Data compiled from studies in US Corn Belt studies comparing pre-plant urea and UAN with pre-plant ESN.
Managing Risk N Source & Timing Winter Wheat, Princeton, KY, 2006 Wheat Yield (bu/ac) 90 80 70 60 50 40 30 20 10 0 Planting 15-Jan 1-Feb 15-Feb 1-Mar 15-Mar 1-Apr Application Date 100 Urea 100 ESN Source: Dr. G. Schwab, Univ of Kentucky
The Past and Present If enhanced-efficiency fertilizers can do all this, why are the not used more frequently? The past: Wide-spread use has largely been limited by cost: expensive products not viable for low value commodity crops. Recognition of traditional BMPs while new technologies that may be as good as or better not yet recognized in policy or practice.
The Future (the Present?) New, lower cost products Higher N prices put premium on efficiency Greater awareness of environmental impact Higher crop prices improve economic viable Government incentive programs
The Future What Will Aid Adoption Research and education Understanding how different modes of action with loss mechanisms Understanding where and when benefits are observed Emphasize need to match mode of action to N-loss mechanism and cropping system Target right product to specific N loss mechanism with consideration of soil & weather conditions, cropping system, equipment, infrastructure, etc Integrate with other technologies
Variable-Source N Fertilization Greenley, MO, 2005 Summit Sideslope Low-lying Corn yield (bu/acre) 125 100 75 50 N applied before planting (mid-april) at 150 lbs N/ac 94 94 93 79 74 Source: Drs. P. Motavalli, K. Nelson, Missouri, 2005. 117 Urea ESN
What Drives the Grower s Decision Drivers are economics, convenience, simplicity, risk Economics are usually foremost Nitrogen BMPs compete with other practices for time, labor, equipment, fuel, etc. Controlled-release fertilizer technologies can substitute for time, labor, equipment - making multiple applications - and achieve the same result with less risk. Cost and benefit There must be a benefit, real or perceived, the grower wants that justifies the cost. Growers will pay a higher price if the benefits are sufficient and sufficiently consistent.
Enhanced-Efficiency Fertilizers CAN Enhance Efficiency Reduced losses to water and air, increased plant uptake, improved productivity and profitability when matched with appropriate environment Simplified N management with less risk for producers Enhanced efficiency fertilizer technologies will become and are now becoming a larger part of nitrogen management tactics. The future is indeed bright for these technologies.
Thank you for your time Alan Blaylock 303-804-4479 ablayloc@agrium.com www.agrium.com