Fertilizers Form Function Fertilizers Basic Definition Has a
Fertilizers: Form & Function
Fertilizers – Basic Definition • Has a guaranteed analysis. • This is the minimum level of fertilizer nutrients expressed as a percentage. • Also tells us the source of the fertilizer nutrients. • Contains fertilizer nutrients. • Not a growth amendment or stimulant.
Classes of Fertilizers • Soluble • Slow Release – Chemically Slow Release – Physically Slow Release – ‘Stabilized’ N Sources – Those that are Slow-Release via Mineralization (Organic) • Other fertilizers – bioenhanced, microbially mediated, etc. Those derived from proteins?
Soluble Fertilizers • • • Immediate nutrient release Rapid turfgrass response Possibility of turf burn Tend to be inexpensive Examples: urea, (NH 4)2 SO 4 Most often our foliar sources, too.
Relative color of hybrid bermudagrass all N sources applied at 1/2 lb N/M (2. 4 g N m-2)per month 8 Urea AS Control Relative Color (1 -9 scale) 7 6 5 4 3 2 0 20 40 60 80 100 120 Days after experiment start 140 160 180
Other Soluble N Sources • • Ammonium sulfate (21 -0 -0) Calcium nitrate Potassium nitrate (13 -0 -44) Sodium nitrate (16 -0 -0)
Establishment of Hybrid Bermudagrass as Affected by N Source Ca(NO 3)2 NH 4 NO 3 Day/Month/Year 7 -9 -02 7 -29 -02 8 -13 -02 shoots per cup cutter 76 a 127 b 147 a 74 a 7 -6 -04 88 a 90 a 137 a 7 -21 -04 96 a 109 a 145 a 8 -19 -04 98 a 100 a
Slow-Release Fertilizers • Physically slow-release – Slow release via a physical coating around a soluble prill – Technologies have been around since the 1950 s, others newer (80 s and 90 s) • SCU • PCU, resin-coat, multi-coat • Chemically slow-release – Slow release by their manufacturing method (homogeneous) – 1950 s – Ureaformaldehyde/Methylene urea – IBDU
Chemically Slow-Release • Slow release due to a chemical reaction. • Nitrogen must be made plant available by bonds being broken. • Methylene ureas (urea formaldehyde). • Isobutlyidene diurea (IBDU). • Slower, more consistent N release. • Higher cost than soluble.
(7. 8 g N m-2)
Physically Slow Release • Coated with wax, sulfur or plastic to make slow-release. • Typically urea, but also may be K 2 SO 4. • Consistent, slow N release. • Length of release varies with coating thickness and other coating characteristics.
Relative color of Tifway hybrid bermudagrass as affected by N source, Auburn, AL. Fertilizers applied on May 19 th at 1. 5 lb N/M (7. 4 g N m-2). 9 Urea Polyon Control relative color (1 -9 scale) 8 7 6 5 4 3 2 0 7 14 21 28 35 42 49 56 days after fertilizer application 63 70 77
6. 8 g N m-2 2 x 6. 8 g N 2 x 4. 9 g N 4 x
6. 8 g N m-2 2 x 6. 8 g N 2 x 4. 9 g N 4 x
There are MANY different types: Penn G-2 color as affected by slow-release N source, Farmlinks GC, 2007 9 relative color (1 - 9 scale) 8 7 Urea 46 Nitroform 38 6 Trikote 42 Poly. Mini 41 5 Reg. Poly 42 Control 4 3 0 1 2 3 4 5 6 7 8 weeks after fertilizer application 9 10
Estimated Days for N Release 45 90 120 180 days after application 1 Percent Nitrogen Release Traffic None P-value 7. 0 2. 6 0. 04 13. 0 6. 7 0. 09 6. 3 1. 9 0. 24 3. 2 0. 3 0. 97 %N release None Estimated Days for N Release Traffic 45 13 7. 8 0. 15 90 11 7. 5 0. 34 120 6. 3 5. 0 4. 8 4. 4 0. 44 0. 71 180 P-value 2016 Prill damage study, Auburn.
Total Percent N Volatilized by Source 50 % N Volatilized 45 40 35 30 25 20 15 10 5 0 Urea SCU Polyon Methx N Source AN Milorganite
‘Stabilized’ Nitrogen Fertilizers • Urea with the addition or either a nitrification inhibitor (dicyandiamide), urease inhibitor (N-(n-butyl) thiophosporic triamide), or both. • Inhibits the enzymes urease and ammonium mono-oxygenase.
Volatilization (Urease) Inhibitors • Maleic itaconic co-polymer – Nutrisphere-N® • Ca-Heteropolysacharides Cl and Ca. Aminoethylpiperazine Cl – NStay®, Stay-N® • Calcium polymer blend – NZone • N-(n-butyl) thiophosporic triamid- UMaxx, Uflexx, Hydrexx
Volatilization Loss of N to atmosphere as ammonia gas. Big issue in manure application. Common with urea or urea-based products. Irrigation lowers N loss. Lab Method
Passive Micrometerological Technique – Field Study 10 foot aluminum mast Wind vane Oxalic acid-coated tubes inserted perpendicular to mast at 5 heights
N volatilized as a percent of N applied Ammonia Volatilization as affected by N source, 10 week field study. N applied at 1. 5 lb N/M on July 20 2009 (7. 4 g N m-2). 20 Urea Polyon XCU Umaxx 18 16 14 12 10 8 6 4 2 0 0 1 2 3 4 5 6 weeks after N application 7 8 9 10
How to prevent volatilization losses? • Don’t use urea (still an issue on high p. H soils, however) • Water in • Slow-release sources • Foliar • Volatilization inhibitors
0 3. 2 mm 6. 4 mm 12. 7 mm 25. 4 mm
Nitrification Inhibitors • In agriculture, we try to slow this ammonium to nitrate conversion using nitrification inhibitors. • Have been around for 40 years, but are coming back into the market again with new products.
Nitrification – Conversion of ammonium into nitrate, done by nitrifying bacteria. Incubation study. Effect of addition of dicyandiamide. + inhibitor urea control Extractable soil ammonium + inhibitor control Extractable soil nitrate
Fertilizer
Urea versus Urea + additive 1 lb N/M 0. 8 lb N/M Never a significant difference between the two treatments.
Organic Fertilizers and Biofertilizers
Organic – at its simplest, it means that the product contains carbon. Organic Fertilizer - a material that is derived from plant or animal-based materials.
Let’s take a closer look at that…. Dissolved organic N (ppm) Microbial biomass N (ppm) Soil organic matter (%) Control 6. 49 + 3. 83 104 c 4. 51 b Organic (216) 3. 78 + 1. 20 134 a 4. 95 a Organic (216) + post-herb 1. 67 + 0. 03 128 ab 4. 55 b Mineral (219) 7. 07 + 2. 03 106 c 4. 44 b Mineral (98) + pre/post herb 4. 36 + 1. 77 100 c 4. 37 b Mineral (245) + pre/post herb + fung 4. 30 + 1. 44 110 c 4. 63 b Mineral (171) + pre/post herb + insect 4. 84 + 1. 32 107 c 4. 63 b October, 2004 data collection Long term application of organic fertilizers resulted in a significantly higher soil microbial biomass. Cheng et al. , 2008
Penn G-2 bentgrass putting green 9 N at 4. 9 g N m-2 (1 lb N/M) Relative Color (1 -9 scale) 8 7 6 5 4 Urea 3 Milorg 2 Sustane (4%N) Control 1 0 7 14 21 28 35 42 49 Days after Fertilization 56 63 70 77 84
Crystal Green • • Crystal Green is sustainably produced by Ostara using nutrient recovery technology that combines phosphorus, nitrogen, and magnesium into pure crystalline granules. Crystal Green is virtually water insoluble and releases only in response to organic acids produced by growing roots. Phosphorus content in wastewater can be reduced by recovering a portion of the phosphorous as a crystalline product called struvite. Struvite is relatively easy to dry and handle and shows potential as a slowrelease fertilizer. Struvite is the common name for magnesium ammonium phosphate hexahydrate (Mg. NH 4 PO 4 · 6(H 2 O)).
Percent establishment of Tifway hybrid bermudagrass as affected by P source. Auburn, AL, 2014. • Bermudagrass was sprigged on June 25 th 2014. • All P applied at 2 pounds P 2 O 5 per 1, 000 ft-2 (9. 8 g P 2 O 5 m-2) 1 wk prior to sprigging.
(9. 8 g P 2 O 5 m-2)
(9. 8 g P 2 O 5 m-2)
guertea@auburn. edu
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