Proceedings of the 2 nd Annual Nitrogen: Minnesota s Grand Challenge & Compelling Opportunity Conference Do not reproduce or redistribute without the written consent of author(s)
Anhydrous Ammonia, Soil, & CEC: Myths and Fred Vocasek Senior Lab Agronomist Servi Tech Laboratories CCA #01803 International Events Center, Rochester, MN 1
Fritz Haber Carl Bosch *Shepers. 2014. https://scisoc.confex.com/scisoc/2014am/videogateway.cgi/id/20444?recordingid=20444 International Events Center, Rochester, MN 2
hydrogen ion, H + hydroxl, OH water, H 2 O clay, OM ammonia, NH 3 NH 3 NH3 NH 3 NH 3 ammonium, NH 4 + NH 4 NH 4 NH 4 International Events Center, Rochester, MN 3
` affected by: rate per linear foot soil texture soil moisture International Events Center, Rochester, MN 4
sand silt clay Soil Textural Triangle 100 90 USDA classification Name Millimeters, mm Inches, in. 80 Sand 0.05-2.0 1 / 500 th - 1 / 13 th Clay % 70 60 50 40 30 20 10 silty clay silt clay silty clay loam silt loam clay loam loam sandy clay sandy clay loam sandy loam sand 0 0 10 20 30 40 50 60 70 80 90 100 Silt 0.002-0.05 1 / 12,000 th - 1 / 500 th Clay < 0.002 < 1 / 12,000 th 0.001 mm = 1 micron Sand % International Events Center, Rochester, MN 5
Soil clay particles (magnified) 1 micron = 0.001 mm 1/25,000 th inch International Events Center, Rochester, MN 6
exchangeable bases exchangeable acidity, estimated General texture CEC range, meq/100g Sands 3 5 Loamy sand 4 8 Sandy loams 6 12 Loams 15 20 Silt loams 15 25 Clay loams 15 25 Sandy clays 15 30 Sandy clay loams 15 30 Silty clay loams 20 35 Clays 25 50 Organic soils, mucks 50 100 (OM > 20%) International Events Center, Rochester, MN 7
bases, meq/100g 100 = % base saturation Balance the cations W.A. Albrecht, 1940 F.E. Bear, et. al. 1945 others... 1930 s 1940 s, 1950 s International Events Center, Rochester, MN 8
A Review of the Use of the Basic Cation Saturation Ratio and the Ideal Soil * Our examination of data from numerous studies... would suggest that, within the ranges commonly found in soils, the chemical, physical, and biological fertility of a soil is generally not influenced by the ratios of Ca, Mg, and K. Cation ratios have no direct impact on yield key = maintain sufficient supply of nutrient cations in crop root zone at optimum base cation ratios, may still have nutrient deficiency or ph concern * Kopittke & Menzies, 2007, Soil Sci. Soc. Am. J. 71:259 265 Fertilizer needed to increase saturation by 1% differs Potassium as K 2 O 432 1253 494 Magnesium as MgO 848 83 http://ianrpubs.unl.edu/live/ec155/build/ec155.pdf International Events Center, Rochester, MN 9
Myth: by Cecil Hagen, The Washington Farmer 1943, Mississippi Expt. Station/TVA International Events Center, Rochester, MN 10
Laboratory study, 1947 Purdue Univ. equivalent to: 4 inch depth 15 inch spacing 60 lb N/ac Air dry 600 lb N/ac Air dry Jackson & Chang. 1947. Agronomy Journal 39:623 633 Laboratory study, 1947 Purdue Univ. equivalent to: 4 inch depth 15 inch spacing 60 lb N/ac Field moist 600 lb N/ac Field moist Jackson & Chang. 1947. Agronomy Journal 39:623 633 International Events Center, Rochester, MN 11
How much anhydrous ammonia can different soils hold? General texture CEC range, meq/100g Sands 3 5 Loamy sand 4 8 Sandy loams 6 12 Loams 15 20 Silt loams 15 25 Clay loams 15 25 Sandy clays 15 30 Sandy clay loams 15 30 Silty clay loams 20 35 Clays 25 50 Organic soils, mucks (OM > 20%) 50 100 Estimated CEC, meq/100g 3% OM 2% OM 1% OM (2 OM%) + (0.5 clay%) = estimated CEC International Events Center, Rochester, MN 12
Estimated amount of nitrogen per acre retained by different soil textures 4 5 6 From study including 76 soils from Pacific Northwest Calculated ammonia retention: ppm N = (CEC * 95.8) + 153 multiplied by estimated ammonia retention diameter (if applied on 30 inch spacings) adapted from dat by Young. 1964. Soil Sci. Soc. Proc. 28:339 345 Rule of Thumb: If you can t smell it, you aren t losing it. International Events Center, Rochester, MN 13
If you can t smell it, you aren t losing it 1 qt liquid NH 3 = 1 lb N 10 ppm NH 3 13 in. Soil moisture affects ammonia retention DRY MOIST WET % AMMONIA LOSS % SOIL MOISTURE International Events Center, Rochester, MN 14
Apply anhydrous ammonia. Safe separation distance? free ammonia, NH 3 nitrite, NO 2 nitrate, NO 3 ammonium, NH 4 + Myth: International Events Center, Rochester, MN 15
Anhydrous Ammonia, Soil, & CEC: Myths and Net effect of anhydrous ammonia on the numbers of fungi, bacteria, and actinomycetes* + 8 million loamy fine sand 100 lb N/ac 16 inch spacing 3 3 4 million * Millions of organisms per gram of soil = ammonia treated soil numbers non treated soil numbers net effect Eno, C.F. and W.G. Blue. 1954. The effect of anhydrous ammonia on nitrification and the microbiological population in sandy soils. Soil Sci. Soc. Proc. 18:178 181. Myth: none NH3 urea UAN 34 0 0 Differences not statistically significant K State 20 year field study, three locations, 200 lb N/ac, silt loam, silty clay loam International Events Center, Rochester, MN 16
Changes in soil organic carbon after 15 years 5.5% OM cont. corn 4.9% OM corn/soy cont. soy 4.2% OM initial soil carbon level Hord silt loam, Nebr. center pivot irrigated 15 years: 1991 2005 after Varvel, 2008 Myth: International Events Center, Rochester, MN 17
Soil density, lb/cu.ft. K State 20 year field study three locations silt loam, silty clay loam 200 lb N/ac 2½ 5½ inch layer 8½ 11½ inch layer Kansas State Univ., Pub. C 625, The Effects of Nitrogen Fertilizer on Soil, 1991 International Events Center, Rochester, MN 18