Supercharging your P fertilizer Does it Work? Cynthia Grant, Cynthia.grant@agr.gc.ca
Phosphorus Phosphorus is critical for crop growth Structural component of nucleotides, nucleic acids and phospholipids. Essential for all energy reactions Needed for all growth processes Promotes root development, tillering, early flowering, seed production, and uniform ripening. P fertilizer is a major input for crop production on the Canadian prairies Low P recovery is a major economic and environmental concern
How Much Phosphorus is Needed by a Crop? A 45 bu/acre spring wheat crop removes about 24 lb P 2 O 5 per acre About 10 lb more taken up but recycled in residue Total of about 34 lb needed for growth 40 bu/acre canola removes 38 and needs around 58 lb for growth Without an adequate P supply, crop yield will be reduced -input and off-take should be balanced over time to avoid excess or depletion -not all crop requirement has to come from fertilizer in each year
Plants Access P from Soil Solution Fertilizer additions make up the difference between crop demand and soil supply Soil solution phosphorus HPO 4-2 H 2 PO 4-2
Products and practices that attempt to improve P use efficiency Banding P near the seed Use of more crop available forms Fluids versus dry Orthophosphates versus polyphosphates Reduce soil reactions Avail Release P gradually to match plant uptake Coated MAP Fungi that mobilize P in rhizosphere Provide Penicillium bilaii Fungi that improve plant access to P Mycorrhizae 5
How efficiently is P fertilizer used in wheat systems on the Canadian prairies? It is estimated the P use efficiency in the year of application is generally less than 30% What happens to the other 70%? Lost by run-off or erosion? Converted to other forms of varying solubility? Incorporated into the soil organic matter or microbial biomass? Used by subsequent crops? Can we use our P fertilizers more efficiently?
On a long-term basis, crop removal and replacement of P seem to be relatively well-balanced 140,000 120,000 Manitoba 1965-2006 P2O5 (tonnes) 100,000 80,000 60,000 40,000 P Removed Indicates about 80% recovery over time 20,000 P Added 0 1965 1970 1975 1980 1985 Timing of supply is important for crop yield response 1990 1995 2000 2005 Source: Johnston 2006
Soil P Reactions Reduce P Availability Plant Uptake Phosphate Fertilizer Soil Solution P Lower Availability Primary Minerals (Apatite) Mineral Surfaces Secondary Ca and Mg or Fe and Al phosphates
Principles of Phosphorus Nutrition that Affect Fertilizer Management Choices Soil will supply P to the crop Fertilizer tops up soil supply for optimum yield P availability varies with environmental conditions P is needed early in growth Plants must have adequate supply in first 3-6 weeks Soil supply may be too low early in the season Need to apply starter at or before seeding P is not very mobile Ties up with Ca, Mg, Al and Fe Doesn t move far in the soil Roots must intercept P since P won t move to roots
Phosphorus is Relatively Immobile in the Soil Has important effect on P management decisions
Phosphorus Should be Banded Banding slows tie-up of P in soil Having ammonium N in the band slows reactions further MAP, DAP and APP are effective P sources because they contain ammonium Adding urea to MAP bands increases fertilizer P uptake when fertilizer is banded away from seed However, excess N can delay P uptake due to band toxicity
Phosphorus Should be Banded Some plant roots proliferate in bands Ammonium in the band may also increase root proliferation Uptake increases with P concentration and rooting Fertilizer bands provide high concentration More roots in the band increase uptake
Banding P Near the Seed-Row Ensures that Roots Will Contact the P Granule Early in Growth Broadcast Banded At 25 Kg P 2 O 5 /Ha and 18 cm row spacing have a granule every 2.3 cm (11-55-0) The large difference between banded and broadcast applications is POSITION Courtesy Geza Racz
Banding P Near Seed is Most Important With Low soil P levels Restricted rooting Compaction Tillage pans Cool soil conditions Solubility, mobility, rooting Early seeding
Fall band 70-30-10-10 on whole field +10 lb/ac Seed row P 2 O 5 No starter P Pop-Up Effect from Seed Row P Photo: Aaron Baldwin, Cargill
Grain Yield (T/ha) Banding Reduces the Rate of P Needed 3.0 2.5 Broadcast Banded 20 band was as good as 80 broadcast 2.0 1.5 1.0 0 10 20 40 80 Phosphate (kg/ha) Westco Training Manual
Low P Mobility Limits How Much You Can Reduce P Application Rates Must have a high enough rate that each seedling can reach granule (or droplet) during early growth Reducing rate below about 15-20 lb/acre may restrict availability Distribution is affected by row spacing and band width Greater the seed-bed utilization, the wider apart the granules are spaced May need higher rate with higher seed-bed utilization
Dry Fertilizer Material Wheat - 7 rows, 5 lb/a P2O5 10 lb/a MAP fertilizer 7.6 between MAP particles Wheat - 7 rows, 10 lb/a P2O5 19 lb/a MAP fertilizer 3.8 between MAP particles
Dry Fertilizer Material Wheat - 7 rows, 15 lb/a P2O5 29 lb/a MAP fertilizer 2.5 between MAP particles Wheat - 7 rows, 20 lb/a P2O5 38 lb/a MAP fertilizer 1.9 between MAP particles
Liquid Fertilizer Material Wheat 7 rows, 5 lb/a P2O5 1.25 gallons/acre 10-34-0 11.2 between drops of fertilizer Wheat 7 rows, 10 lb/a P2O5 2.5 gallons/acre 10-34-0 5.9 between drops of fertilizer
Liquid Fertilizer Material Wheat 7 rows, 15 lb/a P2O5 3.75 gallons/acre 10-34-0 3.7 between drops of fertilizer Wheat 7 rows, 20 lb/a P2O5 5.0 gallons/acre 10-34-0 2.8 between drops of fertilizer
Can different formulations improve P availability? Monoammonium phosphate is the standard fertilizer source for the prairies Ammonium in formulation enhances efficiency Ammonium polyphosphate is standard fluid form Other novel formulations include: Fluid orthophosphates such as Alpine Avail additive Polymer coated MAP
Fluids Versus Dry Under highly calcareous conditions in Australia, fluid forms of P are more available than dry Water moving toward granule carries Ca Ca precipitates P and leads to small reaction zone Fluid forms increase reaction zone and allow greater root uptake Similar benefit has not shown up in tests in Manitoba
There was no difference between dry MAP and fluid APP in wheat yield over three years at two sites near Brandon Similar results in previous studies by Racz and in later studies on wheat and soybean Soils are much less calcareous than the 70% calcium carbonate in the Australian trials
Orthophosphates versus Polyphosphates Polyphosphates are chains of orthophosphates Most polyphosphate fertilizers still have 40-60% of the phosphate in the orthophosphate form Polyphosphate converts to orthophosphate in soils rapidly Half usually is converted within a week, Conversion may be slower if soils are cool and dry Generally no difference in effectiveness under field conditions http://www.extension.umn.edu/distribution/ cropsystems/dc6288.html
Grain yield, bu/acre In studies by Tom Jensen at Brandon, 10-34-0 and MAP performed as well or better than enhanced P products (Average of 8, 16 and 32 kg ha -1 phosphate rates) 42 41 40 39 38 41.2 39.2 a 38.2 38.1 b 37.2 38.5 ns 38.0 37 36 35.7 35 34 33 32 10-34-0 Simplot 7-25-6-4 MAP or 11-52-0 Omex 10-34- 0 plus TPA Alpine 6-22-4 Alpine 6-24-6 AVAIL No AVAIL
Some Enhanced Efficiency P Fertilizers Being Evaluated Avail Maleic Itaconic Copolymer Similar technology to Nutrisphere Complexes Ca, Mg, Fe and Al Reduces fixation of P Limited data under prairie conditions
Grain yield, bu/acre In studies by Tom Jensen at Brandon, yield was similar with MAP alone or treated with Avail a 42 41.2 b 41 ns 40 39 39.2 38.2 38.1 38.5 38.0 38 37.2 37 36 35.7 35 34 33 32 10-34-0 Simplot 7-25-6-4 MAP or 11-52-0 Omex 10-34- 0 plus TPA Alpine 6-22-4 Alpine 6-24-6 AVAIL No AVAIL
Grain yield, bu/acre In wheat on the prairies, yield was similar if MAP was applied with or without Avail 34 32 30 - Avail + Avail 28 26 24 22 0 10 20 30 40 Wheat (6 site-years) Phophorus rate, lb P 2 O 5 /acre Karamanos
Potato Yield (cwt/acre) Application of Avail-treated MAP produced the same potato yield as side-banded MAP Portage and Carberry 2007 to 2009 420 410 400 390 380 370 360 f e abc ab bc de Control Sideband 20 Sideband 40 Sideband 80 Avail 40 Broadcast 40 350 Gaia Consulting
Avail did not improve grain yield over MAP over three years at two sites near Brandon No difference among treatments All products performed the same if banded
Coated Enhanced Efficiency P Fertilizer is Being Evaluated Polymer coated monoammonium phosphate Same technology as ESN MAP is gradually released into soil solution Matching release to crop uptake should reduce fixation Can also reduce risk of seedling damage Limited testing so far
Neither the coated MAP nor the Avail improved grain yield over MAP or APP over three years at two sites near Brandon No difference among treatments All products performed the same if banded
Novel formulations have not shown yield benefit in most independent studies Fluids, MAP, orthophosphate and polyphosphates, Avail-treated and coated products performs similarly Important to band an adequate amount near seed-row Ensure P is available early in the growing season Balance P rate with removal over time to avoid depletion 34
What about the microbial products Two major products sold in western Canada Provide (Jumpstart and part of Tagteam) Mycorrhizal inoculants 35
Provide is a microbial inoculant Penicillium bilaii (also classified as P. bilaji and P. bilaiae) is a fungi that colonizes the rhizosphere Effective in solubilizing phosphorus (P) under controlled conditions Under field conditions, results have been mixed 36
Grain Yield (bu acre -1 ) On P responsive sites with durum wheat, Provide did not increase yield as compared to the untreated control at nine site-years in Manitoba and Alberta Adding Provide alone was equal to the untreated control Adding Provide plus 10 lb of phosphate gave yield response of about ½ of applying 20 lb of phosphate Significant yield increase with P but no significant benefit of provide 60 50 40 30 20 Control Provide alone Provide + 10 lb P 20 lb P 40 lb P Mean Minnedosa Grant et al. (2002)
Grain Yield (bu acre -1 ) Flax Yield Did Not Respond to Either Side-banded P or Provide in Nine Site-Years in Manitoba 35 30 25 20 15 10 5 0 Control 20 P Provide Brandon Minnedosa Rosebank
Wheat Yield (Bu/acre) Effect of P. bilaii and P fertilizer on wheat and barley barley grain yield Barley Yield (Bu/acre) 60 47 site years 20 site years 160 55 140 50 120 45 40 P alone P + P.bilaii 100 80 P alone P + P.bilaii 35 0 9 18 27 60 0 9 18 27 P Rate (kg/ha) P Rate (kg/ha) Karamanos
Mycorrhizal Association May Improve P Availability Mycorrhizae are an association between plant roots and a fungus Especially important for flax and corn Do not occur with canola or sugar beet Mycelium grows into the soil and increases area mined for nutrients Fungi gives nutrients to plant and plant gives sugars to the fungi Mycorrhizae are reduced by: Tillage Summer fallow P fertilization Following a nonmycorrhizal crop Plant Root
Benefit of Inoculation with Mycorrhizae Uncertain Inoculation with mycorrhizae not widely tested in field conditions Native mycorrhizae exist naturally in soils Inoculation may not be needed under many conditions Some crops are more dependant on mycorrhizae Flax or corn versus wheat Crop pays mycorrhizae with photosynthate If cost is greater than benefit, AM may decrease yield
-Colonization- % In nine site-years in Manitoba and Alberta colonization in wheat roots was increased by inoculation and reduced by P 30 25 20 15 * * * 10 5 0 Lacombe MCDC Maziers P Fertilizer Control Myc
Biomass Yield (T ha -2 ) Biomass at Six Weeks Tended to Decrease with Mycorrhizal Inoculant 1.6 ** 1.2 0.8 0.4 Control P Alone Mycorrhiza Mycorrhiza + P 0.0 Lacombe MCDC Maziers
Biomass yield at heading also tended to decrease with inoculation *
Mycorrhizal Inoculation Did Not Affect Wheat Grain Yield in Nine Site Years in Manitoba and Alberta
Grain Yield (bu acre -1 ) Inoculant tended to reduce grain yield at Philips in 2005 25 No Myc. Myc 20 15 Yield was higher with P fertilizer than inoculant alone Grain yield was reduced at Philips when inoculant was added with fertilizer 10 Control MAP SB CRP SB APP SB APP Drib.
Effect of mycorrhizal inoculation Mycorrhizal inoculation increased colonization Tended to decrease early biomass production No benefit on final grain yield Sometimes led to a small decrease in yield Mycorrhizae may cost wheat more than they contribute Need more information on other crops Effect may differ with flax
Summary P use efficiency in the year of application can be low 25 to 30% P reacts in the soil to forms that are less available than original fertilizer However plants can still access this P in following years 48
Summary Banding starter P placed close to the seed is important to optimize crop yield Cutting rate too low may not place P close to each seed Little difference between MAP and other new formulations under Manitoba conditions Fluids vs dry Orthophosphates vs polyphosphates Avail treatments Polymer coating 49
Summary Provide does not appear to be highly beneficial under field conditions Inoculation with mycorrhizal spores can increase colonization in wheat Does not lead to yield increase May decrease yield under some conditions Inoculation needs more testing with mycorrhizaldependent crops like flax 50
Summary Crop removal of P is fairly well balanced with P addition in non-manured fields P use efficiency may be higher than we think Cutting application rates to less than crop removal may not be desirable Too little P for plant roots to physically access Long-term depletion of soil P Crop productivity is lower on P depleted soils Band an available form of P near the seed row at rates that reflect crop removal over the cropping sequence 51
Thank You For your Attention