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Nitrification Inhibitors andControlled Release FertilizersRichard SmithUC Cooperative Extension, Monterey County
Why Nitrogen FertilizerTechnology? To impprove Nitroggen UseEfficiency - NUE Given that nitrate is so readilyleachable, the use of technologiesthhat can redduce thhe pooll offnitrate, but still make N availablein adequate quantities and at theright timing for crop growth couldimprove NUE
Nitrification Inhibitorsi'NlltOJIHI SldlllmIw:;AGRNitrapyrin (not registered onvegetables)Urease inhibitor DCD nitrification inhibitorETEC DMPP (not available in the US)Nitrapyrin – low volatilityfformulationl i (not(registeredid onvegetables)
Nitrification InhibitorsNH4 NO3- These chemicals disrupt theactivity of Nitrosomonas andNitrobacter bacteria which areresponsible for nitrification ofammonium to nitrate If we can keep more of theN as ammonium,, thereappliedppwould be less leaching losses
Impact of Dicyandiamide (DCD)on NiNitrate Leachihing60 .so il 150"'CGJ.c --.ura C 40-,z GJE:Im 0I[:] .so il 1 DCD so il 2 .so il 2 DCD300 ,z-.raI t1D20E. .100246Weeks of incubationTim Hartz 2011
Controlled Release FertilizersDuration. 5cantro II @d-Ralease Fertilizer ----1Coated urea prills (polyurethaneothercoatings)I and-Sure ----- ---IILChains or ringgs of urea molecules(can be foliar applied)
Controlled Release Fertilizerone example The diffusion of nitrateout of the prill iscontrolled by thethickness of the coatingand environmentalconditions (temperature) The coating meters thereleased nitrate ratherthan allowing the releaseof a large quantity thatwould build up a nitratepoolUreaPolyurethane coatedUrea
Other slow release fertilizersCalcium cyanamidIL IAnd many others9 :: :::::::::::: ilDry organic materials:ILmeat, fish, bone, feather meals
Factors Affecting NUE Irrigation management The key driver in nitrate losses Shallow rooted crops Narrow zone where the nitrate mustremain in order to be used by the crop Short‐term, high nitrogen demand Difficult to supply large quantities of N fora short period of time without sufferinggsome inefficiency in nitrate use
Irrigation Impact on NitrogenUse Efficiency One inch ofleached watercarries 23 lbs ofN/A @ 100 ppm nitrateN in the soilsolution
Root Distribution of Lettuce - 60 days oldTwo feetBed Width (inches)Drip linePlant Line5152025Weaver and Brunner, 192720250102030405060702Deepth (inches)10Drip linePlant Line15Root Nummber / 100 cm510
Recent Trials Evaluating NitrogenF tili TechnologyFertilizerT h lin Lettuce Production
2011 Lettuce Yield (T/A)Nitrification Inhibitor Trial10150100100 AgrotainLbs N/A100 4%DCD100 8%DCD
2010 Nitrification Inhibitor Impact onNitrate in Leachate 50---0--D------- :r---NO3-NN mg N l-140······· · ········.10 lbs N/A160 lbs N/A60 lbs N/A110 lbs N/A60 lbs N/A Agrotain110 lbs N/A Agrotain302010035404550sDAGW556065
DCD applied in drip is dilutedin a greater volume of soiland may affect its efficacy
2012 Lettuce Fertilizer TrialTi lant& tiongHarvestAprilJune verIrrigation
2012 Lettuce Fertilizer TrialTreatmentTotal N/A/Untreated25Standard155Moderate105Agrotain Plus105G77105DMPP105D45105D45 sidedress155D45155N‐Sure105 Standard received 65 lbsN/A and all moderatetreatments received 40 lbsN/A in two fertigationswith UN32 on 29 & 41 daysafter planting D45 sidedress was treatedwith 50 lbs N/A on 1stfertigation N‐Sure was applied as a50:50 mix with UN32 inboth fertigations
Injection of fertilizer treatments: Each treatment had its own main Treatments were injected intothe ports and each main deliveredthe N to the associated beds
Excellent Response toF tiliFertilizerUntreated
Yield Evaluation35.0dd30.0ddccd25 025.0bTonss/A20.015.0aaa10.05.00.0Untreated155 st105 mod105 Agrotain105 G77105 DMPPD45 105D45 155 SDD45 155N‐Sure
Nitrogen Uptake by Lettuceat Harvest120.0eeed100.0ccLbs N/A80.0b60.040.0aaa20.00.0Untreated155 st105 mod105 105 G77Agrotain105 DMPPD45 105D45 155 D45 155SDN‐Sure
AppliedppN/Uptake/ pN RatioDoes not account for soil N or leaching losses3.02.52.0151.51.00.50.0Untreated155 st105 mod105 Agrotain105 G77105 DMPPD45 105D45 155 SDD45 155N‐Sure
Irrigation Events in Relation toCrop ET from Thinning to Harvestt.601,,.401,,.20 App ied water1,,.00 Crop IET0 ,.800,. 600,.400 ,.200 ,.00
Nitrate‐NNitrateN in Soil on Four Dates45.040.035.0.Untreated155.105.-30.025.0-- 105 Agrotain105 G77105 DMPP20.0- - - D45 105D45 155 SD15.0D45 155.N‐Sure10.05.00.0July 17July 31August 7August 22
Nitrate‐N at 2 – 3 Feet in SoilAAugustt 15Average at start of trial (July 2) 1.6 ppm20.0bb18.0b16.0b14 rdModerateAgrotainPlusG77DMPPD45 105D45 SDD45 155Nsure
Irrigation Events in Relation toCrop ET from Thinning to Harvestt.601,,.401,,.20 App ied water1,,.00 Crop IET0 ,.800,. 600,.400 ,.200 ,.00
Nitrate‐N at 2 ‐ 3 Feet in SoilAugusst 7DMPP0.0UntreatedStandardModerateD45 105D45 SDD45 155Nsure
Summary All nitrogen technologies showedgreat promise for improving nitrogenuse efficiency Moderate level of N fertilization hadimproved yield with Agrotian Plus,DMPP, D45 and N-Sure under theconditions in this trial
Summary Given the great NUE of the CRF,the rates should be examined tosee if we can reduce the loss ofnitrate beyond the rootzoneobserved in this trial
Summary The use of these technologiesdoes not preclude the need forgood irrigation management
in a greater volume of soil and may affect its efficacy . 2012 Lettuce Fertilizer Trial . Ti li Timeline Deep Deep Deep Soil Soil Soil . Mowed. Apply; nd; Plant Germ Thin 1; st; 2 Harvest CC; CRF &anticrustant: Water: . Microsoft PowerPoint - Smith, Richard.ppt [Compatibility Mode]
