Nitrification Inhibitors and Controlled Release Fertilizers · PDF fileNitrification...
Transcript of Nitrification Inhibitors and Controlled Release Fertilizers · PDF fileNitrification...
Nitrification Inhibitors and Controlled Release Fertilizers
Richard SmithUC Cooperative Extension, Monterey County
Why Nitrogen Fertilizer Technology?Technology?
• To improve Nitrogen Use p gEfficiency - NUE
• Given that nitrate is so readily• Given that nitrate is so readily leachable, the use of technologies h d h l fthat can reduce the pool of
nitrate, but still make N available in adequate quantities and at the right timing for crop growth couldright timing for crop growth could improve NUE
Nitrification Inhibitors
Nitrapyrin (not registered on vegetables)
Urease inhibitor + DCD nitrification inhibitor
DMPP (not available in the US) Nitrapyrin – low volatility f l ti ( t i t dformulation (not registered on vegetables)
Nitrification Inhibitors
NH4+ NO3-
• These chemicals disrupt the activity of Nitrosomonas andactivity of Nitrosomonas and Nitrobacter bacteria which are responsible for nitrification ofresponsible for nitrification of ammonium to nitrate
• If we can keep more of the applied N as ammonium, there app ed as a o u , t e ewould be less leaching losses
Impact of Dicyandiamide (DCD)Ni L hion Nitrate Leaching
Tim Hartz 2011
Controlled Release FertilizersCo t o ed e ease e t e s
Coated urea prills (polyurethaneand other coatings)
Chains or rings of urea moleculesg(can be foliar applied)
Controlled Release Fertilizerone exampleone example
• The diffusion of nitrate out of the prill is pcontrolled by the thickness of the coating and environmental conditions (temperature)
• The coating meters the released nitrate rather than allowing the release
Urea Polyurethane coatedUreathan allowing the release
of a large quantity that would build up a nitrate
Urea
would build up a nitratepool
Other slow release fertilizersOt e s o e ease e t e s
Calcium cyanamid Dry organic materials:meat, fish, bone, feather meals
And many othersAnd many others
Factors Affecting NUE• Irrigation management The key driver in nitrate losses
• Shallow rooted cropsShallow rooted crops Narrow zone where the nitrate must remain in order to be used by the cropremain in order to be used by the crop
• Short‐term, high nitrogen demand Difficult to supply large quantities of N for a short period of time without suffering p gsome inefficiency in nitrate use
Irrigation Impact on Nitrogen Use Efficiency
• One inch of leached waterleached water carries 23 lbs of N/AN/A @ 100 ppm nitrate-
N in the soilN in the soil solution
Root Distribution of Lettuce - 60 days old
Two feetBed Width (inches)
5 10 15 20 25
5 01020
Plant Line Plant LineDrip lineDrip line
Root N
um
Two feet
epth
(inc
hes)
10
15
304050 60 70
mber / 100 cm
2
De
20
25
Weaver and Brunner, 1927
Recent Trials Evaluating Nitrogen F tili T h lFertilizer Technologyin Lettuce Production
2011 Lettuce Yield (T/A) Nitrification Inhibitor TrialNitrification Inhibitor Trial
Lbs N/A
2010 Nitrification Inhibitor Impact on Nitrate in Leachate
40
50 10 lbs N/A 160 lbs N/A 60 lbs N/A 110 lbs N/A 60 lbs N/A+Agrotain
N m
g N
l-1
30
60 lbs N/A+Agrotain 110 lbs N/A+Agrotain
NO
3-N
10
20
35 40 45 50 55 60 650
10
DAGW
35 40 45 50 55 60 65
s
DCD applied in drip is dilutedin a greater volume of soiland may affect its efficacy
2012 Lettuce Fertilizer TrialTi liTimeline
MowedCC
ApplyCRF
Plant & anticrustant
GermWater
Thin 1st
fertigation2nd
fertigationHarvest
Deep Soil
Deep Soil
Deep Soil
g g
April June 21 June26
June29
July 19
July 27
Aug8
Aug 29
Over Irrigation
Over Irrigation
2012 Lettuce Fertilizer Trial2012 Lettuce Fertilizer Trial
• Standard received 65 lbs Treatment Total N/AN/A and all moderate treatments received 40 lbs N/A in two fertigations
/Untreated 25Standard 155
N/A in two fertigations with UN32 on 29 & 41 days after planting
Moderate 105Agrotain Plus 105G77 105 • D45+sidedress was treated
with 50 lbs N/A on 1st
fertigation
G77 105DMPP 105D45 105 fertigation
• N‐Sure was applied as a 50:50 mix with UN32 in
D45 105D45 + sidedress 155D45 155
both fertigationsN‐Sure 105
Injection of fertilizer treatments:• Each treatment had its own main• Treatments were injected into the ports and each main delivered the N to the associated beds
Excellent Response to F tiliFertilizer
Untreated Standard
Yield EvaluationYield Evaluation35.0
25 0
30.0 d c cd
d d d
20.0
25.0
b
s/A
10.0
15.0a a a
Tons
5.0
0.0Untreated 155 st 105 mod 105 +
Agrotain105 + G77 105 + DMPP D45 105 D45 155 SD D45 155 N‐Sure
Nitrogen Uptake by Lettuce at Harvest
120.0
ee e
100.0 d
c
e
c
60.0
80.0
bN/A
40.0a a aLb
s
20.0
0.0
Untreated 155 st 105 mod 105 + Agrotain
105 + G77 105 + DMPP
D45 105 D45 155 SD
D45 155 N‐Sure
Applied N/Uptake N Ratiopp / pDoes not account for soil N or leaching losses
3.0
2.5
1 5
2.0
1.0
1.5
0.5
0.0Untreated 155 st 105 mod 105 +
Agrotain105 + G77 105 + DMPP D45 105 D45 155 SD D45 155 N‐Sure
Irrigation Events in Relation to Crop ET from Thinning to Harvest
Nitrate‐N in Soil on Four DatesNitrate N in Soil on Four Dates
40.0
45.0
35.0
Untreated
25.0
30.0155
105
105 + Agrotain
105 + G77
15.0
20.0 105 + DMPP
D45 105
D45 155 SD
D45 155
5.0
10.0
N‐Sure
0.0July 17 July 31 August 7 August 22
Nitrate‐N at 2 – 3 Feet in Soil A t 15August 15
Average at start of trial (July 2) = 1.6 ppm20.0
b
14 0
16.0
18.0
b
b
b
10.0
12.0
14.0
aab
b
6.0
8.0
a
a
a
2.0
4.0
aaa
0.0Untreated Standard Moderate Agrotain
PlusG77 DMPP D45 105 D45 SD D45 155 Nsure
Irrigation Events in Relation to Crop ET from Thinning to Harvest
Nitrate‐N at 2 ‐ 3 Feet in Soil A st 31August 31
8.0
b
6.0
7.0b
b
4.0
5.0 b
3.0
4.0
aa a
1.0
2.0
a a a aa
0.0Untreated Standard Moderate Agrotain
PlusG77 DMPP D45 105 D45 SD D45 155 Nsure
SummarySummary
• All nitrogen technologies showed great promise for improving nitrogen use efficiency
• Moderate level of N fertilization had improved yield with Agrotian Plus, DMPP, D45 and N-Sure under the conditions in this trial
SummarySummary
• Given the great NUE of the CRF, the rates should be examined to see if we can reduce the loss of nitrate beyond the rootzonenitrate beyond the rootzone observed in this trial
SummarySummary
• The use of these technologies does not preclude the need for pgood irrigation management