THE EFFECT OF UREASE INHIBITOR NBPT ON AMMONIA ...
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ACKNOWLEDGMENTS ORGANIZATION GRAND CHALLENGES GREAT SOLUTIONS ASA, CSSSA, & SSSA International Annual Meeting Nov. 2-5, 2014 | Long Beach CA, USA Studies: 34 laboratory and field Survey of Literature: Cab Abstract, Science Direct, Scopus, Web of Science and Google Scholar Observations: 112 published 1990-2013 Climate Zones: Temperate, Cold, Tropical and Arid Treatments: Urea and Urea + NBPT Soil and Managment Factors Soil pH (<5.5; 5.5-6.5; >6.5-7.5 and >7,5) Soil Textures (Coarse: <18; Medium: 18-35 and Fine: >35 % clay) Soil Carbon (>1; 1-2 and >2 %) NBPT Rates (< 530; 530-1060 and >1060 mg kg -1 urea) N Fertilizer Rates (<80; 80-160 and >160 kg ha -1 N) Data Analysis Cumulative NH 3 losses (Sigmoid function using SigmaPlot ) Y = Y max /(1 + exp (-(t - t 1/2 )/b)) , Y: cumulative NH 3 loss as a percentage of applied N; Y max : maximum NH 3 loss; t: days after fertilizer application, t 1/2 : time at which 50 % of the losses occur; b: parameter of the equation. % Decrease in NH 3 volatilization (R-Project) MATERIALS AND METHODS I n all studies analyzed, urea+NBPT reduced losses compared to urea. The results indicated that, when conditions favor losses, treating urea with NBPT is effective in reducing ammonia volatilization loss. CONCLUSIONS The urease inhibitor AGROTAIN® nitrogen stabilizer (market by Koch Agronomic Services, Wichita, KS, USA) slows urea hydrolysis and reduces loss potential of ammonia (NH 3 ) volatilization. AGROTAIN has N-(n-butyl) thiophosphoric triamide (NBPT) as active ingredient that needs to be converted to its analog N-(n-butyl) phosphoric triamide (BNPO) to inhibit the urease enzyme. Loss potential depends on soil and environmental conditions such as soil pH, soil moisture, temperature, and amount and time of rainfall after fertilizer application. Thus, the inhibitor effect on ammonia volatilization loss is variable. Urea hydrolysis reaction: This study integrated available results of 34 laboratory and field studies to compare ammonia volatilization loss from urea and urea treated with NBPT. INTRODUCTION AND OBJECTIVE THE EFFECT OF UREASE INHIBITOR NBPT ON AMMONIA VOLATILIZATION LOSS FROM UREA FERTILIZER: A META-ANALYSIS Aijânio Gomes de Brito Silva 1 ; Rafael Otto 1 ; Cleiton Sequeira 2 1 Department of Soil Science, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil, [email protected] ; [email protected] ; 2 Koch Agronomic Services, LLC, Wichita, KS, USA, [email protected] . RESULTS 9.0d 5.4d 2.8d 4.3d 3.3d 2.2d Fig 1 - Cumulative losses of NH 3 for 42 days after aplication of urea (UREA) and urea treated with urease inhibitor NBPT (UREA+NBPT). The points of the curves adjustment correspond to the arithmetic average of daily cumulative volatilization compiled from 34 scientific papers. The dashed red lines (UREA) and blue lines (UREA+NBPT) represent the days for losses of 25, 50 and 75% of applied N. 30/17 32/10 14/15 33/5 109/29 0 15 30 45 60 75 90 105 Soil pH % decrease in NH 3 volatilization losses (42 days) > 7,5 >6-5 -7.5 5.5-6.5 <5.5 Mean 28/8 9/5 49/12 86/20 0 15 30 45 60 75 90 105 Soil Textures % decrease in NH 3 volatilization losses (42 days) Coarse Medium Fine Mean 38/9 28/14 34/8 100/28 0 15 30 45 60 75 90 105 Soil Carbon (%) % decrease in NH 3 volatilization losses (42 days) > 2.0 1.0-2.0 < 1.0 Mean 4/3 24/8 80/23 108/32 0 15 30 45 60 75 90 105 N Fertilizer Rates (kg ha -1 ) % decrease in NH 3 volatilization losses (42 days) > 160 80-160 < 80 Mean 29/8 29/13 38/13 96/26 0 15 30 45 60 75 90 105 NBPT Rates (mg kg -1 ) % decrease in NH 3 volatilization losses (42 days) > 1060 530-1060 < 530 Mean Fig 2 – Groups of soil pH effect (A), soil textures (B), soil carbon (C), N fertilizer rates (D) and NBPT rates (E) on reduction of NH 3 losses using urease inhibitor NBPT 42 days after fertilizaer application. The sample size (number of pairs urea and urea+NBPT) is shown on the left of the confidence intervals (95%) followed by the number of studies reviewed. A B C D E urease CO (NH 2 ) 2 + 2 H 2 O (NH 4 ) 2 CO 3 (NH 4 ) 2 CO 3 + H 2 O 2 NH 4 + + OH - + HCO 3 - NH 4 + + OH - NH 3 + H 3 O
Transcript of THE EFFECT OF UREASE INHIBITOR NBPT ON AMMONIA ...
ACKNOWLEDGMENTS ORGANIZATION GRAND CHALLENGES GREAT SOLUTIONS
ASA, CSSSA, & SSSA International Annual Meeting Nov. 2-5, 2014 | Long Beach CA, USA
Studies: 34 laboratory and field
Survey of Literature: Cab Abstract, Science Direct, Scopus, Web of Science and
Google Scholar
Observations: 112 published 1990-2013
Climate Zones: Temperate, Cold, Tropical and Arid
Treatments: Urea and Urea + NBPT
Soil and Managment Factors
Soil pH (<5.5; 5.5-6.5; >6.5-7.5 and >7,5)
Soil Textures (Coarse: <18; Medium: 18-35 and Fine: >35 % clay)
Soil Carbon (>1; 1-2 and >2 %)
NBPT Rates (< 530; 530-1060 and >1060 mg kg-1 urea)
N Fertilizer Rates (<80; 80-160 and >160 kg ha-1 N)
Data Analysis
Cumulative NH3 losses (Sigmoid function using SigmaPlot )
Y = Ymax /(1 + exp (-(t - t1/2)/b)),
Y: cumulative NH3 loss as a percentage of applied N; Ymax: maximum NH3 loss;
t: days after fertilizer application, t1/2: time at which 50 % of the losses occur;
b: parameter of the equation.
% Decrease in NH3 volatilization (R-Project)
MATERIALS AND METHODS
In all studies analyzed, urea+NBPT reduced losses compared to urea.
The results indicated that, when conditions favor losses, treating urea with
NBPT is effective in reducing ammonia volatilization loss.
CONCLUSIONS
The urease inhibitor AGROTAIN® nitrogen stabilizer (market by Koch Agronomic
Services, Wichita, KS, USA) slows urea hydrolysis and reduces loss potential of ammonia (NH3) volatilization. AGROTAIN has N-(n-butyl) thiophosphoric triamide (NBPT) as active ingredient that needs to be converted to its analog N-(n-butyl) phosphoric triamide (BNPO) to inhibit the urease enzyme. Loss potential depends on soil and environmental conditions such as soil pH, soil moisture, temperature, and amount and time of rainfall after fertilizer application. Thus, the inhibitor effect on ammonia volatilization loss is variable.
Urea hydrolysis reaction:
This study integrated available results of 34 laboratory and field studies to
compare ammonia volatilization loss from urea and urea treated with NBPT.
INTRODUCTION AND OBJECTIVE
THE EFFECT OF UREASE INHIBITOR NBPT ON AMMONIA VOLATILIZATION LOSS FROM UREA FERTILIZER: A META-ANALYSIS
Aijânio Gomes de Brito Silva 1; Rafael Otto 1; Cleiton Sequeira 2 1 Department of Soil Science, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil, [email protected]; [email protected];
2 Koch Agronomic Services, LLC, Wichita, KS, USA, [email protected].
RESULTS
9.0d 5.4d
2.8d
4.3d 3.3d
2.2d
Fig 1 - Cumulative losses of NH3 for 42 days after aplication of urea (UREA) and urea treated with urease inhibitor NBPT (UREA+NBPT). The points of the curves adjustment correspond to the arithmetic average of daily cumulative volatilization compiled from 34 scientific papers. The dashed red lines (UREA) and blue lines (UREA+NBPT) represent the days for losses of 25, 50 and 75% of applied N.
30/17
32/10
14/15
33/5
109/29
0 15 30 45 60 75 90 105
Soil
pH
% decrease in NH3 volatilization losses (42 days)
> 7,5
>6-5 -7.5
5.5-6.5
<5.5
Mean
28/8
9/5
49/12
86/20
0 15 30 45 60 75 90 105
Soil
Text
ure
s
% decrease in NH3 volatilization losses (42 days)
Coarse
Medium
Fine
Mean
38/9
28/14
34/8
100/28
0 15 30 45 60 75 90 105
Soil
Ca
rbo
n (
%)
% decrease in NH3 volatilization losses (42 days)
> 2.0
1.0-2.0
< 1.0
Mean
4/3
24/8
80/23
108/32
0 15 30 45 60 75 90 105 N
Fer
tiliz
er R
ates
(kg
ha
-1)
% decrease in NH3 volatilization losses (42 days)
> 160
80-160
< 80
Mean
29/8
29/13
38/13
96/26
0 15 30 45 60 75 90 105
NB
PT
Rat
es (
mg
kg-1
)
% decrease in NH3 volatilization losses (42 days)
> 1060
530-1060
< 530
Mean
Fig 2 – Groups of soil pH effect (A), soil textures (B), soil carbon (C), N fertilizer rates (D) and NBPT rates (E) on reduction of NH3 losses using urease inhibitor NBPT 42 days after fertilizaer application. The sample size (number of pairs urea and urea+NBPT) is shown on the left of the confidence intervals (95%) followed by the number of studies reviewed.
A B
C D
E
urease CO (NH2) 2 + 2 H2O (NH4) 2 CO3 (NH4 ) 2 CO 3 + H 2O 2 NH4
+ + OH - + HCO 3 -
NH4
+ + OH - NH3 + H 3 O
