Materials and Methods
1
Ammonia Volatilization Following Banding of Urea to Seven Agricultural Soils P. Rochette, M. Chantigny, D.A. Angers, J.D. MacDonald, L. Lamontagne, N. Bertrand and F. Boiffard. Soils and Crops Research Center, Québec City, QC, Canada. Materials and Methods Materials and Methods Introduction Introduction Conclusions Conclusions Introduction Introduction Air intake 100 m L 0.05 M H3PO4 100 m L W ater G as counter Vacuum pum p Enclosure 100 m L 0.05 M H3PO4 20 cm Soilcore Air intake 100 m L 0.05 M H3PO4 100 m L W ater G as counter Vacuum pum p Silicasand Enclosure 100 m L 0.05 M H3PO4 20 cm 10 cm 15 cm 12 cm 30 cm • Significant losses of NH 3 can occur when urea is incorporated in bands. • Magnitude of losses differs among soils. • The impact of incorporating urea on NH 3 volatilization in bands is strongly influenced by soil properties, and decreases with increasing clay content , CEC and buffer capacity . • Volatilization is more closely related to soluble than with total soil NH 4 -N. We conclude that : 1) volatilization is lower in soils with a greater NH 4 adsorption, 2) the increased volatilization observed under field conditions on the S4 soil by Rochette et al. (2009a) cannot be generalized. • Total NH 4 -N in the urea band increased similarly in all soils. • Soil solution NH 4 -N in the urea band increased more in soils with lower clay content. References References • Urea accounts for 40% of global nitrogen fertilizers sales. • Surface application of urea to agricultural soils can result in high NH 3 volatilization losses (Sommer et al., 2004). • Soil incorporation of broadcasted urea reduces volatilization. • Incorporation in bands is not as efficient because of a large localized pH increase in the urea band (Rochette et al., 2009a). • NH 3 volatilization from urea incorporated in bands may be influenced by soil properties. Assess the propensity of soils with contrasting characteristics to emit NH 3 from urea incorporated in bands. Objective Objective • Strongly to moderately acid agricultural soils (7) with contrasting clay content were selected in the Quebec City region (Table 1). • Surface 10 cm of each soil was sampled in October 2008. • Soils were sieved to ≤ 2 mm and moistened to -200 kPa. • Soils were packed to 1.00 g cm -3 in stainless steel cylinders (I.D.: 20 cm; H : 12 cm) (Fig. 1) and incubated for 28 d using a dynamic chamber at 20°C (Rochette et al., 2009b). • Soil pH, NH 4 + -N and NO 3 - - N content were monitored in the urea band in containers (0.8 m x 0.4 m x 0.1 m) (Fig. 2). Sommer, S.G., J.K. Schjørring, and O.T. Denmead. 2004. Ammonia emission from mineral fertilizers and fertilized crops. Adv. Agron. 82: 557-622. Rochette, P., D.A. Angers, M.H. Chantigny, N. Bertrand, M.-O. Gasser and J.D. MacDonald. 2009a. Banding of urea increased ammonia volatilization in a dry acidic soil. J. Environ. Qual., 38:1383-1390. Rochette, P., D.A. Angers, M.H. Chantigny, J.D. MacDonald, N. Bissonnette, and N. Bertrand, N. 2009b. Ammonia volatilization following surface application of urea to no-till and conventionally tilled soils: a laboratory comparison. Soil Till. Res. 103:310-315. Soil pH increased by 1.9 to 3.2 units in response to hydrolysis of urea. Relationships between cumulative NH 3 -N losses and selected soil properties. Table 2. Cumulative volatilization Soil Cumulative NH 3 losses (% of N applied) S1 17.3 S2 11.6 S3 10.5 S4 1.4 S5 0.3 S6 0.2 S7 0.0 Fig. 1. Soil incubation dynamic systems. Fig. 2. Soil containers used for soil sampling and analysis. Table 1. Selected properties of the seven soils at initiation of experiment. Cumulative NH 3 losses (mg N m -2 ) Total NH 3 volatilization: • varied between 1 and 18% of applied urea- N, • were greatest on S1 followed by S2 and S3, • were ≈ 0 for S5, S6 and S7 and very small on S4. -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 m g N H 4 -N kg so il -1 0 100 200 300 400 500 600 700 S1 S2 S3 S4 S5 S6 S7 Tim e afterurea application (d) -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 m g N H 4 -N kg so il -1 0 200 400 600 800 1000 1200 S1 S2 S3 S4 S5 S6 S7 Results and Discussion Results and Discussion “Soil solution” NH 4 -N (CaCl 2 0.005M) “Total” NH 4 -N (KCl 2M) Tim e afterurea application (d) -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 V olatilization m g N H 3 -N m -2 h -1 0 5 10 15 20 S1 S2 S3 S4 S5 S6 S7 Volatilization Volatilization: • was very low in 4 out of 7 soils, • began 3 to 4 days after urea application, • increased rapidly followed by a gradual decline, • was greater in soils with lower clay Tim e afterurea application (d) -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 S oilpH 5 6 7 8 9 S1 S2 S3 S4 S5 S6 S7 Soil pH Cumulative volatilization losses: • were highly correlated with soil clay content, CEC and buffer capacity, • NH 3 volatilization losses were negligible for soils with: Clay content above 20%, CEC above 20 meq/100 g, Buffer capacity above 1.8. B ase U rease activity SoilI.D . Clay Sand pH (H 2O ) O rg.C arbon Ca CEC Saturation m g NH4-N % % % m eq/100g m eq/100g % kg -1 dry soilh -1 S1 4.2 87.4 5.27 1.02 1.8 12.1 19.2 216 S2 7.0 55.9 5.85 2.24 6.0 15.7 44.9 873 S3 7.6 56.9 5.28 1.90 4.5 14.8 34.2 327 S4 16.5 28.7 5.15 2.10 4.3 17.2 27.3 906 S5 28.3 23.8 6.02 1.62 11.5 23.7 63.7 263 S6 32.3 31.9 5.67 2.57 12.9 28.0 55.3 793 S7 62.1 6.8 5.57 3.08 15.2 36.9 60.4 957 CEC 10 15 20 25 30 35 40 0 500 1000 1500 2000 2500 3000 % Clay 0 20 40 60 0 500 1000 1500 2000 2500 3000 Buffercapacity (pH units) 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 0 500 1000 1500 2000 2500 3000 M ax.rise in pH 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 0 500 1000 1500 2000 2500 3000 Soluble N H 4 -N 400 500 600 700 0 500 1000 1500 2000 2500 3000 Total N H 4 -N 800 900 1000 1100 1200 0 500 1000 1500 2000 2500 3000 y = 4960 e -0.17x ; r 2 = 0.99 y = 44421 e -0.24x ; r 2 = 0.87 y = e 0.01x ; r 2 = 0.28 y = -1801x + 4041; r 2 = 0.81y = 1285 - 2444 ; r 2 = 0.99
description
Ammonia Volatilization Following Banding of Urea to Seven Agricultural Soils P. Rochette, M. Chantigny, D.A. Angers, J.D. MacDonald, L. Lamontagne, N. Bertrand and F. Boiffard. Soils and Crops Research Center, Québec City, QC, Canada. Results and Discussion. Table 2. Cumulative volatilization - PowerPoint PPT Presentation
Transcript of Materials and Methods
Ammonia Volatilization Following Banding of Urea to Seven Agricultural Soils P. Rochette, M. Chantigny, D.A. Angers, J.D. MacDonald, L. Lamontagne, N. Bertrand and F. Boiffard.
Soils and Crops Research Center, Québec City, QC, Canada.
Materials and MethodsMaterials and Methods
IntroductionIntroduction
ConclusionsConclusions
IntroductionIntroduction
Soil core
Airintake
100 mL0.05 M H3PO4
100 mLWater
Gascounter
Vacuumpump
Silica sand
Enclosure 100 mL0.05 M H3PO4
20 cm
10 cm
15 cm 12 cm30 cmSoil core
Airintake
100 mL0.05 M H3PO4
100 mLWater
Gascounter
Vacuumpump
Silica sand
Enclosure 100 mL0.05 M H3PO4
20 cm
10 cm10 cm
15 cm15 cm 12 cm12 cm30 cm30 cm
• Significant losses of NH3 can occur when urea is incorporated in bands.• Magnitude of losses differs among soils.• The impact of incorporating urea on NH3 volatilization in bands is strongly influenced by
soil properties, and decreases with increasing clay content, CEC and buffer capacity.• Volatilization is more closely related to soluble than with total soil NH 4-N.
We conclude that : 1) volatilization is lower in soils with a greater NH4 adsorption,2) the increased volatilization observed under field conditions on the
S4 soil by Rochette et al. (2009a) cannot be generalized.
• Total NH4-N in the urea band increased similarly in all soils.• Soil solution NH4-N in the urea band increased more in soils with
lower clay content.
ReferencesReferences
• Urea accounts for 40% of global nitrogen fertilizers sales.
• Surface application of urea to agricultural soils can result in high NH3 volatilization losses (Sommer et al., 2004).
• Soil incorporation of broadcasted urea reduces volatilization.
• Incorporation in bands is not as efficient because of a large localized pH increase in the urea band (Rochette et al., 2009a).
• NH3 volatilization from urea incorporated in bands may be influenced by soil properties.
Assess the propensity of soils with contrasting characteristics to emit NH3 from urea incorporated in bands.
ObjectiveObjective
• Strongly to moderately acid agricultural soils (7) with contrasting clay content were selected in the Quebec City region (Table 1).
• Surface 10 cm of each soil was sampled in October 2008.• Soils were sieved to ≤ 2 mm and moistened to -200 kPa.• Soils were packed to 1.00 g cm-3 in stainless steel cylinders (I.D.:
20 cm; H : 12 cm) (Fig. 1) and incubated for 28 d using a dynamic chamber at 20°C (Rochette et al., 2009b).
• Soil pH, NH4+-N and NO3--N content
were monitored in the urea band in containers (0.8 m x 0.4 m x 0.1 m) (Fig. 2).
Sommer, S.G., J.K. Schjørring, and O.T. Denmead. 2004. Ammonia emission from mineral fertilizers and fertilized crops. Adv. Agron. 82: 557-622.
Rochette, P., D.A. Angers, M.H. Chantigny, N. Bertrand, M.-O. Gasser and J.D. MacDonald. 2009a. Banding of urea increased ammonia volatilization in a dry acidic soil. J. Environ. Qual., 38:1383-1390.
Rochette, P., D.A. Angers, M.H. Chantigny, J.D. MacDonald, N. Bissonnette, and N. Bertrand, N. 2009b. Ammonia volatilization following surface application of urea to no-till and conventionally tilled soils: a laboratory comparison. Soil Till. Res. 103:310-315.
Soil pH increased by 1.9 to 3.2 units in response to hydrolysis of urea.
Relationships between cumulative NH3-N losses and selected soil properties.
Table 2. Cumulative volatilization
Soil Cumulative NH3 losses (% of N applied)
S1 17.3S2 11.6S3 10.5S4 1.4S5 0.3S6 0.2S7 0.0
Fig. 1. Soil incubation dynamic systems.
Fig. 2. Soil containers used for soil sampling and analysis.
Table 1. Selected properties of the seven soils at initiation of experiment.
Cum
ulat
ive
NH
3 lo
sses
(m
g N
m -2
)
Total NH3 volatilization:
• varied between 1 and 18% of applied urea-N,• were greatest on S1 followed by S2 and S3,• were ≈ 0 for S5, S6 and S7 and very small on S4.
-4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
mg
NH 4-N
kg
so
il-1
0
100
200
300
400
500
600
700S1S2S3S4S5S6S7
Time after urea application (d)
-4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
mg N
H 4-N
kg
so
il-1
0
200
400
600
800
1000
1200 S1S2S3S4S5S6S7
Results and DiscussionResults and Discussion
“Soil solution” NH4-N (CaCl2 0.005M)
“Total” NH4-N (KCl 2M)
Time after urea application (d)
-4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Vola
tiliz
atio
n m
g N
H3-N
m-2 h
-1
0
5
10
15
20S1S2S3S4S5S6S7
Volatilization
Volatilization: • was very low in 4 out of 7 soils,• began 3 to 4 days after urea application,• increased rapidly followed by a gradual decline,• was greater in soils with lower clay content.
Time after urea application (d)
-4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Soil
pH
5
6
7
8
9S1S2S3S4S5S6S7
Soil pH
Cumulative volatilization losses:• were highly correlated with soil clay content, CEC and buffer capacity,
• NH3 volatilization losses were negligible for soils with:
Clay content above 20%, CEC above 20 meq/100 g, Buffer capacity above 1.8.
Base Urease activity
Soil I.D. Clay Sand pH (H2O) Org. Carbon Ca CEC Saturation mg NH4-N
% % % meq/100g meq/100g % kg-1dry soil h-1
S1 4.2 87.4 5.27 1.02 1.8 12.1 19.2 216S2 7.0 55.9 5.85 2.24 6.0 15.7 44.9 873S3 7.6 56.9 5.28 1.90 4.5 14.8 34.2 327S4 16.5 28.7 5.15 2.10 4.3 17.2 27.3 906S5 28.3 23.8 6.02 1.62 11.5 23.7 63.7 263S6 32.3 31.9 5.67 2.57 12.9 28.0 55.3 793S7 62.1 6.8 5.57 3.08 15.2 36.9 60.4 957
CEC
10 15 20 25 30 35 40
0
500
1000
1500
2000
2500
3000
% Clay
0 20 40 60
0
500
1000
1500
2000
2500
3000
Buffer capacity (pH units)
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
0
500
1000
1500
2000
2500
3000
Max. rise in pH
1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
0
500
1000
1500
2000
2500
3000
Soluble NH4-N
400 500 600 700
0
500
1000
1500
2000
2500
3000
Total NH4-N
800 900 1000 1100 1200
0
500
1000
1500
2000
2500
3000
y = 4960 e-0.17x ; r2 = 0.99 y = 44421 e-0.24x ; r2 = 0.87 y = e0.01x ; r2 = 0.28
y = -1801x + 4041; r2 = 0.81 y = 1285 - 2444 ; r2 = 0.99
