influence of aeration implements, amendment and soil taxa on phosphorus losses in grasslands
DESCRIPTION
Influence of Aeration Implements, Amendment and Soil Taxa on Phosphorus losses in Grasslands. D.H. Franklin, D.M. Butler and M.L. Cabrera . Introduction. Attenuation of rainfall within the solum may help: Extend forage productivity during droughty periods - PowerPoint PPT PresentationTRANSCRIPT
INFLUENCE OF AERATION IMPLEMENTS, AMENDMENT AND SOIL TAXA ON PHOSPHORUS LOSSES IN GRASSLANDS
D.H. Franklin, D.M. Butler and M.L. Cabrera
Introduction Attenuation of rainfall within the solum may
help: Extend forage productivity during droughty periods Retard flooding during periods of heavy rainfall Move nutrients and contaminants into soil to be
better utilized, transformed or sequestered
Animal manures can be An environmental hazard An economic resource for added N, P, K, Ca and C
Introduction Following surface application of broiler litter
mechanical aeration may be able to increase infiltration and improve soil/nutrient contact time and thereby retain more resources in the soil
Objectives Review three studies, 2 small plot
studies and one field-scale paired watershed study
Determine impact of aeration of runoff volume and P losses in runoff
Mixed fescue-bermudagrass grasslands
Methods – Three studies Mechanical aeration in mixed fescue-
bermudagrass [tall fescue (Festuca arundinacea Schreb.)/bermudagrass (Cynodon dactylon L.)] grasslands
P amendments Broiler litter, dairy slurry, mineral
Soil taxa varied among studies (hydrologic properties)
Hutchins et al. (2007)
Rainfall Simulation – Slit Aeration, 2-m2 Plots Altavista (fine-loamy, mixed, semiactive, thermic Aquic Hapludults)
Spike
TreatmentsNutient - B = Broiler Litter; T Triple Super PhosphateAeration - X = Control (none); S = Spike
Natural Rainfall – Scale 0.8-ha FieldsMultiple Soil taxa, Broiler litter
Treatments Aeration - With &
Without Paired Watersheds
(before and after) Fields 2, 5, 6 were
aeratedCecil (fine,kaolinitic, thermic Typic Kanhapludults), Altavista (fine-loamy, mixed, semiactive, thermic Aquic Hapludults), Helena (fine, mixed, semiactive, thermic Aquic Hapludults), and Sedgefield (fine, mixed, active, thermic, Aquultic Hapludalfs)
Rainfall Simulation - Scale 2 m2 Plots Cecil (fine, kaolinitic, thermic Typic Kanhapludults)
Treatments Nutient O = Control (none); B = Broiler Litter; D =
Dairy Slurry Aeration X = Control; N = No-till (disk); S = Spike;
C = CoreCore
No-till
Results Rainfall Simulation – Slit Aeration, 2 m2 Plots Altavista (fine-loamy, Aquic Hapludults)
Aerated Plots, fertilized with broiler litter attenuated more rainfall
Aeration alone did not affect cumulative mass losses of TKP, DRP, TKN, or NH4-N
Time (min runoff)
Results Rainfall Simulation – Slit Aeration, 2-m2 Plots Altavista (fine-loamy, Aquic Hapludults)
Footslope position attenuated twice as much runoff and Cumulative P
Landscape positionToeslope FootslopeBackslope Shoulder
Cum
ulat
ive
P Lo
ss (k
g P
ha-1
)
0
1
2
3
Cum
ulat
ive
Run
off (
mm
)
0
5
10
15
20
25
a
a
a
a a aa
aa
a a
aa
aa a
a
a
a a
a
b
b
5
30
10
510
30
ShoulderBackslope
FootslopeToeslope
Results Natural Rainfall – Slit Aeration, 0.8-ha Fields
Effect of aeration On Runoff volume varied
Well-drained soil aeration reduced runoff
Poorly-drained soil aeration increased runoff
Results Natural Rainfall – Slit Aeration, 0.8-ha Fields
Effect of aeration On DRP Loss VariedTKP similar to DRP
Well-drained soil aeration reduced P loss
Poorly-drained soil aeration increased P loss
DRP 6 = 0.03* + 1.40 DRP 3r2 = 0.91n = 56
DRP 6 = 0.29* + 1.47 DRP 3r2 = 0.75n = 19
DRP Loss Plot 3 - not aerated (kg P ha-1)
Before AerationAfter Aeration
Runoff 2 = 1.40 + 1.92* Runoff 1r2 = 0.90n = 37
Runoff 2 = 3.00 + 1.14* Runoff 1r2 = 0.75n = 9
DRP Loss Plot 4 - not aerated (kg P ha-1)
DRP Loss Plot 1 - not aerated (kg P ha-1)
0.0 0.5 1.0 1.5 2.0 2.5 3.0DR
P L
oss
Plo
t 5 -
aera
ted
(kg
P h
a-1)
0.0
0.5
1.0
1.5
2.0
DRP 5 = -0.02 + 0.59 DRP 4r2 = 0.92n = 53
DRP 5 = -0.02 + 0.64 DRP 4r2 = 0.94n = 19
b)
c)
Before
After
Before
After
0.0 0.2 0.4 0.6 0.8 1.0DR
P L
oss
Plo
t 2 -
aera
ted
(kg
P h
a-1)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
DRP 2 = 0.06 + 3.13* DRP 1r2 = 0.86n = 38
DRP 2 = 0.13 + 2.02* DRP 1
r2 = 0.79n = 21
0.0 0.5 1.0 1.5 2.0DR
P L
oss
Plo
t 6 -
aera
ted
(kg
P h
a-1)
0
1
2
3
Before AerationAfter Aeration
a)
Before
After
AfterBefore
DRP6 = 0.29** + 1.47 DRP 3r2 = 0.75n = 19
DRP6 = 0.03** + 1.40 DRP 3r2 = 0.91n = 56
Plot 6
Elevation (m)
153.0153.5154.0154.5155.0155.5156.0
Dep
th (c
m)
0
20
40
60
80
100
120
140
Bt StartsRedox Features StartBC Starts
Bt = Redox
Plot 5D
epth
(cm
)
0
20
40
60
80
100
120
140
Plot 2
Elevation (m)
153.0153.5154.0154.5155.0155.5156.0
Dep
th (c
m)
0
20
40
60
80
100
120
140
Results Natural Rainfall – Slit aeration, 0.8-ha Fields
Poorly-drained soils on which aeration exacerbated runoff and P losses had shallower: redoxomorphic features
Bt and Bc horizons
Line colors indicate: Black, depth Bt begins; Red, redox features begin; and green, BC begins
Results Rainfall Simulation – Slit, core and no-till Aeration, 2 m2 Plots, Cecil (fine, kaolinitic Typic Kanhapludults)
Core aeration reduced runoff volume when broiler litter was appliedNone of the mechanical aeration treatments tested reduced runoff when either dairy slurry or no amendments were applied
Time (min runoff)
Runoff volume
Broiler Litter Dairy Slurry No Manure
Run
off V
olum
e (%
of a
pplie
d ra
infa
ll)
0
10
20
30
40
50
60
Core Disk Slit No Aeration
a
bab
b
†
b. PostCmpct
NSNS
Results Rainfall Simulation – Slit, core and no-till Aeration, 2-m2 Plots, Cecil
Core aeration was most effective in reducing P losses in runoff for all P fractions measured
Core No-till Disk Slit None
P e
xpor
t (kg
P h
a-1 )
0
1
2
3
4TKP** TDP** DRP** TBAP** DBAP**
69%
64% 77
%52
%
78%
72% 81
%60
%
91%
82%
84%
63%
90%
82%
79%
63%
Broiler litter, PreCmpct
b† a a ac b ab ac b ab ab a a ab a a a
Results Rainfall Simulation – Slit, core and no-till Aeration, 2-m2 Plots, Cecil
Soils were compacted to simulate cattle grazing
Again core aeration tended to out perform other mechanical aeration treatments on the well-drained Cecil soil
P Export
Core No-till Disk Slit None
P e
xpor
t (kg
P h
a-1 )
0.0
0.5
1.0
1.5
2.0
2.5
3.0Broiler litter, After Compaction
b† a ab aba ab abb
TKP‡ DRP†
SoiL P
Continued P adsorption and relatively low levels of soil P suggest that soil still has further capacity to adsorb P
Broiler Litter Dairy Slurry No Manure
Meh
lich
I Soi
l P (m
g P
kg-1
)
0
10
20
30
40
50
60
70
Baseline PreCmpct PostCmpct
b
b
a
b
c
a
NS
Total suspended sediments
Broiler Litter Dairy Slurry No Manure
Tota
l Sus
pend
ed S
olid
s (k
g ha
-1)
0
50
100
150
200
250
300
Core Disk Slit No Aeration
a
bb
b
†
a. PreCmpctNS
NS
Broiler Litter Dairy Slurry No ManureTo
tal S
uspe
nded
Sol
ids
(kg
ha-1
)
0
50
100
150
200
250
300
Core Disk Slit No Aeration
a bab b
†
b. PostCmpct
NS NS
Conclusions Results varied depending on soils and drainage
class Small Plot Studies
Aerated Plots, fertilized with broiler litter attenuated more rainfall
Footslope position attenuated more rainfall than the shoulder, backslope or toeslope
Core aeration reduced TKP (46%) and DRP ( 62%) from plots fertilized with broiler litter
Core aeration lost significantly less dissolved P fractions (TDP and DRP) than no aeration, slit or no-till aeration
Conclusions Results varied depending on soils
and drainage class
Field Scale Study On fields with well-drained soils, aeration
reduced DRP losses (35%) Aeration exacerbated runoff and P losses in
poorly-drained soils