effects of various soil amendments on soil test p values david brauer, glen aiken, dan pote...
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Effects of various soil amendments on soil test P values
David Brauer, Glen Aiken, Dan PoteARS/USDA, Booneville AR
S.J. Livingston, L.D. NortonARS/USDA, W. Lafayette IN
T.R. Way and J.H. EdwardsARS/USDA, Auburn, AL
Acknowledgements
• Additional funds were provided by:
– Southern Plains Area Office/ARS
– U.S. Poultry and Egg Association
Rationale and Objectives
• Rationale– Manure applications from concentrated animal
feeding operations have increased soil P levels
– P transport from agricultural land to surface water is undesirable
• Objectives– Evaluate various amendments to decrease
soil test values for P
First Experiment-Kurten TX
Farm History- Kurten Site
• Farm occupies 200-300 acres
• Dairy operation- Post WWII era (30 years)
• Hen laying operation since early 1980’s
– 500,000 birds
– 30-35 Mg of wet manure produced daily (70% moisture)
Aerial view of Kurten Site
Kurten TX site: Climate
• Rainfall– About 900 mm of annual rainfall– About 100 mm occurs in July and August,
thus leading to low soil moisture
• Annual Average temperature– About 20 C
Kurten Site- Soil Characteristics
• Zulch fine sandy loam (thermic udertic Paleustalfs)
• Chemical characteristics Ap horizon– Mehlich III P ~1,500 mg/ kg– Bray-1 P ~3,000 mg/ kg– DRP (25:1) 50 mg/ kg– Soil Ca ~5,500 mg/ kg– Soil pH 7.8
Soil amendments at Kurten Site
• Gypsum (2 rates, 1.5 and 5 Mg/ ha)
• Alum (1.4 Mg/ ha)
• Waste paper (24.4 Mg/ ha)
• Waste paper plus Gypsum
• Waste paper plus Alum
• Waste paper plus Alum and Gypsum
Experimental Protocol
• Amendments applied annually 1999 to 2001 in March.
• Soil samples (0-7.5 cm and 7.5-15 cm) collected in July/August from 1999 to 2004.
• Bray-1 P and DRP (25 ml water per 1 g soil).
• DRP solutions analyzed for Ca-readily reactive Ca.
Ca and Al additions (kg/ha)
Annual Amt Total Amt
Ca Al Ca Al
1.5 Mg Gypsum/ha 350 1,050
5 Mg Gypsum/ha 1,160 3,580
1.4 Mg Alum/ ha 130 390
22.4 Mg Paper/ha 100 300
Bray-1 P (Means for 1999-2001)
0 1000 2000 3000 4000 5000
unamended control
Low Gypsum
High Gypsum
Alum
Waste Paper
Bray-1 P (mg P/kg soil)
Soil DRP (Means for 1999-2001)
0.0 10.0 20.0 30.0 40.0 50.0 60.0
unamended control
Low Gypsum
High Gypsum
Alum
Waste Paper
DRP (mg P/kg soil)
Changes in Soil DRP with time
20
30
40
50
60
70
1998 1999 2000 2001 2002 2003 2004 2005
Year
So
il D
RP
(m
g P
/kg
so
il) Unamended
high Ca sulfate
Changes in “reactive”soil Ca with Gypsum from 1999 to 2001
0.0
50.0
100.0
150.0
200.0
250.0
Control 1.5 Mg/ha 5.0 Mg/ha
mg
Ca/
kg
so
il (
dry
wt)
Rainfall Simulation Data (Livingston et al. 1999)
0 0.5 1 1.5 2 2.5 3 3.5
unamendedcontrol
Gypsum (5Mg/ha)
Gypsum plusWaste Paper
Runoff P (kg P/ ha/hr)
DRP
Sediment
Booneville Experiment
• Ability to change soil P levels with waste paper
• Leadvale silt loam
• Low P soil (<60 mg P/kg Bray-1 P values)
• 3 rates of waste paper (22, 44 or 88 Mg/ha to supply 90, 170 or 350 kg Al/ha)
Booneville Experimental Area
Waste Paper Addition on Soil P
0 20 40 60 80
0
22
44
88
Was
te p
aper
(M
g/h
a)
Soil P test value (mg P/kg soil)
DRP
Bray-1 P
Waste paper and Soil Bulk Density
1.0
1.1
1.2
1.3
1.4
0 20 40 60 80 100
Waste paper product added (Mg ha-1)
So
il b
ulk
den
sity
(g
cm
-3) Year 1
Year 2
Conclusions
• Gypsum can reduce runoff and DRP when soil P values are very high– Low soluble, reactive Ca– Ca added in amounts equal to Mehlich P
• Decreases in runoff P with amendments– Maybe associated with changes in soil
structure