Effects of various soil amendments on soil test P values

1
Effects of various soil amendments on soil test P
values

• David Brauer, Glen Aiken, Dan Pote
• ARS/USDA, Booneville AR
• S.J. Livingston, L.D. Norton
• ARS/USDA, W. Lafayette IN
• T.R. Way and J.H. Edwards
• ARS/USDA, Auburn, AL

2
Acknowledgements

• Additional funds were provided by
• Southern Plains Area Office/ARS
• U.S. Poultry and Egg Association

3
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

4
First Experiment-Kurten TX
5
Farm History- Kurten Site

• Farm occupies 200-300 acres
• Dairy operation- Post WWII era (30 years)
• Hen laying operation since early 1980s
• 500,000 birds
• 30-35 Mg of wet manure produced daily (70
  moisture)

6
Aerial view of Kurten Site
7
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

8
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 (251) 50 mg/ kg
• Soil Ca 5,500 mg/ kg
• Soil pH 7.8

9
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

10
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.

11
Ca and Al additions (kg/ha)
Annual Amt Annual Amt Total 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
12
Bray-1 P (Means for 1999-2001)
13
Soil DRP (Means for 1999-2001)
14
Changes in Soil DRP with time
15
Changes in reactivesoil Ca with Gypsum from
1999 to 2001
16
Rainfall Simulation Data (Livingston et al. 1999)
17
Booneville Experiment

• Ability to change soil P levels with waste paper
• Leadvale silt loam
• Low P soil (lt60 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)

18
Booneville Experimental Area
19
Waste Paper Addition on Soil P
20
Waste paper and Soil Bulk Density
21
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