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