71st SWCS International Annual Conference July 24-27, 2016 Louisville, KY

1. Effects of FGD Gypsum on Yield
and Soil Properties in Kansas
DeAnn Presley
deann@ksu.edu
@soilsdiva

2. Outline
• Flue Gas Desulfurization gypsum comes from
coal‐burning power plants, marketed under
the name Gypsoil in Kansas
• So now we get less SO4 deposition
– so4_dep_ani.pptx
• Gypsum normally used for sodic soil
reclamation
• Will Gypsoil affect crop yield, grain nutrients,
or soil properties?

3. Soil health*: The ability for a soil to
function as a living system, with
ecosystem and land use boundaries, to
sustain plant and animal productivity,
maintain or enhance water and air
quality, and promote plant and animal
health.
(*Previously referred to as soil quality
and/or soil management)

4. 2013‐2015
• East Central Kansas Experiment Field (Ottawa)
– Corn‐soybean‐corn (strip tilled corn, no‐tilled
soybeans)
– Woodson silt loam <1% slope, 3.6% OM (0‐6”)
– 15 by 30’ plots, hand applied gypsum, 4 reps
• Central Kansas on‐farm w/co‐op
– Alfalfa‐wheat‐sudangrass‐soybeans (no‐till all)
– Ladysmith silty clay loam, 0‐1%, 3.1% SOM (0‐6”)
– ½ mile by 90’ strips, 3 reps
– Commercial spreader applied gypsum
– Farmer did other field operations

5. Treatments
• 0 control
• 0.5 annual (total: 1.5 t)
• 1 t annual (total: 3 t)
• 2 t annual (total: 6 t)
• 2 t in year one, no other applications
• High rates typical for soil improvement,
not plant nutrients
• Some discussion about whether non‐
sodic soils can benefit from FGD gypsum
Buckley and Wolkowski. 2012. Crop Management doi:10.1094/CM‐2012‐0925‐01‐RS.
Norton and Dontsova. 1998. Advances in GeoEcology 31:581‐587.
(1 ton gypsum contains 372 lbs S)

6. Dispersed organic matter, 9/4/2013, Goessel
• Have data, need to extract with GIS

7. Photo by DeAnn Presley, September 2013, field by Goessel, KS

8. VRT Gypsum Map
• Cooperation with Mid Kansas Cooperative
• All GIS analyses done by Ross Benisch,
Precision Ag Specialist

9. Goessel 2014 Wheat (dry year)
No yield differences

10. 2015 Soybeans
Average year, no yield differences

11. Grain properties
• Ottawa: no yield differences
• 2015: slightly more S04‐S and Boron in corn
grain for highest gypsum rates
• Going to go back and analyze soil for
micronutrients (start w/ 2015 soil)
• B is found in FGD wastewater (G.
Hettiarachchi)
• B is found in coal, anywhere from 5 to 200
ppm depending on geologic deposit
Cox et al., 1978. Leaching of boron from coal ash.
Environ. Sci. Technol. 12:722–723.

12. Soil chemical properties
• SO4‐S greatest at highest gypsum
rates
• EC increased at Ottawa site with
increasing gypsum rates, Fall 2015
–0.26 ms/cm for control
–1.11 ms/cm for the 2 ton annual
–p=0.02
–Threshold 4 for saline soil

13. Soil physical properties
• Double ring infiltration
– Inner ring 30 cm (12”), outer ring 75 cm (30”)
– Apply 20 cm (8”) 12 hours before measurement
period
• Ottawa fall 2013 average is 12.3 cm per hr
– The spring 2015 and fall 2015 averaged out to
about 3 cm per hr
• Goessel Spring 2014 and Spring 2015 averaged
0.7 cm per hr
– Fall 2015 averaged 2.7 cm per hr
• Goessel < Ottawa, would have guessed that
• This much variability is often observed

14. Soil physical properties
• Also no differences in oven dry bulk density or
wet aggregate stability
• Within a sampling period, values pretty close,
more variation between sampling times
Ottawa (mm)
F 2013 S 2015 F 2015
2.6 1.6 3.0
2.8 1.8 3.4
2.7 1.5 2.8
2.7 1.6 3.2
2.8 1.9 3.4
0.96 0.85 0.62
Goessel (mm)
F 2013 S 2014 S 2015 F 2015
2.0 3.5 2.0 3.5
1.8 4.4 1.8 4.3
2.1 3.4 1.4 4.9
1.8 5.1 2.2 3.6
2.5 5.2 1.4 4.6
0.19 0.27 0.30 0.26
Rate
t ac-1 yr-1
0
0.5
1
2
2 t once
p-value
Stone, L.R., and A.J. Schlegel. 2009. Tillage and crop rotation phase effects on soil
physical properties in the West-Central Great Plains. Agron. J. 102:483-491.

15. • What is impressive, though…
• Total time consumed
–18 days performing infiltration
measurements
–21* days measuring water stable aggregates
*Estimated

16. Soil health/Biological testing
• At the request of the project’s funding
source, samples were collected for Haney
test and for PLFA testing, both performed
at Ward Laboratories, Kearney, NE
• Both procedures produce a large amount
of data and interpretation of these
results is still in progress.
• Focus on indices.

17. Haney number calculation
• Soil Health Calculation: This number is calculated as 1‐day
CO2‐C divided by the organic C: N ratio plus WEOC/100 plus
WEON/10 to include a weighted contribution of water
extractable organic C and organic N. It represents the overall
health of your soil system. It combines 5 independent
measurements of your soil’s biological properties. The
calculation looks at the balance of soil C and N and their
relationship to microbial activity. This soil health calculation
number can vary from 0 to more than 50. We like to see this
number above 7 and increase over time. This number
indicates your current soil health and what it needs to reach
its highest sustainable state. Keeping track of this Soil Health
number will allow you to gauge the effects of your
management practices over the years.
http://www.wardlab.com/haney/haney_info.aspx

18. Haney Number Ottawa
Rate Fall 2013
t ac-1 yr-1 Haney No.
0 9.9
0.5 7.3
1 9.2
2 9.2
2 t once 7.8
p-value 0.55
Fall 2015
Haney No.
12.2
12.1
11.5
11.4
12.9
0.63
As of 1/26/16 there were no peer-
reviewed articles that define or
explain the relevance of the Haney
number.

19. 8
9
10
11
12
13
14
15
100 110 120 130 140 150
15 Ottawa Corn Yield vs. Haney Soil
Health #
Used plot values

20. 10
12
14
16
18
20
40 45 50 55 60
2015 Goessel Soybean Yield vs.
Haney Soil Health #
Used plot values

21. PLFA Ottawa
Rate Fall 2013
t ac-1 yr-1 PLFA Diversity Index1
0 1.5
0.5 1.4
1 1.2
2 1.3
2 t once 1.5
p-value 0.53
Fall 2015
PLFA Diversity Index
1.5
1.4
1.4
1.5
1.3
0.45
1.6+ excellent
1.5+ to 1.6 very good
1.4+ to 1.5 good
1.3+ to 1.4 slightly above average
1.2+ to 1.3, average
1.1+ to 1.2, slightly below average
Frostegård, Å., A. Tunlid, A., and E. Bath. 2010. Use and misuse of
PLFA measurements in soils. Soil Biol. Biochem. 43:1621-1625.

22. Regarding soil health tests, my clients have…
A. Never asked
me
B. Asked me
what I thought
C. Collected their
own samples
D. Had me collect
samples
Never asked m
e
Asked m
e w
hat I thought
Collected their ow
n sam
ples
Had m
e collect sam
ples
32%
25%
8%
36%
N = 70

23. I have heard of Solvita
A. True
B. False
True
False
79%
21%
N = 70

24. I have heard of Haney
A. True
B. False
True
False
45%
55%
N = 70

25. I have heard of PLFA
A. True
B. False
True
False
77%
23%
N = 70

26. Acknowledgements
• Field work accomplices: Yuxin He and Cathryn
Davis
• Funded by: