Crop residue removal and cover crops impact soil hydrological properties and soybean yield. Key findings: 1. Low residue removal increased soil organic carbon by 22% in topsoil compared to high removal. Cover crops also increased topsoil carbon. 2. Low removal decreased bulk density by 7-9% in topsoil and subsoil compared to high removal. Cover crops decreased bulk density by 5% in subsoil. 3. Low removal and cover crops increased water infiltration rates by 66% and 82% respectively compared to alternatives. 4. Low removal and cover crops increased soil water retention and storage, particularly in topsoil and subsoil. 5. Treatments did not significantly impact soybean

1. Kopila Subedi-Chalisea, Ekrem Ozlua,b*,
Sandeep Kumara, and Jose Guzmana
aDepartment of Agronomy, Horticulture and Plant Science,
and Department of Soil Science, University of Wisconsin,
Madison
SWC Conference 2017, Madison, WI
Crop Residue Removal and Cover Crop Impact on
Soil Hydrological Properties, Water Storage, and
Soybean Yield

2. • Introduction
• Materials and Methods
• Results and Discussion
• Conclusions
• Acknowledgments
Outline
2

3. Crop residue is removed from soil for:
 Biofuel production
 Animal feed
 Industrial raw materials
3
Crop Residue Removal

4. • Corn biomass as biofuel production will reach up to
112 million of dry ton by 2020 and 256 million dry
tons by 2030 (DOE, 2011).
• Excessive uses of crop residue may impact in long
term productivity of soil (Blanco-Canqui & Lal, 2009,
Wegner et al., 2015).
• Sustainable residue removal rate varies from 25% to
50% (Graham et al., 2007; Johnson et al.,
2016;Wilhelm et al., 2004).
4
Concerns of Crop Residue Removal

5. • No-till system
• Cover crops
• Nutrient management
• Crop rotation
Source: UMN
5
Conservation Practices

6. 6
• Restore soil carbon
• Improve soil hydrological properties
• Conserve moisture
Crop Residue and Cover Crops

7. • Cover crops used after removing corn residue can help in
improving the soil organic carbon and hence the soil
hydrological properties, water storage and water use
efficiency.
7
Study Hypothesis

8. 1. Assess the impacts of crop residue removal and cover
crops on soil organic carbon and soil hydrological
properties under soybean phase of Corn (Zea mays
L.)- Soybean (Glycine max L.) rotation.
2. Assess the impacts of crop residue removal and cover
crops on soil water storage, soybean yield and water
use efficiency.
8
Study Objectives

9. • Location: USDA-ARS North Central Agricultural
Research Laboratory (NCARL), Brookings, SD.
• Crop rotation: Corn (Zea mays L.) – Soybean (Glycine
max L.) rotation (2000)
• Plot design: Randomized complete block design
12
Experimental Site

10. Low residue removal (LRR) High residue removal (HRR)
10
Residue Removal Treatments

11. • Winter rye (Secale cereale) after corn
• Winter rye (Secale cereale) + Hairy Vetch (Vicia villosa)
after soybeans
Cover crops (CC) No cover crops (NCC)
11
Cover Crops Treatments

12. • Core samples and auger samples were collected in spring
2014 and 2015.
• Sampling depths 0-5 cm and 5-15 cm
12
Soil Sampling and Analysis

13. • Soil organic carbon (SOC) and total nitrogen (TN)
• Bulk density (BD)
• Soil penetration resistance (SPR)
• Water infiltration rate (IR)
• Soil water retention (SWR)
13
Soil Parameters

14. Total carbon and total nitrogen (TruSpec CHN analyzer )
• Air dried at ambient temperature
• Grounded to pass 2 mm screen and further grounded
for TC and TN analysis
14
SOC and TN Analysis

15. 15
Bulk Density
Bulk density was calculated using
• Core method (Grossman and Reinsch, 2002)

16. • Soil penetration resistance (Eijkelkamp-type hand
penetrometer)
16
Soil Penetration Resistance

17. • Soil water infiltration (Reynolds et al., 2002)
• Double ring method
17
Water Infiltration

18. Soil water retention (Klute and Dirksen, 1986)
• Tension table (0, -0.4, -1, -2.5,-5 kPa)
• Ceramic pressure plate (-10, -30 kPa)
18
Soil Water Retention Analysis

19. 19
Soil Water Storage and Crop Yield
Analysis
• Soil moisture (2016) – May through October (2016)
• Sampling depth: 0 -5 cm, 5-15 cm, 15-30 cm, 30-45 cm
• Weather data was collected from National Climate Data
Center (NCDC)
• Soybean yield was calculated by harvesting 15 m of
middle two rows from each plots.

20. • ANOVA and mixed models used for comparing the soil
properties under different residue rates and cover crops
using PROC Mixed in SAS (9.4).
• Statistical differences were declared significant at α < 0.05.
20
Statistical Analysis

21. Depths
0-5 cm 5-15 cm 0-5 cm 5-15 cm
SOC TN
Treatments --------------------g kg-1--------------
Residue Removal
LRR 26.23a 21.00a 2.14a 1.75a
HRR 21.52b 19.80a 1.83b 1.68a
Cover Crop
CC 24.00a 20.57a 2.00a 1.73a
NCC 23.80a 20.22a 1.97a 1.71a
Analysis of Variance (P>F)
Residue (R) <0.01 0.184 <0.01 0.18
Cover crop (C) 0.84 0.689 0.81 0.68
R × C 0.06 0.326 0.049 0.32
21
SOC and TN
 LRR : SOC- 22% and TN - 17% (0 – 5 cm)

22. 22
2014 2015 2016
Depths (cm)
Treatments 0-5 5-15 0-5 5-15 0-5 5-15
------------Mg m-3------------
Residue Removal
LRR 1.41a 1.42a 1.30b 1.37a 1.29b 1.34b
HRR 1.42a 1.44a 1.40a 1.37a 1.38a 1.39a
Cover Crop
CC 1.40a 1.43a 1.30b 1.36a 1.32a 1.33b
NCC 1.43a 1.43a 1.39a 1.38a 1.35a 1.40a
Analysis of Variance (P>F)
Residue (R) 0.68 0.62 0.001 0.83 0.001 0.006
Crop (C) 0.30 0.92 0.005 0.13 0.11 0.002
R × C 0.04 0.40 0.08 0.25 0.08 0.23
Bulk Density (BD)
• LRR: 2015 – 7 % , 2016 – 9% (0 - 5) , 4% (5-15) CC : 2015 - 7% (0 – 5 cm) , 2016 - 5% (5- 15 cm)

23. 23
Soil Penetration Resistance (MPa)
Treatments 0-5 cm 5-15 cm
Residue Removal
LRR 2.23b 2.37b
HRR 2.77a 3.01a
Cover Crop
CC 2.24b 2.46b
NCC 2.76a 2.92a
Analysis of Variance (P<F)
Residue (R) 0.009 0.001
Crop (C) 0.01 0.01
R x C 0.07 0.03
Soil Penetration Resistance (SPR)
 LRR: 25% (0-5 cm) and 27 % (5-15 cm) CC : 23% (0-5 cm) and 19% (5 – 15 cm)

24. 24
Treatments
Infiltration Rate
2014 2015
----------------mm h-1-----------
Residue
Removal
LRR 108.2a
87.1a
HRR 64.8b 71.1b
Cover Crop
CC 111.3a 88.5a
NCC 61.7b 69.6b
Analysis of Variance (P>F)
Residue (R) 0.03 0.02
Crop (C) 0.03 0.01
R × C 0.11 0.89
Soil Water Infiltration
 LRR: 66 % (2014) and 22 % (2015) CC : 82% (2014) and 27% (2015)

25. 25
Soil Water Retention (2014)
 LRR increased water
retention for depth
0 -5 cm at all
pressures and for
depth 5 -15 cm
depth higher SWR
was observed for 0
and -0.4 kPa.
 CC significantly
increased water
retention at depth 0
– 5 cm for 0 kPa.
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100(m3m-3)
0-5 cm LRR
HRR
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
5-15 cm LRR
HRR
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
(m3m-3)
Pressure (-kPa)
0-5 cm CC
NC
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
Pressure (-kPa)
5-15 cm
CC
NC

26. 26
Soil Water Retention (2015)
 LRR significantly
increase water
retention for surface
depth in - 2.5, -5, -10
and -30 kPa .
 LRR treatment has
significantly higher
water retention for 0
and -0.4 kPa in depth
5 -15 cm.
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
(m3m-3)
0-5 cm LRR
HRR
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
5-15 cm
LRR
HRR
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
(m3m-3)
Pressure (-kPa)
0-5 cm CC
NC
0.30
0.40
0.50
0.60
0.01 0.1 1 10 100
Pressure (-kPa)
5-15 cm CC
NC

27. 0
0.1
0.2
0.3
0.4
15-May 15-Jun 15-Jul 15-Aug 15-Sep 15-Oct
θm3m-3
Day of sample collection
Soil Volumetric moisture- Depth 5-15 cm
LRR HRR
27
Soil Volumetric Moisture Content
 For 0 - 5 cm (16 and 22% on May and October)
 For 5 - 15 cm (23% during August sampling)
 For 15 - 30 cm (18% during August sampling)
 For 30 - 45 cm ( 25, 16% during June and August sampling)
0
0.1
0.2
0.3
0.4
θm3m-3
Soil volumetric moisture - Depth 15 - 30 cm
LRR HRR
0
0.1
0.2
0.3
0.4
15-May 15-Jun 15-Jul 15-Aug 15-Sep 15-Oct
θm3m-3
Day of sample collection
Soil volumetric moisture - Depth 30 – 45 cm
LRR HRR
0
0.1
0.2
0.3
0.4
0.5
θm3m-3 Soil volumetric moisture-Depth 0 - 5 cm
LRR HRR

28. 28
Soil Volumetric Moisture Content
0
0.1
0.2
0.3
0.4
15-May 15-Jun 15-Jul 15-Aug 15-Sep 15-Octθm3m-3
Soil volumetric moisture - Depth 30 - 45 cm
CC NCC
0
0.1
0.2
0.3
0.4
θm3m-3
Soil volumetric moisture - Depth 0 - 5 cm
CC NCC
0
0.1
0.2
0.3
0.4
15-May 15-Jun 15-Jul 15-Aug 15-Sep 15-Oct
θm3m-3
Soil volumetric moisture - Depth 5 - 15 cm
CC NCC
0
0.1
0.2
0.3
0.4
θm3m-3
Soil volumetric moisture - Depth 15 - 30 cm
CC NCC
 For 0 - 5 cm (23 and 16% during May and June sampling)
 For 5 - 15 cm (28% during August sampling)
 For 30 - 45 cm (16% during June sampling)

29. 0
20
40
60
80
15-May26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Day of sample collection
Water storage - Depth 30 - 45 cm
LRR HRR aa a a
b a
b
b a a a
b
29
0
10
20
30
15-May26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Water storage - Depth 0 - 5 cm
LRR HRR
0
20
40
60
15-May26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Day of sample collection
Water storage - Depth 5 - 15 cm
LRR HRR
0
20
40
60
80
15-May26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Water storage - Depth 15 - 30 cm
LRR HRR
Soil Water Storage
ba
aa
aa
a a
a
b aa aa
aa aa b
a b
a
aa
a
a aa
a a
a
b
aa a a
 For 0 - 5 cm (7 and 14.5% on May and October)
 For 5 - 15 cm (21% during August sampling)
 For 15 - 30 cm (19% during August sampling)
 For 30 - 45 cm ( 21, 21,15% during May June and August sampling)

30. 30
Soil Water Storage
aa
a a a a
a a
a
a a a
0
20
40
60
80
15-May 26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm Day of sample collection
Soil water storage - Depth 30 - 45 cm
CC NCC
0
10
20
30
15-May26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Soil water storage - Depth 0 - 5 cm
CC NCCa
b aa a
a
a
a a a a a
0
50
100
15-May26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Soil water storage - Depth 15 - 30 cm
CC NCC
a a
a a a a a a a a
a b
0
20
40
60
15-May 26-May 27-Jun 20-Aug 20-Sep 21-Oct
mm
Day of sample collection
Soil water storage - Depth 5 - 15 cm
CC NCC
a
a
a
a a
a
b
a a
b
a
a
 For 0 - 5 cm (7 % during May Sampling)
 For 5 - 15 cm (21% during August sampling)
 For 15 - 30 cm (19% during August sampling)

31. 31
Treatments ET Soybean Yield
WUE
--mm-- ---kg ha-1-- kg ha-1 mm-1
Residue Removal
LRR 2279a 2708a 1.19a
HRR 2268a 2738a 1.21a
Cover Crop
CC 2281a 2906a 1.27a
NCC 2267a 2540b 1.12b
Analysis of Variance (P<F)
Residue (R) 0.13 0.71 0.59
Crop (C) 0.05 0.003 0.003
R × C 0.22 0.38 0.32
Evapotranspiration(ET), Soybean Yield and Water
Use Efficiency (WUE)
 Cover crop treatment significantly increased soybean yield by 14% and
WUE by 13%

32. 33
Conclusions
• Low residue removal (LRR) had a positive effect on
bulk density, SOC, soil penetration resistance, water
infiltration, water retention and pore size distribution.
• Cover crop reduced bulk density, increased water
infiltration, water retention and pore size distribution.
• Volumetric moisture content was higher under LRR and
cover crop treatments.
• Significant impact of cover crop on soybean yield and
Water Use Efficiency (WUE) was observed, wheras,
LRR did not significantly impact on WUE.

33. • Volumetric moisture content was higher under Low
Residue Removal (LRR) and cover crop treatments.
• Significant impact of cover crop on soybean yield and
Water Use Efficiency (WUE) was observed.
• LRR did not significantly impact on WUE.
34
Conclusions

34. • Funding for the project is provided by SD AES and
USDA-NIFA
• Lab Team
Acknowledgements

35. • DOE, U. S. (2011). US billion-ton update: biomass supply for a bioenergy and bioproducts
industry. ORNL/TM-2011/224.
• Blanco-Canqui, H., & Lal, R. (2007). Soil and crop response to harvesting corn residues for
biofuel production. Geoderma, 141(3), 355-362.
• Graham, R. L., Nelson, R., Sheehan, J., Perlack, R., & Wright, L. L. (2007). Current and
potential US corn stover supplies. Agronomy journal, 99(1), 1-11.
• Grossman, R., and Reinsch, T. (2002). 2.1 Bulk density and linear extensibility. Methods of
Soil Analysis: Part 4 Physical Methods, 201-228.
• Johnson, J. M., Strock, J. S., Tallaksen, J. E., & Reese, M. (2016). Corn stover harvest
changes soil hydrology and soil aggregation. Soil and Tillage Research, 161, 106-115.
• Klute, A., and Dirksen, C. (1986). Hydraulic conductivity and diffusivity: Laboratory
methods. Methods of Soil Analysis: Part 1—Physical and Mineralogical Methods, 687-734.
• Reynolds, W., Elrick, D., and Youngs, E. (2002). Single-ring and double-or concentric-ring
infiltrometers. Methods of soil analysis. Part 4, 821-826.
References

36. Thank you !!!