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

1. No‐till pumpkin production using
cover crops in the Great Plains:
soil health and fruit yield
Cathryn J. Davis, DeAnn Presley, Peter
Tomlinson, Cary Rivard, Jason Griffin,
Kim Oxley

2. Introduction
• Demonstrate effectiveness of using cover
crops in pumpkin production
• Assess the impact of different cover crop
species on soil health measured by:
– Soil aggregation (water stable aggregates)
– Microbial biomass carbon

3. Pumpkins and Soil Health
• U.S. per capita consumption of pumpkins is
2.4 kg (USDA‐ERS, 2014)
• 400 ha of pumpkins grown per year in Kansas,
important in agri‐tourism
• Challenge: Are there practices that can benefit
soil health while maximizing horticultural crop
yields?
(Pieper et al., 2015, HortScience)

4. Locations & Treatments
1. Conventional Tillage
2. Rye
3. Rye / Pea
4. Rye / Hairy Vetch
5. Rye / Canola
6. Rye / Hairy Vetch / Canola
7. Oats
8. Oats / Pea
• Plot size 9.1 x 18.3 m2
• RCBD 3 replications
• 2 locations, 3 years
– K‐State Horticulture Research &
Extension Center, Olathe KS
– J.C. Pair Horticulture Center,
Haysville KS (south of Wichita)

5. Field operations and methods
• Fall 2012 study established in conventionally
tilled fields
• Study area rototilled
• Fall covers were planted, spring covers were
planted
• Cover crops roller crimped
• Pumpkins transplanted into residue
– Thus, the pumpkins were no‐tilled

6. John C. Pair Center
Early Spring Cover Crop Growth

7. Late Spring Cover Crop
(Prior to termination)

8. Pumpkin no‐till planted
into cover crop residue

10. Harvest
(prior to fall tillage)

11. Methods, continued
• After the pumpkins are picked, we collect soil
samples
• Then the entire field is thoroughly tilled up
• Then the fall covers are planted in certain plots
• In spring, the covers are planted
• Late spring: all covers are rolled, and the
conventional treatment is rototilled again
• Then pumpkins are planted no‐till

12. Methods
• Sampled twice per year
• Spring: after pumpkins are transplanted
• Fall: immediately after pumpkin harvest
• Infiltration, bulk density (0‐5 and 5‐10 cm)
• Wet aggregate stability (Kemper and Rosenau)
• Microbial biomass C* and dissolved OC
*Chloroform fumigation extraction

13. 0
1
2
3
4
5
6
Olathe Fall 13
0
1
2
3
4
5
6
Wichita Fall 13
Soil Physical Properties
Mean Weight Diameter (mm)
p = 0.72 p = 0.88
One‐way analysis of variance with
treatment as the variable

14. 0
1
2
3
4
5
6
Wichita Spring 14
0
1
2
3
4
5
6
Olathe Spring 14
Soil Physical Properties
Mean Weight Diameter (mm)
p = 0.67 p < 0.05
B B
AB A
A
AAA

15. 0
1
2
3
4
5
6
Olathe Fall 14
0
1
2
3
4
5
6
Wichita Fall 14
Soil Physical Properties
Mean Weight Diameter (mm)
p = 0.29 p = 0.12

16. 0
1
2
3
4
5
6
Wichita Spring 15
0
1
2
3
4
5
6
Olathe Spring 15
Soil Physical Properties
Mean Weight Diameter (mm)
p < 0.03 p < .0001
A AA
AA
A
A
B
A
CD
ABCD
ABCAB
BCD
D
AB

17. 0
1
2
3
4
5
6
Olathe Fall 15
0
1
2
3
4
5
6
Wichita Fall 15
Soil Physical Properties
Mean Weight Diameter (mm)
p = 0.11 p < 0.01
A AAA
A AA
B
Olathe 1/5 and Wichita 3/5 samplings:
Cover crops better structure
Spring: More differences than Fall
Structure improving over time?

18. b
a
a a a
b
b
a
b
b b b
a
a
0
10
20
30
40
50
60
70
80
90
100
>4.75 2.00 to
4.75
1.00 to
2.00
0.50 to
1.00
0.25 to
0.50
<0.25 Total
Ag (%)
MWD
Water Stable Aggregates
(%)
Size Fraction (mm)
Olathe Fall 2015
No cover Cover

19. Microbial Biomass Carbon (μg C g‐1soil)
0
50
100
150
200
250
300
350
400
Olathe Fall 2013
p = 0.42

20. 0
50
100
150
200
250
300
350
400
Wichita Spring 2014
0
50
100
150
200
250
300
350
400
Olathe Spring 2014
Microbial Biomass Carbon (μg C g‐1soil)
p = 0.48 p = 0.19
Both sites: Cover vs. no cover was significant

21. 0
50
100
150
200
250
300
350
400
Wichita Fall 2014
0
50
100
150
200
250
300
350
400
Olathe Fall 2014
Microbial Biomass Carbon (μg C g‐1soil)
p = 0.51 p = 0.93
Olathe: Cover vs. no cover was significant

22. 0
50
100
150
200
250
300
350
400
Olathe Spring 2015
Microbial Biomass Carbon (μg C g‐1soil)
p = 0.40 p = 0.52
0
50
100
150
200
250
300
350
400
Wichita Spring 2015
Neither site: no significant difference for cover or no cover

23. 0
50
100
150
200
250
300
350
400
Wichita Fall 2015
0
50
100
150
200
250
300
350
400
Olathe Fall 2015
Microbial Biomass Carbon (μg C g‐1soil)
p = 0.99 p = 0.53
Neither site: no significant difference for cover or no cover

24. Olathe Fruit Yield (Mg ha‐1) 2013
0
10
20
30
40
50
60
P < 0.03
A AB
BC
C
BCBC BC BC

25. Olathe Fruit Yield (Mg ha‐1) 2013 – 2014
0
10
20
30
40
50
60
2013 2014
P<0.22P < 0.03
A AB
BC
C
BCBC BC BC

26. Olathe Fruit Yield (Mg ha‐1) 2013 – 2015
0
10
20
30
40
50
60
2013 2014 2015
p = 0.34P = 0.22P < 0.03
A AB
BC
C
BCBC BC BC

27. Wichita Fruit Yield (Mg ha‐1) 2013
0
10
20
30
40
50
60
2013
p < 0.001
AB A
ABC ABC
ABCBC
D
C

28. Wichita Fruit Yield (Mg ha‐1) 2013 ‐2014
0
10
20
30
40
50
60
2013 2014
p = 0.20p < 0.001
AB A
ABC ABC
ABCBC
D
C

29. Results and Conclusions
• Relative to the control, cover crops improved
soil aggregation, 2‐3 years into the study
– And all plots are rototilled after harvest
• 4 out of 5 site years, no fruit yield penalty for
no‐tilling pumpkins into rolled cover crops
• Lessons learned: Pumpkins needed to be
fertigated, cover crops need timely termination,
pumpkins should be rotated with other crops to
break weed and disease cycles

36. Acknowledgements
• Brett Lynn, Sarah Tatarko, Taylor Fischer, Peter
Tomlinson, Cary Rivard, Kimberly Oxley, Jason Griffin,
DeAnn Presley
• Development and Adoption of No‐Till and Minimum
Tillage Vegetable Production Systems in the Great
Plains. National Conservation Innovation Grant,
September 1, 2012 – September 1, 2015. $221,282.

37. Olathe Fruit Yield (Mg/ha‐1) 2013 – 2015
p < 0.34P<0.22
P < 0.03
0
5
10
15
20
25
30
35
40
2013
0
5
10
15
20
25
30
35
40
2014
0
5
10
15
20
25
30
35
40
Tillage
Rye
Rye / Pea
Rye / Vetch
Rye / Canola
Rye/Vetch/Can…
Oats
Oats / Winter…
2015

38. 2013‐2014 Wichita Fruit Yield (Mg/ha‐1)
0
10
20
30
40
50
60
2013
0
10
20
30
40
50
60
2014
p < 0.001 p < 0.20

39. Soil Biological Properties
Microbial Biomass Carbon
p < 0.48 p < 0.19
0
50
100
150
200
250
Microbial Biomass Carbon
(μg C g‐1soil)
Spring 2014 Wichita Olathe

40. Soil Biological Properties
Microbial Biomass Carbon
0
50
100
150
200
250
Microbial Biomass Carbon
(μg C g‐1soil)
Fall 2014
Wichita Olathe
p < 0.51 p < 0.93