1. Physiological response of switch grass
for bioenergy alley cropping in soils of
varying depths in Central Missouri
Sougata Bardhan &
Shibu Jose

2. Why Switch Grass?
I. Corn, Soybean, Sugarcane = Food crisis/cost
II. 2nd generation biofuels are more ecologically
sustainable
III. Switch Grass is a native plant
a) Perennial
b) Adaptive
c) Deep rooted
d) High genetic diversity
Source: Ceres Inc.
Marginal lands – not prime lands!!

3. Flood Laboratory

4. Drought Simulator

5. Erosion

6. Degraded Lands!!

7. Soil Productivity for Assessment of
Renewable Energy Crops (SPARC)
Established by
N. E. Kitchen in
2009
32 plots
Soil Depth
Species
Switchgrass
Corn
Soybean

8. Claims Galore!!

9. Nitrogen Utilization Efficiency
We used isotope labeled N fertilizer in micro plots
with same rates as the trial
Jose 2009

10. Long-term Storage of C

11. Light Response Curves
We selected 3 plots each for Corn and Switch Grass
Adjacent Corn-Switch Grass plots
3 top soil depths
2 cm,
22 cm,
42 cm
Measured in end-August to early-September, 2013
Licor 6400 with a leaf chamber
Jose 2009

12. Temperature and Precipitation

13. Photosynthesis Rate
2 cm top soil
Corn
Decline in Photosynthesis rate %
120
SwG
100
80
60
40
20
0
1500
1000
500
250
100
50
Irradiance Photon (umol quanta m-2 s-1)
0

14. Photosynthesis Rate
22 cm top soil
Corn
Decline in Photosynthesis rate%
120
SwG
100
80
60
40
20
0
1500
1000
500
250
100
50
Irradiance Photon (umol quanta m-2 s-1)
0

15. Photosynthesis Rate
42 cm top soil
Corn
Decline in Photosynthesis rate%
120
SwG
100
80
60
40
20
0
1500
1000
500
250
100
50
Irradiance Photon (umol quanta m-2 s-1)
0

16. Corn and Switch Grass Yield
(2009 – 2011)
Kitchen, N.E., (personal communication)

17. Drought 2012

18. Corn and Switch Grass Yield
(2012)
140
120
Yield/ha
100
80
60
40
Corn
20
SwG
0
0
20
40
60
80
Soil Depth (cm)
Kitchen, N.E., (personal communication)
100

19. In Conclusion……..
Switch grass can be a very good alley crop for
deployment in feedstock production system.
Switch grass is adaptable to poor and degraded
soils.
Results from 15N study will provide information
about nutrient dynamics
Much work still remains……..
Regional screening to identify best cultivars and
other management practices.

20. Thank You for your time
For Questions:
bardhans@missouri.edu