Transcript Biodegradable Mulches After Six Months Field Incubation

Soils Working Group
2012 Update
Jennifer Moore-Kucera, Ph.D.
Texas Tech University
13 March 2012
Team Members
Jennifer Moore Kucera
(Grad student: Chenhui Li)
Jaehoon Lee
(Grad student: Rob Raley)
Marion Brodhagen
Debbie Inglis - Mount Vernon NWREC
Carol Miles - Mount Vernon NWREC
Drew Corbin -Snohomish Co. Extension
2010-2012 SWG Objectives
Chem
Bio
 Bury weathered BDMs and extract at
6, 12, 18, 24 (?) mo.
 Measure % area loss of each BDM
 Evaluate changes in soil quality
properties
Inherent
SQI
Starch-based
Certified compostable
Products
Tested
Control
Cellulosic
paper-like
OMRI Certified
Experimental
Spunbond
Polylactic Acid
Material
Cutting BDM pieces
• AFTER final harvest(~Oct ‘10):
• BDM pieces (~103 cm2) are cut,
inserted in nylon mesh bags
(161cm2; 250 μm openings)
with soil and
• Multiple sets are buried
(10-15 cm) for up to 2 yrs
• A set is extracted ~ every 6 mo.
RIP
Nylon mesh bags
Burial
Anemometer
Light sensor
Air Temp
RH %
Soil Temp
% Area Reduction
 Extract bags
 Remove BDM pieces
 Wash and mat on transparency
 Measure area (cm2)
 Photograph (‘ground truth’)
Spunbond and WeedGuard
6 Months
12 Months
Spunbond 0% (24)
WeedGuard
TX, WA > 99% (16)
TN 0% (3); 14 (1OF);
83-95% (2HT,2OF)
Spunbond 0% (24)
WeedGuard
TX, WA 100% (16)
TN 100%, 83% (7,1HT)
0 
6 mo  12 mo
BDM % reduction (# of reps)
0 
6 mo  12 mo
BioBag and BioTelo
6 Months
BioBag
TX 0% (1HT); 5-18% (7)
TN & WA 0% (16)
BioTelo
TX 5-29% (8)
TN & WA 0% (16)
12 Months
BioBag
TX 100% (2HT); 74-94% (6)
TNHT 0% (4**); TNOF 5-32% (4)
WA 0% (16)
BioTelo
TXHT 100% (1HT,1OF), 52-81% (6)
TNHT 6, 0% (1,3); TNOF 32-81% (4)
WA 88, 0% (1OF,7)
BDM average reduction (# of reps)
Questions for team
Why does TX have the most degradation of BioBag and
BioTelo products?
Does it depend on pre-burial status of mulch?
 Need data from 2010 visual field assessments (CWG)
 Need data from 2010 materials testing (MWG)
Does it depend on soil temp and moisture?
 Which data set to use (avg, max, min, daily, monthly, 3-weeks
prior to extraction?)
?? Relationship b/w % elongation at
breaking and % area loss
Tensile strength data from Karen Leonas
Soil Quality Index Flow Chart
• Web Soil Survey (GPS coordinates)  soil suborder
Inherent • Texture, climate, slope, weathering/mineral class
• Biological (Biomass C, Nmin, β-glucosidase)
Dynamic • Chemical (Total organic C, pH, EC)
SMAF
• Adjust for inherent soil properties
• Adjust for crop, season, EC method, region, etc.
Stats
• Run in SAS to determine effects of site (Tunnel), Treatment
(BDMs), and Tunnel * Trt interaction
Soil Quality Index Flow Chart
• Web Soil Survey (GPS coordinates)  soil suborder
Inherent • Texture, climate, slope, weathering/mineral class
• Biological (Biomass C, Nmin, β-glucosidase)
Dynamic • Chemical (Total organic C, pH, EC)
SMAF
• Adjust for inherent soil properties
• Adjust for crop, season, EC method, region, etc.
Stats
• Run in SAS to determine effects of site (Tunnel), Treatment
(BDMs), and Tunnel * Trt interaction
Soil Quality Index Flow Chart
• Web Soil Survey (GPS coordinates)  soil suborder
Inherent • Texture, climate, slope, weathering/mineral class
• Biological (Biomass C, Nmin, β-glucosidase)
Dynamic • Chemical (Total organic C, pH, EC)
SMAF
• Adjust for inherent soil properties
• Adjust for crop, season, EC method, region, etc.
Stats
• Run in SAS to determine effects of site (Tunnel), Treatment
(BDMs), and Tunnel * Trt interaction
Soil Quality Index Flow Chart
• Web Soil Survey (GPS coordinates)  soil suborder
Inherent • Texture, climate, slope, weathering/mineral class
• Biological (Biomass C, Nmin, β-glucosidase)
Dynamic • Chemical (Total organic C, pH, EC)
SMAF
• Adjust for inherent soil properties
• Adjust for crop, season, EC method, region, etc.
Stats
• Run in SAS to determine effects of site (Tunnel), Treatment
(BDMs), and Tunnel * Trt interaction
Tennessee SQI Post 6 Months Incubation
100
*
SQI (5 variables)
80
 No significant effect of BDM
60
40
20
0
NM
SB
BB
BT
WG
Avg
BDM treatment
HT
OF
Texas SQI Post 6 Months Incubation
60
50
SQI (5 variables)
SQI 6-months extraction
*
40
30
20
10
0
NM
SB
BB
BT
BDM treatment
WG
Avg
treatment in TN or TX
 Significant effect of tunnel
treatment with higher SQI
for inside tunnels vs. open
field
WA SQI after 6 months
Washington SQIextraction
Post 6 Months Incubation
60
 Tunnel*TRT
BDM trts within
each tunnel site
 SQI in WG and BB
higher in open
field vs. hightunnel
SQI (5 variables)
 WG > all other
50
40
HT
OF
B
C
*
B
*
C
A
B
B
A
B
BC
30
20
10
0
NM
SB
BB
BT
WG
BDM treatment
Significant tunnel x trt interaction (p=0.004)
Within each tunnel treatment, dIfferent capital letters indicate
significant differences between BDM treatments.
An asterix indicates significant difference between tunnel treatments
within each BDM treatment.
SMAF variables
TN
TX
WA
Soil series
Dewey
Acuff/Olton
Skagit
Suborder
Udult
Ustoll
Aquept
Texture
Silt loam
Loam/clay loam
Silt loam
% clay
22
21.5/28.5
20.5
Slope
0-3%
0-1
0-1
Weathering
Hi (Ultisols)
1 (calc)
3 (slightly)
Mineral class
Non smectititic/ nonglassy
Non smectititic/ nonglassy
Non smectititic/nonglassy
Climate
> 170 degree days/
> 550 ppt
> 170 degree days/
< 550 ppt
< 170 degree days/
> 550 ppt
Humid
Arid
Humid
1:1
1:1
1:1
Region
EC method
**TN and WA please confirm these values!
Other Biological Measurements
Soil microbial community composition
PLFA profiling (broad taxonomic level info; no
phylogenetic info)
N-acetyl-β-glucosaminidase
Chitin (fungal cell walls)  amino sugars (org N)
DNA sequencing (Marion Brodhagen)
Brodhagen lab: ID of microbial BDM degraders
Findings so far:
Most are Ascomycetes
Most of these bacteria and fungi are oligotrophs
 live on trace nutrients, like volatiles in air
 difficult to prove that they degrade BDMs
rather than simply colonizing
 still working on this; ideas??
 keystone species in BDM degradation?
 extreme efforts to remove all C sources
other than BDMs:
-- only brand new glassware
-- separate, new reagents
-- airtight, activated charcoal-filtered box to
remove volatiles
Method for demonstrating growth on BDMs as sole C source:
under optimization for publication
1
2
1
2
3
1 3: Exclusion of C sources other than
BDMs: cut to uniform weights, UVsterilized, and then placed in liquid or atop
solid (agar) medium and inoculated. Agar
can be a C source but it’s difficult to grow
these in broth aerobically.
4
4: Box for culturing fungi under activatedcharcoal filtered air
Conclusions so far
 BDM colonizers are mostly Ascomycetes and a few Basidiomycetes
(yeasts).
 Need longer sequence reads and possibly other genes in addition to 18S
rRNA genes for species-level identification.
 Do we need species-level identification at this point?
 These fungi are metabolically diverse:
-- degrade many (unusual) substrates
-- make lots of secondary metabolites… including some toxins.
 Eladia is known to degrade L-sugars. Conventional wisdom is that at
least for PLA, the L-sugars that remain are likely recalcitrant. Hopefully
more to come on this?
SWG Summary
All 6 month assessments are complete
WG: 20/24 samples degraded > 84%
12 month assessments still in progress are
PLFA profiling and some chemical analyses
WG consistently degraded across all 3
ecoregions within 12 months
BioBag & BioTelo: TX > TN > WA (0%)
SWG Summary
 Minimal changes in SQI due to BDM treatment
 SQI higher in HT compared to OF in TX and TN
 In WA SQI was higher under WG compared to
all other treatments
 Potential fungal degraders may pose pathogenic
properties…details still coming
Future SWG Goals
 Complete 18 mo. analyses (samples arrive next wk!)
(?Need for 24 mo assessments?)
 Present oral and poster presentations at 2012 ASHS
(FL) & SSSA (OH) meetings
 Publish 4 papers?
1. SMAF
2. % area reduction (with Carol and Karen?)
3. Marion’s DNA work
4. Jaehoon and Rob’s Environmental Data Analyses
5. Others?
Questions/Comments?
Thank you!
Soil/Environmental Properties
TN
TX
WA
Soil pH
6.7
8.1
6.6
Texture
Silt loam
Loam/clay loam
Silt loam
1.26%
0.734%
1.4%
?
12.6°C
?
TOC
Soil temp Oct
2010 – Apr 2011
Soil moisture
SAS Programs
TX and TN program
Proc Sort Data=TX;
By Trt Tunnel;
title ‘SQI TX 1.1';
Proc Mixed Data=TX;
Class Blk Trt Tunnel;
Model SQI = Trt Tunnel
TRT*Tunnel/ddfm=satterth;
RANDOM BLK BLK*TRT;
lsmeans TRT Tunnel
TRT*Tunnel / PDIFF; run;
quit;
WA program
Proc sort data = WA;
By Tunnel Blk Trt;
title ‘SQI WA 1.1';
Proc mixed data = WA;
Class Blk Tunnel Trt;
Model SQI =Tunnel|TRT/
ddfm=satterth;
Random Blk Blk*Tunnel
Blk*TRT(Tunnel);
lsmeansTunnel|TRT/pdiff;
run;quit;
Burial & Extraction Times
TN
HT
2010 Burial Sep 16-21
TX
WA
OF
HT
OF
HT
OF
Oct 21-22
Oct 11
Oct 12
Oct 20
Oct 11
2011 T1
extraction
Feb 28
Apr 11
Mar 24
Apr 25
May 3
May 23
T1
months
buried
5.4
5.7
5.5
6.5
6.5
7.5
2011 T2
extraction
Oct 3
Oct 3
Nov 8
Nov 8
Oct 24
Oct 24
T2
months
buried
12.7
11.6
13.1
13.1
12.6
12.3
Ranking Tensile Strength at Burial With
% Area Loss at 6 and 12 months
Tensile strength
Location TRT
TN-OF
BB
TN-HT
BB
TX-OF
BB
TX-HT
BB
WA-OF
BB
WA-HT
BB
Machine
BF
5.2
6.1
5.7
5.1
5.8
6.9
PEB
9.7
14.5
16.2
14.5
23.4
61.6
Transverse
BF
3.4
4.8
5.1
4.1
5.3
5.3
PEB
7.5
11.7
13.7
9.0
14.7
32.3
6 months 12 months
0.0
15.0
0.0
0.0
9.0
84.0
7.0
91.0
0.0
0.0
0.0
0.0
TN-OF
TN-HT
TX-OF
TX-HT
WA-OF
WA-HT
BT
BT
BT
BT
BT
BT
5.7
5.7
5.3
3.7
5.8
6.0
11.5
9.6
16.7
10.0
16.4
37.0
3.4
4.5
4.2
4.0
5.1
5.3
6.1
6.1
8.7
7.1
10.5
11.4
0.0
0.0
17.0
14.0
0.0
0.0
57.0
1.5
78.0
71.0
22.0
0.0
TN-OF
TN-HT
TX-OF
TX-HT
WA-OF
WA-HT
WG
WG
WG
WG
WG
WG
22.0
55.4
2.0
38.8
2.1
33.0
2.8
2.8
0.7
1.8
0.5
2.2
26.0
24.1
2.0
23.7
2.2
11.3
3.2
3.0
1.2
2.8
1.3
2.3
45.0
64.0
100.0
100.0
100.0
100.0
100.0
96.0
100.0
100.0
100.0
100.0
Tensile strength data from Karen Leonas
SWG Accomplishments

Lee, J., Inglis, D., Miles, C., Moore-Kucera, J., Wszelaki, A. May 19–21, 2010. Soil quality and thermal properties under biodegradable mulches. Annual
Southeastern Regional Soil Physics Meeting. Nashville, Tennessee.

Moore-Kucera. September 27, 2011. ‘Biodegradable mulches:Short-term degradability and impacts on soil health.’ HortScience 46(8).

Moore-Kucera, J. Spring, 2010. Three lectures, one field tour, and one lab class on high tunnel and BDM research delivered to undergraduate soil science
students at TTU, Lubbock, TX.

2011 Fall Issue. Pulling plastic: Texas Tech researchers dig into biodegradable mulch. Kucera-Moore, J. and Wallace, R.W. (TTU/TAMU). Texas Tech
Discoveries Magazine. Lubbock, TX.

June 6, 2011. Researchers Dig into Biodegradable Mulch. Kucera Moore, J. and Wallace, R.W. (TTU/TAMU). Texas Tech Today Web Magazine. TTU,
Lubbock, TX.

Cowan, J., Miles, C., Inglis, D., Leonas, K., Moore-Kucera, J., Wszelaki, A., Wallace, R., Hayes, D., and Wadsworth, L. 2010. Proceedings paper:
Evaluating potential biodegradable mulches for high tunnel and field vegetable production. Agricultural Plastics Congress, July 31–August 1, Palm Desert,
California. Slide presentation.

Inglis, D., Miles, C., Belasco, E., Brodhagen, M., Corbin, A., Espinola-Arredondo, A., Hayes, D., Jones, R., Lee, J., Leonas, K., Liu, H., Marsh, T., MooreKucera, J., Wadsworth, L., Wallace, R., Walters T., and Wszelaki. A. 2010. Biodegradable Mulches for Specialty Crops Produced Under Protective Covers.

Miles, C., Hayes, D., Moore-Kucera, J., Brodhagen, M., Marsh, T., Corbin, A., Wallace, R., Wszelaki, A., Walters, T. Lee, J., and Inglis, D. 2011.
Biodegradable alternatives to plastic mulch. In: Transforming Lives Transforming Landscapes. The Business of Sustainable Water Buffer Management.
Steenbergen, F. van, A. Tuinhof and L. Knoop (Eds). Wageningen, The Netherlands: 3R Water Secretariat (book chapter; 1200 books printed).

Chenhui Li*, Marko Davinic, Lisa M. Fultz, Jaehoon Lee, Russel W. Wallace, Jeff Martin, Robert Raley Jr., Carol Miles, Debbie A. Inglis and Jennifer
Moore-Kucera. 2011. Biodegradable Mulches: Short-Term Degradability and Impacts On Soil Health. Abstracts, Annual Meeting of the
American Society of Agronomy, 16-19 October 2011, San Antonio, TX.

Moore-Kucera, J. , M. Davinic, L. Fultz, J. Lee, C.A. Miles, M. Brodhagen, J. Cowan, R.W. Wallace, A. Wszelaki, J. Martin, J. Roozen, B.
Gundersen and D.A. Inglis. 2011. Biodegradable Mulches: Short-term degradability and impacts on soil health. HortScience 46(10):S68.
American Society for Horticultural Science, September 2011,Waikoloa, HI.
