Post on 11-Jun-2020
Biodegradation Performance of Cellulosic, Meltblown PLA and Spunbond PLA Mulches in Soil Treatments Used in Crops
Larry C. Wadsworth1 (lwadswor@utk.edu), Douglas G. Hayes2, Annette L. Wszelaki3, Jaehoon Lee2, Karen K. Leonas4 Jeffrey Martin3 Tommy L Washington5 C TylerLeonas4, Jeffrey Martin3,Tommy L. Washington5, C. Tyler Pannell2 and Galina Menlichenko2
1Materials Science & Engineering and Biosystems Engineering & Soil ScienceUniversity of Tennessee, Knoxville (UT)
2UT Biosystems Engineering and Soil Science Department3UT Pl t S i D t t3UT Plant Sciences Department4Washington State Univ. (WSU), Pullman, WA USA991645UT Materials Science & Engineering
“Plastic” Agricultural Mulches: Advantages
Reduced weed problems Enhanced moisture controlReduced evaporationReduced water saturation
Increased soil temperature extension of growing season increased growth rate increased growth rate
Reduced soil compaction Reduced fertilizer leaching Reduced fertilizer leaching Cleaner product Root pruning eliminatedRoot pruning eliminated http://www.ces.ncsu.edu/depts/hort/hil/hil-33.html
“Plastic” Agricultural Mulches: Disadvantages
Costly and laborious to remove
Potential environmental hazard Black plastic (polyethylene) does not biodegrade or
compostable Its persistence in the ecosystem can increase local
pesticide and toxicant concentrations
Greater initial costs Greater initial costs
Increased management of irrigation
Increased soil erosion (between strips of mulch) Increased soil erosion (between strips of mulch)
http://www ces ncsu edu/depts/hort/hil/hil 33 htmlhttp://www.ces.ncsu.edu/depts/hort/hil/hil-33.html
Goals for Biodegradable Mulches in AgricultureCurrent UIFA-SCRI Project: Oct 1, 2009-Sep 30 , 2012
To assess agricultural, ecological, and economic consequences of using biodegradable mulches in protected (High Tunnel) and Open Field specialty crop production systems Open Field specialty crop production systems.
To test Poly(Lactic Acid)- [PLA-]Based Nonwovens (spunbondO
and meltblown) as mulch prototypes.
To test PLA and commercial “biodegradable” mulches for their
O
O
n To test PLA and commercial biodegradable mulches for their
performance in growing tomatoes under High Tunnel and open field conditions at 3 different US sites .. in a controlled study
Provide data that may be useful for developing a standard for biodegradation of mulches .. (“inherent biodegradation” of g ( gcompostable plastics, ASTM D 6400 / D5988, is not robust)
Sites for Investigation Washington State University, Mount Vernon and Pullman
Campuses
Texas A&M / Texas Tech University, Lubbock, TX
University of Tennessee, Knoxville, TN
2
SCRI Interdisciplinary Research Team Materials Working Group, “WG” (UTK, WSU)
Design new biodegradable mulches from PLA and its biopolymer blends via Nonwovens textile technology
Physico-Chemical Testing
Crops WG (WSU, UTK, TAMU/TTU) Assess use of biodegradable mulches in high tunnels for specialty crops g g p y p
production systems: plant physiology, weeds, pests, & diseases
Outreach to specialty crop grower / organic farming community
Soils WG (WSU, UTK, TAMU)( ) Assess the impact of biodegradable mulches on soil ecosystem
Economics WG (WSU, TTU) Assess the economic impact of biodegradable mulches in high tunnels & its Assess the economic impact of biodegradable mulches in high tunnels & its
impact on sustainability: life cycle assessment.
Sociology WG (WSU, UTK) Better understand the needs and concerns of the specialty crops grower / Better understand the needs and concerns of the specialty crops grower /
organic farming community
Key Scientific Advisors and StakeholdersJ h D John Dorgan, Site Director, Colorado Center for Biofuels and Biorefining (C2B2), Department of Chemical Engineering; Colorado School of Mines, g g; ,Golden, CO
Ramani Narayan, Department of Chemical Engineering and Materials Science; Michigan State University, 2527 Engineering Building, East Lansing, MI
Robert Green NatureWorks LLC 402 Sir Walker Robert Green, NatureWorks LLC, 402 Sir Walker Lane, Cary, NC
Terry Phillips, Mark Williams, BioBag USA, Palm y p , , g ,Harbor, FL
Several members of the Specialty Crops Grower / O i F i C i f WA TX d TNOrganic Farming Community of WA, TX, and TN
High Tunnel and Field Studies of Biodegradable Mulches for Specialty Crops
Mulches BioBag (Starch-Based), Palm Harbor, FL
Bi T l (St h B d) D b i A i ti W t f d O t i BioTelo, (Starch-Based), Dubois Agrinovation, Waterford, Ontario
Spunbond PLA PLA donated by NatureWorks, Blair NE; made at Saxon Textile Institute, Germany, white, 90 g m-2
Black Plastic Polyethylene, Pliant Corp, Schaumburg., IL
Control (no mulch)
C ll l C t l “W dG dPl ” S Shi P C LLC Cellulose Control, “WeedGuardPlus,” SunShine Paper Company, LLC, Denver, CO, 107 g m-2
Conditions Mulches laid 12 ft long, 2 ft wide and 5 ft apart in high tunnels or open fields
Tomatoes planted: ~April – September, 2010
Irrigated: 1 inch of water per week
Continuous monitoring of soil & air temperature, moisture, etc.
Why PLA-Based Nonwovens as Mulches?
PLA: Biobased, Commercially available, reasonably priced, compostable & biodegradable
PLA: monomer is a common metabolite
Nonwovens: High strength, low weight
Nonwovens: Small fiber size Increased rate of hydrolysis
Nonwovens can be made inexpensively
High Tunnels at WSU-Mt. Vernon
High Tunnels at Univ. Tennessee
Greenhouse Studies of BDMsGreenhouse Studies of BDMs 3 Mulches (SB-PLA, MB-PLA,
Cellulose)Cellulose)
3 Soil Treatments (Manure, Lime, Control)
2 Durations (10 wk, 29 wk)
3 Replicates
Mulches Buried 2 cm below surface of soilof soil
Soil from a certified organic farm
1.0 L of Water per tray per 48 h p y pperiod
Performance of PLA Nonwoven Mulches: Greenhouse Studies SB PLA 14 8 ± 0 8Greenhouse Studies Spunbond PLA (SP-PLA)M = 132 000; PDI = 1 5
SB-PLA: 14.8 ± 0.8 m
Mn 132,000; PDI 1.5
Meltblown PLA (MB-PLA)Mn = 111,000, PDI = 1.5
Cellulosic Mulch
Cellulose: 20 8 ± 8 1 m MB-PLA: 6.3 ± 2.3 mCellulose: 20.8 ± 8.1 m MB PLA: 6.3 ± 2.3 m
Degradation of MB-PLA Mulches: Lime Treatment
10 weeks| 29 Weeks
Properties of Cellulosic Mulch which Nearly Disappeared after 10 Weeks in All Soil TreatmentsDisappeared after 10 Weeks in All Soil Treatments
Measurement Method 0 wk
Mass, g m-2 ASTM D3776
110.27 ± 4.66
Thickness, mm ASTM D1777
0.254 ± 0.007
Air Permeability, cm3 s 2
ASTM D737
0.72 ± 0.28cm-2 D737
Breaking Load ASTM D4632
50.54 ± 21.29
Breaking Elongation ASTM D5035
3.88 ± 0.44
Mn, kDa GPC Not Determined
Degradation of MB-PLA Mulch after 10 Weeksg
Measurement Method 0 wk 10 wk, Control
10 wk, Lime
10 wkManure
Mass, g m-2 ASTM D3776
82.89 ±7.69
97.71 ±7.57
96.66 ±9.72
101.56 ±9.08
Thickness, mm ASTM D1777
0.460 ±0.028
0.666 ±0.109
0.679 ±0.111
0.674 ±0.093
Air Permeability, cm3 s ASTM 35.2 ± 3.1 56.2 ± 14.4 Not Tested Not Testedcm-2 D737
Breaking Load ASTM D4632
5.23 ± 2.65 2.05 ± 1.26 0.88 ± 0.51 1.07 ± 0.76D4632
Breaking Elongation ASTM D5035
6.71 ± 4.30 4.16 ± 3.20 3.82 ± 1.96 4.26 ± 2.88
Degradation of SB-PLA Mulch after 10 Weeksg
Measurement Method 0 wk 10 wk, Control
10 wk, Lime
29 wk Manure
Mass, g m-2 ASTM D3776
91.06 ±2.84
112.87 ±3.26
108.50 ±5.80
108.47 ±3.58
Thickness, mm ASTM D1777
0.657 ±0.015
0.814 ±0.057
0.814 ±0.066
0.891 ±0.078
Air Permeability, cm3 s ASTM 96.2 ± 5.31 83.4 ± 6.58 90.1 ± 9.11 89.3 ± 6.93cm-2 D737
Breaking Load ASTM D4632
9.00 ± 1.38 10.25 ±0.90
10.05 ±1.00
9.68 ± 1.25D4632 0.90 1.00
Breaking Elongation ASTM D5035
11.13 ±1.06
11.05 ±0.82
10.77 ±1.42
11.24 ±1.29
Degradation of SB-PLA Mulch after 29 Weeksg
Measurement Method 0 wk 29 wk, Control
29 wk, Lime
29 wkManure
Mass, g m-2 ASTM D3776
91.06 ±2.84
Thickness, mm ASTM D1777
0.657 ±0.013
0.872 ±0.093
0.914 ±0.087
0.892 ±0.087
Air Permeability, cm3 s ASTM 96.2 ± 5.31 75.49 ± 75.44 ± 67.36 ±cm-2 D737 8.99 7.42 10.77
Breaking Load ASTM D4632
9.00 ± 1.38 2.25 ± 0.27 2.13 ± 0.32 2.24 ± 0.27D4632
Breaking Elongation ASTM D5035
11.13 ±1.06
9.25 ± 1.26 8.41 ± 2.58 9.39 ± 1.47
Summary
Cellulose control nearly disappeared after 10 wksMB PLA, as shown by physical strength testing
had appreciable degradation after 10 weeks in the l li d d il b h d h control, lime and manure treated soil but had the
greatest degradation in lime, followed by the manure compostmanure compost.
SB PLA did not have any loss in physical strength after 10 weeks but had appreciable strength loss after 10 weeks but had appreciable strength loss after 29 weeks in the control, lime and manure treated soil.
AcknowledgmentsDebra Inglis and Carol Miles (Project Directors)1;
C t B A d C bi A E i l A d d K L T M h d T W lt 1Curt Beus, Andrew Corbin, Ana Espinola‐Arredondo, Karen Leonas, Tom Marsh and Tom Walters1; Doug Hayes, Bobby Jones, Jaehoon Lee, Larry Wadsworth and Annette Wszelaki2;
Eric Belasco and Jennifer Moore‐Kucera3; Russ Wallace4; and, Marian Brodhagen5
NatureWorks (PLA Donation)Saxon Textile Institute (Germany)
Biax Fiberfilm (WI USA)D Willi Kli (UTK)Dr. William Klingeman (UTK)
Phil Flanagan (UTK)
1 2 3 4 5
SCRI‐SREP Grant Award
No. 2009‐02484