Biodegradable Mulches for Specialty Crops Produced
Under Protective Covers
Crops Working Group
Progress Report
Annette Wszelaki and Jeff Martin, TN
Russ Wallace and Joel Webb, TX
Carol Miles, Tom Walters, Debbie Inglis,
Jonathan Roozen, Babette Gundersen,
Jacky King and Jeremy Cowan, WA
Key objectives:
•Evaluate high-value crops commonly used in high tunnel
production in relation to productivity, environmental
conditions, pest/disease threats, and profitability.
•Evaluate tomatoes grown in HT versus open field settings
with five BDM treatments and a bareground control.
•Study BDMs in greenhouse and field settings in terms of
impacts on soil ecology and root health as well as meeting
ASTM (and grower) standards for bio-degradability.
•Ascertain economic costs and benefits of HT and BDM use.
•Identify barriers and bridges to HT and BDM adaptation
through focus groups.
Wind and blowing dust causes
weathering on TX tunnels- making
them appear to be years older than
they really are!
Wind damage to WA tunnels in 2010
Come hail…
Hail Damage in Tennessee in April 2011
Crops Working Group Progress Report
…or high water!
Flooding in Texas in 2010
Lettuce Cultivars 2010
Adriana (Butterhead/Boston)
Coastal Star (Romaine)
Ermosa (Butterhead/Boston)
Greenstar (Greenleaf)
Jericho (Romaine)
New Redfire (Redleaf)
TN Lettuce Results
• Both total (number and weight) and
marketable yield (weight) differed significantly
among varieties and between HT and OF
locations.
• Total yields were higher in HT, while
marketable yields were higher in OF, due to
bolting.
• Coastal Star had significantly higher
marketable yield (by weight) than all other
varieties.
TX Lettuce Results
• Significant V x L interactions were observed for
yield and DTH.
• Also significant varietal differences for all
variables except total plant number.
• Within HT, Romaines had significantly higher total
plant weight compared to the other four
varieties.
• In the OF, Jericho, Coastal Star and Green Star
had the highest weights.
• The number of marketable plants/plot in HT did
not differ, while in the OF Butterheads had fewer
marketable plants, due to increased bolting.
WA Lettuce Results
• Lettuce yield was not different due to cultivar or
location (HT and OF) except that head height, head
diameter and core length were greater in the HT.
• Days to harvest were 1 day less in the HT compared to
OF, and the earliest maturing cultivar was Green Star
(56 DAT) and Jericho and Adriana were the latest
(61.25 DAT), but differences were NS.
• The relatively cool mild temperatures in NW WA did
not induce bolting; however, if temperatures are too
cool and rainfall is somewhat high, disease pressure
(i.e., Botrytis) and slugs may become an issue.
Tip Burn
Sclerotinia
Tomato Cultivars 2010
Celebrity (Determinate)
Cherokee Purple (Indeterminate)
Early Girl (Indeterminate)
Red Brandywine (Indeterminate)
Stupice (Indeterminate)
Oregon Spring (Determinate)
Red Defender (Determinate)
Homestead 24 (Determinate)
Strawberry Cultivars Fall 2010
Albion (Everbearing, Bareroot and Plugs)
San Andreas (Everbearing, Bareroot)
Chandler (June Bearing, Plugs)
LCN (June Bearing, Plugs)
Strawberry Festival (June Bearing, Plugs)
TN Strawberry Results
•2010 Spring Planting- temperatures got too hot, too fast
•2011 Harvests:
•High Tunnels (HT) started March 23… still going.
•Open Field (OF) started April 15 and done in by hail
on April 27.
•Fall planting much better suited to TN climate.
•Higher quality and yields of berries in HT.
•Hail caused damage both inside and outside; HT
plants rebounded, OF did not
•Strawberry Festival and Albion (Plugs) top yielders in
both HT and OF
•Poor pollination, insect damage and leather rot top 3
reasons for unmarketable fruit
TX Strawberry Results
•Harvests:
•High Tunnels (HT) –over 30 harvest (Feb. 21).
•Open Field (OF) –15 harvests (Apr. 5) .
•Opposite response to spring planting vs. fall
planting.
•Production:
•Higher quality and yields of berries in HT.
•OF plots hailed on causing damage to plants.
•Increased bird and rodent damage to OF.
•Early populations of mites & aphids in HT that
needed to be controlled.
•Botrytis infected most berries in storage study.
WA Strawberry Results
•Strawberry total yields were comparable in HT and OF,
but marketable yield was greater and culls were less in
HTs; culls accounted for 29% of the berries in HTs, and
for 46% of the berries in OF; there were fewer overripe
and damaged fruit in HTs.
•‘Seascape’ produced more marketable berries and
more culls than ‘San Andreas’ or ‘Albion’ in both HT and
OF.
•Type III Bronzing was the most common cause of
culled strawberry fruit; catfacing was also common,
and in OF ‘Seascape’ had the highest levels; Botrytis
and water damage occurred in OF but not HT.
Product
BioBag AgFilm
Company
BioBag; Palm
Harbor, FL
BioTelo Agri Dubois Agrinovation;
Waterford, ON, CAN
Spunbond
nonwoven
Saxon, GER;
NatureWorks LLC,
Blair, NE
Black Plastic, Pliant Corp.;
1.0 mil
Schaumburg, IL
Weed Guard Sunshine Paper Co.
Plus
LLC; Aurora, CO
Non-mulch, bareground control
Mulch Content
Cornstarch and non-disclosed
biopolymers, biodegradable
& compostable
100% PLA
Standard polyethylene,
agricultural plastic control
Cellulosic, biodegradable
control
TN BDM Results
• Degradation took place more slowly in HT versus OF.
• Spunbond and the traditional black plastic mulches showed
very little degradation in both the high tunnel and open
field plots.
• Both of the cornstarch based mulches (BioBag and BioTelo)
showed significant visual degradation in the tunnels and
open field by the final evaluation date in August.
• The cellulose control degraded similarly to the BioBag in
the open field, but degraded more slowly inside the
tunnels, likely due to the protection from wind and rain
that the tunnels provide.
• Weed count was significantly greater in the HT than in the
OF at Time 2 but not at Time 3.
• The greatest # and weight of weeds were in the Spunbond
treatment, while for all other treatments, weed # and
weight were significantly less and statistically equivalent.
TX BDM Results
• Experimental Spunbond material and the polyethylene black plastic
did not show signs of degradation (Rips, Tears and Holes (RTH))
either in the HT or OF plots.
• Therefore, the spunbond mulch would not likely be considered a
good alternative to polyethylene black plastic in terms of
decreasing grower’s labor and disposal costs for mulch removal
• BioBag, BioTelo and WeedGuard Plus showed significant surface
degradation (RTH) by Oct 8, and the average rate was higher in the
OF compared to HT environment.
• While the numbers of RTH in HT compared to OF plots on Oct 8
were to some degree similar, the associated %SAE was much
greater in OF compared to HT plots.
• BioBag and BioTelo still required removal by hand both inside the
HT and in the OF.
• In spring 2011, during land prep, small and large pieces of all the
mulches except WeedGuard Plus were found, suggesting that more
rapid degradation is needed to eliminate hand removal, especially
when used under high tunnel production on the TX High Plains.
Pieces of BDMs found in TX plots on May 16
No evidence WeedGuardPlus
WA BDM Results
• Total # and weight of ‘Celebrity’ tomato fruit were less in
bareground and Spunbond than in BioBag and BioTelo treatments.
• Tomato fruit cracking was least in the bareground treatment.
• M x L interaction for number of tears and visual assessment of
degradation; spunbond and black plastic mulch had the least
degradation assessed visually in both HT and OF while BioTelo and
cellulose control had the most; visual degradation was 2-4 times
greater in OF than in HT for all treatments.
• Weeds did not differ between HT and OF; weed # and weight were
significantly greater in Spunbond mulch than in all other mulch
treatments.
• In OF, black plastic mulch tended to have less soil moisture than the
other treatments; in HT, bareground tended to dry out more rapidly
and had more pronounced wet/dry cycles.
Hot Topics
• Reviewing and/or tweaking protocols for crop
harvest and quality assessment (tomato grading
in particular), and for weed, disease, insect and
environmental monitoring
• Plan for manuscripts and writing assignments
• Strawberry cultivar selection and procurement
• What other sorts of weather events can the
tunnels endure?