EXPANDING THE POSSIBILITIES: - The University of Tennessee

High tunnel production of specialty
vegetables offers growers the
opportunity for additional income
and provides consumers year-round
access to local produce
and overwintered cover crops for early-season organic broccoli
production. Living mulches provided the greatest ground
coverage when cover crop establishment was poor; however,
when cover crops produced a large amount of biomass, living
mulch establishment was suppressed. Decreases in herbivorous
pests and suppression of grassy and cool-season weed species
were also observed. Decreases in crop growth and biomass were
observed, however, indicating reductions in crop vigor and yield
may be expected with the implementation of strip tillage and
living mulch crops. This project was conducted in 2009-2010.
High tunnel tomato production: Evaluating heirloom
and hybrid varieties for early‐season availability
(Wszelaki, Rogers)
High tunnels allow growers in temperate regions to expand the
growing season through low- cost environmental modification.
Tomato is high value specialty crop well suited to high tunnel
production. The objective of this study was to determine
the impacts of high tunnel production and planting date on
heirloom and hybrid tomato varieties by observing differences in
plant growth, yield, marketability and early blight development
within an organic production system. The results showed that
high tunnels increased marketability and size of tomatoes,
and reduced defoliation resulting from early blight. Tomato
planted earlier in both high tunnels and open field yielded
more marketable fruit during the production season than plants
established on later planting dates. Hybrid varieties yielded
more marketable fruit than heirloom varieties; however, heirloom
tomatoes can have equivalent market value because of greater
consumer demand and premium prices attained in the local
market. This project was conducted 2009-2010.
Biofumigation with mustard meal to reduce soilborne
diseases in pumpkin (PREC) (Wszelaki, Sams)
Tennessee has consistently ranked among the Top 10 pumpkin
producing states in the U.S. However, many Tennessee growers
have quit growing pumpkins on their land due to Plectosporium
Blight, caused by the fungus Plectosporium tabacinum.
Biofumigant crops produce secondary plant products that might
have beneficial effect in managing plant pests.
Biofumigation could help to control Plectosporium and allow
TN producers to continue to grow pumpkins, as well as reduce
weed pressure in pumpkin fields. The objective of this study
was to compare weed and disease suppression, yield, and
fruit postharvest fruit quality and storability of pumpkins under
standard fumigation and biofumigation treatments. This project
was conducted in 2010.
Trap cropping of cucumber beetles and squash
stink bugs for low‐input melon production
(Wszelaki, Rogers)
Trap cropping is the planting of a ‘trap’ crop to protect the
main cash crop from particular pests, by luring them into the
trap. In this study, eight varieties of cucurbits were assessed
as trap crops to reduce cucumber beetles and squash bugs in
cash crops (cucumber and cantaloupe). Varieties tested were
cucumber ‘Dasher II’ (also grown as cash crop), cantaloupe
‘Atlantis’ (also grown as cash crop), pumpkin ‘Moonshine’, yellow
straightneck squash ‘Goldbar’, galia melon ‘Diplomat’, winter
squash ‘Green-Striped Cushaw’, gourd ‘Mini Red Turban’ and
‘Blue Hubbard’ squash. The results showed that both cucumber
beetles and squash bugs were 30 and 15% less prevalent,
respectively, on cash crops than on trap crops. The highest
numbers of cucumber beetles were found on ‘Diplomat’ galia
melon and ‘Mini Red Turban’ gourd and the highest numbers
of squash bugs were found on ‘Goldbar’ and ‘Blue Hubbard’
squash and ‘Moonshine’ pumpkins. The establishment of
perimeter trap crops can prevent insect damage on cash crops.
Future studies are needed to test organic methods for pest
management on the trap crops. This was a collaborative project
with Appalachian Sustainable Development and Virginia Tech
funded by the EPA and conducted in 2010.
Small farm composting system demonstration
(Wszelaki, Rogers)
Small to medium sized organic growers rely on compost
and other organic amendments to increase soil fertility. The
objective of this demonstration project was to replicate a
low-cost three-bin compost system following plans developed
from the University of California Cooperative Extension Service.
Results showed that although the three-bin system was easy
to construct, improvements are needed due to warping and
weathering of un-treated lumber, required in certified organic
systems. Piles need to be turned on a regular basis, and the
proper C/N ratio is difficult to maintain in the static piles. The
amount of compost obtained from the three-bin system is more
appropriate for a homeowner garden than a commercial farm;
consequently we recommend windrow composting systems.
This project was started in 2010.
Potential of biodegradable mulches for specialty crops
produced under protective covers (Wszelaki, Martin,
Hayes, Lee)
This transdisciplinary research and Extension project on
Biodegradable Mulches for Specialty Crops Produced
Under Protective Covers, funded by NIFA’s SCRI program,
is determining whether experimental spunbond nonwovens
and leading commercially-available biodegradable mulches
are of similar quality to conventional black plastic in both
high tunnel and open field specialty crop production, and
can safely biodegrade in the soil. In this 3-year study, a team
of 17 scientists is evaluating biodegradable mulches in a
tomato production system in three diverse regions of the U.S.:
eastern Tennessee, central Texas, and western Washington. In
addition, the team is evaluating the adaptability of six lettuce,
strawberry and tomato cultivars to high tunnel production in
these contrasting environments. In Tennessee, winter strawberry
production has been shown to be a viable option for high tunnel
growers. This project began in 2010 and is on-going.
Evaluation and optimization of anaerobic soil
disinfestation for Tennessee (Butler, Ownley, Wszelaki)
Soil treatment by anaerobic soil disinfestation (ASD) is an
alternative to soil fumigation with chemicals such as methyl
bromide. Treatment by ASD involves the addition of a labile
carbon (C) source to the soil (to stimulate rapid microbial growth
and respiration), tarping with plastic to limit gas exchange, and
irrigation to saturation of the topsoil (or raised-bed) to flush soil
pore space (i.e., not “flooding”). Pathogen, nematode, and
weed control are achieved in part due to the creation of organic
acids (e.g. acetic, butyric) by the anaerobic decomposition of
the added C source as well as the lack of available oxygen,
biocontrol by anaerobic microorganisms, and the formation of
volatile compounds. To begin the process of evaluating and
optimizing ASD for Tennessee and other similar production
regions, the goals of this project are to:
1. evaluate soil temperature and carbon source impacts on
pathogen and weed control during ASD treatment in a
series of growth chamber and greenhouse experiments,
2. evaluate carbon sources for ASD treatment impacts on
pathogens, weeds, crop performance, and soil properties
in a replicated field experiment, and
3. demonstrate optimized ASD methods versus grower
standard chemical controls.
If the ASD system can be successfully optimized for Tennessee
production systems, it will provide conventional Tennessee
specialty crop producers with a tool they can use to eliminate
the use of soil fumigants in their production systems and will
provide organic growers with a tool to reduce pest pressure
in their production systems. This project is funded in part by
USDA-NIFA Methyl Bromide Transitions Program. This project
began in 2010.
24 Expanding the Possibilities: UT-TDA Organic and Marketing Initiative
University of Tennessee
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