Optimizing anaerobic soil disinfestation for Tennessee · • Tomato and bell pepper • Soil...
Transcript of Optimizing anaerobic soil disinfestation for Tennessee · • Tomato and bell pepper • Soil...
Optimizing anaerobic soil
disinfestation for Tennessee
D.M. Butler*, S.E. Eichler Inwood, D.G. McCarty, C.E. Sams and A.L.
Wszelaki, Dept. of Plant Sciences, Univ. of Tennessee, Knoxville, TN
B.H. Ownley and M.E. Dee, Dept. of Entomology and Plant
Pathology, Univ. of Tennessee, Knoxville, TN
N. Kokalis-Burelle and E.N. Rosskopf, USDA-ARS, Fort Pierce, FL
Background
• Developed as an alternative to soil
fumigation in the Netherlands and Japan
• Demonstrated control in diverse locations
for a range of soilborne plant pathogens
and plant-parasitic nematodes
(photos: J. Muramoto, D.M. Butler, S.E. Eichler Inwood)
ASD treatment steps
1. Incorporate easily-decomposable organic material
– Provides carbon source for soil microbes
2. Tarping with polyethylene mulch
– Prevents resupply of oxygen
– Allows volatile compounds to accumulate
– Can increase soil temperature
3. Irrigate to saturation of topsoil
– “Flush” air-filled pore space
– Provide adequate moisture for microbial growth
ASD treatment
• Rapid growth of soil microbes depletes
soil oxygen
• Resupply of oxygen limited by high soil
moisture content and tarp
• Soil microbial community shifts towards
anaerobic microorganisms
• Anaerobic condition persists until C
source utilized and/or soil moisture
content drops (typically 1 to 2 weeks)
ASD mechanisms of control
• Toxic by-products of anaerobic
decomposition
– Organic acids (e.g. acetic, n-butyric)
– Volatile compounds
• Reduced metal ions (e.g. Fe2+)
• Biocontrol by soil microorganisms
• Heating by solarization (if applicable)
• Additive or interactive effects of the above
ASD for Tennessee
• Considerable progress adapting technology
to FL vegetable (e.g., Butler et al., 2012a;
Rosskopf et al., 2012) & CA strawberry
production (e.g., Shennan et al., 2011; 2012)
• Need to evaluate and optimize for other
production regions in the country
– C amendments
– Environmental conditions
– Soil types
– Cropping systems/seasonality
Tennessee production systems
• Recent CUEs: tomato, pepper,
cucurbits, strawberry
• In contrast to FL vegetable production
systems:
– Winter fallow
– Fumigation primarily occurs in mid-spring
– Soil temperatures range from 15 to 25 C at
a 10 to 15-cm soil depth under black PE
mulch
C source amendments and rates • California
– Rice bran (4.5 to 9 t/acre; ~5.5 to 11 mg C g-1 soil)
– Mustard cake, mustard seed meal, ethanol
• Florida – Liquid molasses (3.5 t dry matter/acre,
~4.5 mg C g-1 soil in raised bed)
– Cover crop residue (variable)
• Tennessee – Dry molasses (~1.3 to 2.5 t/acre, 1 to
2 mg C g-1 soil)
– Cover crop residue (variable, 1 to 4.2 mg C g-1 soil)
– Future work: wheat bran
(photos: J. Muramoto, E.N. Rosskopf, D.M. Butler)
Objectives
1. Evaluate soil temperature and C
impacts on pathogen and weed control
during ASD (controlled environment)
2. Evaluate C source impacts on
pathogens, weeds, crop performance,
and soil properties in a field experiment
3. Demonstrate ASD methods versus
grower standard chemical controls
Controlled environment studies
• Pathogens
– Rhizoctonia solani
– Sclerotinia
sclerotiorum
• Soil temperatures
– 15 C to 24 C
• C-source treatments
– Crimson clover
– Hairy vetch
– Cereal rye
– Wheat
– Mustard
– Arugula
– Fallow control
• Low C amendment rates
– Approximately 1 mg C g-1 soil
• Rhizoctonia solani
– Control in ASD treatments not significantly
better than control
• Sclerotinia sclerotiorum
– High sclerotial germination in all treatments
(75 to 100%)
Controlled environment studies
Controlled environment studies
• Pathogens/weeds
– Sclerotium rolfsii
– Yellow nutsedge
• Soil temperatures
– 15 C to 24 C
• C rates
– 1 to 2.7 mg C g-1 soil
• C-source treatments – Untreated control
– Biofumigant control
(Mustard seed meal; 2 t/ac)
– Fallow with dried molasses
(2.5 t/ac)
– Mustard /arugula cover crop
– Mustard/arugula +
molasses
– Cereal rye cover crop
– Cereal rye + molasses
– Crimson clover cover crop
– Hairy Vetch cover crop
– Wheat cover crop
Controlled environment studies
(McCarty, 2012)
(McCarty, 2012)
(McCarty, 2012)
(McCarty, 2012)
Controlled environment studies
• Pathogens/
nematodes
– Fusarium oxysporum
– Southern root-knot
nematode
• Soil temperatures
– 15 C to 25 C
– 25 C to 35 C
– 35 C to 45 C
• C-source treatments – 0 mg C g-1 soil
– 1 mg C g-1 soil
– 2 mg C g-1 soil
– 3 mg C g-1 soil
– 4 mg C g-1 soil
• Mixtures of starch and
glucose
• Amendment rates as high as 4 mg C g-1 soil
may be necessary to control F. oxysporum at
lower soil temperatures
• Unclear whether this holds true for other
pathogens of concern
• Past research of cover crop amendments at
20 to 30 C indicated effectiveness for control
of F. oxysporum, S. rolfsii and M. incognita at
low amendment rates (Butler et al., 2012b)
Controlled environment studies
Objectives
1. Evaluate soil temperature and C
impacts on pathogen and weed control
during ASD (controlled environment)
2. Evaluate C source impacts on
pathogens, weeds, crop performance,
and soil properties in a field experiment
3. Demonstrate ASD methods versus
grower standard chemical controls
Field trial
• Soil texture: clay loam
• Late Mar/early Apr
treatments
• 5-cm irrigation
• Standard black PE
• Tomato and bell pepper
• Soil temperatures 15 to
24 C
• ASD C rates 1.0 to 4.2
mg C g-1 soil
• C-source treatments – Untreated control
– Biofumigant control
(MSM, 2 t/acre)
– Fallow with dried
molasses (2.5 t/acre)
– Mustard /arugula
cover crop mixture
– Mustard/arugula +
molasses
– Cereal rye cover crop
– Cereal rye + molasses
(McCarty, 2012)
(McCarty, 2012)
Field trial
• Initial field studies in TN have been promising
• High accumulations of anaerobic soil
conditions, especially during the second year
of treatments
• In the second year, lower R. solani
populations were observed in several ASD
treatments compared to UTC although only
significantly so with a mustard/arugula cover
crop
Field trial
• Correlation of accumulated anaerobic
conditions to pathogen and weed control was
not observed
• Tomato and bell pepper yields following ASD
treatment generally did not differ significantly
among treatments
• Low pest pressure observed in field
• Additional research field trials in 2013-14
Objectives
1. Evaluate soil temperature and C
impacts on pathogen and weed control
during ASD (controlled environment)
2. Evaluate C source impacts on
pathogens, weeds, crop performance,
and soil properties in a field experiment
3. Demonstrate ASD methods versus
grower standard chemical controls
On-farm trials and demonstrations
On-farm trials and demonstrations
On-farm trials and demonstrations
(photo: D.M. Butler)
On-farm trials and demonstrations
Indicator of reduction in soils (IRIS)
Conclusions
• Optimization of ASD in Tennessee is in
early phases
– C rates at or above 4 mg C g-1 soil likely
needed due to cooler soil temperatures in
spring treatments
– N fertility management post ASD
• Vegetable producers unlikely to see N limitation
• Fertility for strawberry post ASD needs further
research and more active management
Conclusions
• Optimization of ASD in Tennessee is in
early phases
– Indication of increased activity of
Trichoderma spp. post treatment
– Indication of ASD treatment activity against
monocot weeds
– No yield differences observed in vegetables
– Need more research on sites with high pest
pressure
Ongoing work
• Research farm trials with varying C
rates & C:N ratios + fumigant control
• Increased on-farm research &
demonstration activities
• Continued controlled-environment pot
studies
Acknowledgements
• Partial funding by USDA-NIFA grant
2010-51102- 21707
References • D.M. Butler, N. Kokalis-Burelle, J. Muramoto, C. Shennan, T.G. McCollum and
E.N. Rosskopf . 2012a. Impact of anaerobic soil disinfestation combined with soil
solarization on plant–parasitic nematodes and introduced inoculum of soilborne
plant pathogens in raised-bed vegetable production. Crop Protect. 39, 33-40.
• D.M. Butler, E.N. Rosskopf , N Kokalis-Burelle, J.P. Albano, J. Muramoto and C.
Shennan. 2012b. Exploring warm-season cover crops as carbon sources for
anaerobic soil disinfestation (ASD). Plant Soil 355, 149-165.
• D.G. McCarty. 2012. Evaluation of anaerobic soil disinfestation (ASD) as a
fumigant alternative for warm-season vegetable production in Tennessee. M.S.
Thesis, University of Tennessee.
• E.N. Rosskopf, N Kokalis-Burelle, J. Hong, and D.M. Butler. 2012. Status of
ASD development in Florida. Proc. Annual Int. Res. Conference on Methyl Bromide
Alternatives and Emissions Reductions. MBAO, p. 15.1-15.2, .
• C. Shennan, J. Muramoto, G. Baird, O. Daugovish, S. Koike and M. Bolda.
2011. Anaerobic soil disinfestation: California. Proc. Annual Int. Res. Conference on
Methyl Bromide Alternatives and Emissions Reductions. MBAO, p. 44.1-44.4.
• C. Shennan, J. Muramoto, G. Baird, S. Fennimore, S. Koike, M. Bolda, O.
Daugovish, and S. Dara. 2012. Non-fumigant strategies for soilborne disease
control in California strawberry production systems. Proc. Annual Int. Res.
Conference on Methyl Bromide Alternatives and Emissions Reductions. MBAO, p.
16.1-16.4.