Improving Drip Fumigation for Strawberry Production in California

Ruijun Qin, Oleg Daugovish, Suduan Gao, James Gerik, Tom Gordon, Husein Ajwa &

Brad Hanson

Major issues on drip fumigation practice− High emissions occur in PE tarped field − Air quality

issues.

Field trial in Oxnard 2006:Drip fumigation (1,3-D & CP) at 2”.

300 lbs/ac Inline (61% 1,3-D, 33% CP).

Major issues on drip fumigation practice− High emissions occur in PE tarped field − Air quality

issues.− Unsatisfactory pest control.

Increasing number of pathogen-infested fields. Difficulty in controlling pests at bed-center or shoulder, especially

at deeper depth. Weed problem.

New plastic films

− Low permeability film (LPF): − Virtually Impermeable Film (VIF)– Totally Impermeable Film (TIF)

TIF

VIF

Field trial in Oxnard 2009

Proposed solutions− Low permeability film (LPF) covering:

− Increasing drip line number:

Traditionalway

New strategies

PE film with 2 drip lines

LPF with 4 drip lines

– Bed configuration: 45” (width), 16” (height).

– Traditional drip-line depths: 2”.– Parallel 4 dripping line (2” deep)– Two shallow (2”) plus 2 deep (7”)

dripping lines. – Fumigant rate: full rate vs. half rate.– Film type: PE vs LPF. – Soil type: sandy loam.

2013 Camarillo Trial

2014 Oxnard Trial 2015 Oxnard Trial

• Installing drip tapes:

2 outer drip tapes for fumigation

4 parallel drip tapes2 shallow + 2 deep drip tapes

Results

• Fumigant emissions• Fumigant distribution• Pest control • Strawberry production

Emissionsfromtarpedbeds(2015Oxnardtrial)

TIF tarping << PE tarping. Drip tape layout did not

impact emission.

Tri-Clor Fumigant 200 lbs/ac

Emissionsfromtarpedbeds(2014Oxnardtrial)

VIF tarping << PE tarping. Drip tape layout did not

impact emission.

Tri-Clor Fumigant 224 lbs/ac

Emissions from TIF tarped bed(2013Camarillotrial)

Deep-application had much less emission than shallow-application. High emission from TIF was due to flaw during manufacture.

Pic-Clor 60 EC (a mixture of 57% CP, 37% 1,3-D) Full rate: 300 lbs/ac

Emissions from uncovered furrow

Trace level regardless of treatments:• Long distance from drip tape to furrow• Soil compaction at furrow• Mostly covered by extended film

Results

• Fumigant emissions• Fumigant distribution• Pest control • Strawberry production

Fumigant distribution in soil profile

− In soil profile– Bed center: 4”18”– Bed edge: 4”18”

Concentration-time index (CT) (g cm-3 h)

- An indicator for pest control result. - Higher CT means better pest control.

Critical CT value of chloropicrin for pest controlWeeds/Pathogens/Nematodes CT (g cm-3 h)Knotweed (Polygonum arenastrum) 74Chickweed (Stellaria media) 208Purslane (Portulaca oleracea) 208Little Mallow (Malva parviflora) NARedstem Filaree (Erodium cicutarium) NAPythium ultimum 6Verticillium dahliae 348Phytophthora cactorum 142Fusarium oxysporum 142Citrus nematode (Tylenchulus semipenetrans Cobb) 10Rootknot nematode (Meloidogyne spp. Chitwood) 10

* The values for weeds and pathogens were calculated based on the data in Klose et al. (2007) with the fumigants as the mixture of 1,3-D and CP. The values for nematode was cited from Schneider et al. (2008) with the fumigant as CP.Schneider et al., 2008. HORTSCIENCE 43:1826–1832; Klose et al., 2007. Crop Protection 26: 535–542.

4L/full/TIF

Bed width (cm)

-40 -20 0 20 40

Soi

l dep

th (c

m)

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CT in 2015 Oxnard trial with Tri-Clor EC:full rate: 200 lbs/achalf rate: 100 lbs/ac

4L/half/TIF

Bed width (cm)

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oil d

epth

(cm

)

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2L/full/TIF

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2L/full/PE

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100150 200 250300350

CT value of 2014 Oxnard trial with

Tri-Clor EC Full rate: 224

lbs/ac

CT value is accumulated (fumigant concentration * fumigation time)

4L/full/VIF

Bed width (cm)

-40 -20 0 20 40S

oil d

epth

(cm

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2L/full/PE

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4L/half/VIF

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CT value of 2013 Camarillo trial with Pic-Clor 60 EC (a

mixture of 57% CP, 37% 1,3-D)

Full rate: 300 lbs/acCT value for CP in TIF/shallow/half

Bed width (cm)

-60 -40 -20 0 20 40 60

Soil

dept

h (c

m)

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CT value of CP in TIF/deep/half

Soil

dept

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CT value of CP in TIF/shallow/full

Bed width (cm)-60 -40 -20 0 20 40 60

Soil

dept

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CT value of CP in TIF/deep/full

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Results

• Fumigant emissions• Fumigant distribution• Pest control • Strawberry production

Spo

res

per g

ram

of s

oil

Location in bed

6” depth

12” depth

Four drip tapes:

Not detectable

two shallow (2.5”) + two deep (7”)

Fusarium survivorship (2015 trial)

Fusarium survivorship (2015 trial)

Pest control(2014 Oxnard trial)

Pre-buried nutsedge tubers. The occurrence of weeds at the holes where strawberry plants grow.

Pathogen disease occurred in control plots(2014 Oxnard trial)

• Pest control in TIF treatments (2013 trial)

Pre-buried Fusarium oxysporum: Detected in non-fumigated beds, especially at the

bed-center. All the fumigation treatments provided 100%

control, both at bed-center or near bed edge.

Pythium ox. in soil (near bed edge from 0-30 cm: Detected in non-fumigated beds. All fumigation treatments provided 100% control.

Results

• Fumigant emissions• Fumigant distribution• Pest control • Strawberry production

Marketable fruit yield: Jan-April2015 trial

Strawberryyield(2014Oxnardtrial)

VIF treatments showed a better yield during early season (December –March).

* The measurement was on 20 plants per beds.

• Marketable berry yields during early season were generally no difference.

* The measurement was on 20 plants per beds.

Strawberry yield(2013 Camarillo trial)

Summary on drip fumigation studies

− LPF covering and deep application can reduce fumigant emissions from tarped beds dramatically.

− Emission from furrow was not a concern in raised-beds systems.

− Higher emissions and poor pest control occurs in PE covered beds.

− Increasing drip line numbers, deep application, and LPF covering will be the optimized fumigation technology in raised-bed systems.

Acknowledgment• Grant from the California Department of Food and Agriculture

Specialty Crop Block Grant Program and from the Walmart Foundation and administered by the University of Arkansas System Division of Agriculture Center for Agricultural and Rural Sustainability.

• Cooperating growers, Steve Imoto, Glen Imoto, Henry Ito, and their field crew providing the tested field, field equipment, and field preparation.

• Crop Production Service (CPS), TriCal, Inc. provided fumigation service.

• Technical assistance was provided by Water Management Research Unit, USDA-ARS, Parlier, CA and the Department of Plant Sciences, UC Davis.

Ruijun (Ray) QINUniversity of California-Davis/ USDA-ARS 9611 S. Riverbend Ave., Parlier, CA 93648

Tel: 559-596-2904 Cell: 559-905-9286

Email: ruijun.qin@ars.usda.gov