N dynamics Following y gAnaerobic Soil Disinfestation

(ASD)(ASD)

J. Muramoto1, C. Shennan1, M. Zavatta1, G. Baird1, S.T. Koike2,M P Bolda2 K Klonsky3 and M Mazzola4M.P. Bolda , K. Klonsky and M. Mazzola

1 Department of Environmental Studies, University of California, Santa Cruz 2 U i i f C lif i C i E i 2 University of California, Cooperative Extension 3 Department of Agricultural and Resource Economics, University of California, Davis4 USDA-ARS, Tree Fruit Lab, Wenatchee, WA

Outline1. ASD Basics and Update

2 E 1 R t ti / t d d l/ASD2. Exp. 1: Rotation/mustard seed meal/ASD trials

….organic site and conventional site

3. Exp. 2: ASD carbon-source trialp

…..conventional site

ASD BasicsBiological alternative to fumigants developed in the Netherlands (Block et al., 2000) and Japanin the Netherlands (Block et al., 2000) and Japan (Shinmura et al., 2000)

Control a range of soilborne diseases gand enhance yield in many crops

Acid fermentation in anaerobic soilAcid fermentation in anaerobic soil

In CA, being optimized for strawberry and cane berriescane berries

being tested for strawberry nurseries, B l l d lBrussels sprout, almond, walnuts

ASD Process1. Incorporate readily available organic matter

P id C f il i bProvide C source for soil microbes

2.Cover with oxygen impermeable tarp

3. Irrigate to saturate soil then to maintain field capacityp y

Water-filled pore space

Create anaerobic conditions and stimulate anaerobic decomposition of incorporated organic materialincorporated organic material

Anaerobic Soil Disinfestation (ASD)(Shennan et al 2007)(Shennan et al., 2007)

1. Broadcast rice bran at 9 t /

1 29 tons/ac

2. Incorporate bran3. List beds4. Cover w/ plastic mulch5. Drip irrigate total 3 -5

ac-inches over 3 wks

3 4

ac inches over 3 wks6. Leave 3 wks and

monitor soil Eh and t

5 6temp

ASD-Treated Fields in California1200

)

2014-15Ventura/Oxnard

800

1000

ea (a

cres

)

623103

292Ventura/Oxnard

Santa Maria

400

600

eate

d ar

e 623103 Watsonville/ Salinas

0

200

400

ASD

-tre

•80% organic sites•20% conventional sites

0•~20% of CA organic strawberry acreages•~2 5% of CA total

(Farm Fuel Inc. Personal communication)

2.5% of CA total strawberry acreages

Potential MechanismsProduction of organic acids toxic to some pathogensProduction of volatiles toxic to some pathogensp gReduction of iron and manganese – Fe2+ and Mn2+ toxic to some pathogensShifts in microbial communities to create competition Shifts in microbial communities to create competition or antagonism that suppress pathogensLack of oxygen, low pH,C bi ti f th b ll i t l t d!Combination of the above – all interrelated!

How are each of these processes related to i f ifi th ?suppression of specific pathogens?

How are processes affected by C source used, soil moisture and temperature, and initial microbial community?

Summary of Findings to 2014 ~field trials~

Good yields obtained with 9 t/ac rice bran in field trials Good y e ds obta ed t 9 t/ac ce b a e d t a saveraged 99% (82 – 114%) of fumigant yields in 10 replicated field trials in Watsonville, Castroville, Salinas, Santa Maria, and Venturaand VenturaGot consistently good V. dahliae suppression; 80 to 100%  decrease in # microslerotia in soil, using 9 t/ac rice bran 

Weed suppression limited in the central coast of CAMay not need pre‐plant fertilizer with 6‐9 t/ac rice bran as C‐source but probably will with lower N sourcessource, but probably will with lower N sourcesMay provide excess N to strawberries with 9 t/ac rice bran

Need to monitor N dynamics!Need to monitor N dynamics!

Exp. 1: Rotation/Mustard seed meal/ASD trials

• Randomized block split plot designed field trials with 4 replicates at 2 sites (organic and conventional)4 replicates at 2 sites (organic and conventional)• Main plot: pre-crop of strawberry

• broccoli-strawberry-winter cover crop*-lettuce*y p• cauliflower-strawberry-winter cover crop*-lettuce*• fallow-strawberry-winter cover crop*-lettuce*

* O i l• Split plot: soil treatment for strawberries

• MC (B. juncea : S. alba = 1:1 weight) 1.5 t/ac

* Organic only

( j g )• ASD w/ rice bran 9 t/ac• MC 1.5t/ac + ASD w/ rice bran7.5t/ac

d h k (UTC)• untreated check (UTC)• fumigation w/ Pic-clor60** ** Conventional only

Block 1 Block 4

Organic site, UCSC Organic farm, Santa Cruz, CA. 5 ms/g soil

Block 1Block 2 Block 3

Cauliflower

Broccoli

FallowBroccoli

FallowCauliflower

August 2011

Block 1

Block 2 Bl k 3

Block 4Block 2 Block 3

MCUTC

ASD+MCUTC

November 2011ASD

ASD+MCUTC ASD

MC

Conventional site, Salinas, CA. 12 ms/g soil

Block 1 Block 2Block 3

Block 4

Cauliflower Broccoli

FallowAugust 2011

Block 1 Block 2Bl k 3Block 3

Block 4

May 2012ASD

Pic-Clor MC

ASD+MCUTC

Variables Monitored• N dynamics

• Soil nitrate (0-6” depth) • Soil nitrate (0-6 depth) • Verticillium dahliae

• Viable microsclerotia in soil (ms/g soil)Viable microsclerotia in soil (ms/g soil)• Wilt score: 1 (healthy) – 8 (dead)• Infection rate of strawberry plant (%)Infection rate of strawberry plant (%)

• Crop yield and biomass

Soil Nitrate Dynamics (Org. 0-15cm)

140

160UTCMCStrawberry

100

120

ry s

oil ASD

ASD+MCa

Broccoli/

y

6 th

80

100

mg/

kg d

r Broccoli/cauliflower

Lettuceaba

~6 months

40

60

NO

3-N

m

Cover cropbc

c

aab aa

ab

0

20 b b

aababb

0Jun-11 Oct-11 Feb-12 Jun-12 Oct-12 Feb-13 Jun-13

Soil Nitrate Dynamics (Conv. 0-15cm)

140

160UTCMC

Strawberrya

100

120

dry

soil

MCASDASD+MCPic Clor

Broccoli/cauliflower a

ab

aab

80

100

mg/

kg d Pic-Clor

bc

ab

40

60

NO

3-N

c

b

b

a

abb

20

c bab

ababb

0Jun-11 Oct-11 Feb-12 Jun-12 Oct-12

Salt Burn Damage at ASD plots (Conv. Jan. 2012)

ASD w/ 9t/ac rice bran (N 2%) -> total 360 lbs-N/acASD w/ 9t/ac rice bran (N 2%) total 360 lbs N/acMC 1.5t/ac (N 6%) -> total180 lbs-N/acASD w/ 7.5t/ac rice bran + MC 1.5t/ac -> total 480 lbs-N/ac…….plus inorganic N from pre-crop residues!

8.0UTC

Wilt Score of Strawberry Plants

6.0

7.0 UTC

MC

ASD*

y(Org. )

4 0

5.0

lt score ASD

ASD+MCaababb

3.0

4.0

Wil

1.0

2.0

M 12 J 12 J l 12 A 12 S 12 O t 12May‐12 Jun‐12 Jul‐12 Aug‐12 Sep‐12 Oct‐12

Main (P=0.35):  n.s.Sub (P 0 0057**): ASD ASD+MC MC UTC

Organic StrawberryV dahliae Infection Rate %

120

Sub (P=0.0057**):    ASD    ASD+MC   MC    UTC

Main x Sub (P=0.98):  n.s.Treatments on the same line are not significantly different (Tukey’s HSD test (P=0.05)).

V. dahliae Infection Rate %

80

100

tion rate %

( ))

60

ahlia

e infestat

40

Verticillium da

0

20V

UTC MC ASD ASD+MC UTC MC ASD ASD+MC UTC MC ASD ASD+MC

Fallow Cauliflower Broccoli

Changes in Verticillium dahliae Microsclerotia Number i T il f O i i

Treatment Sampling Date

Post- Post-

in Topsoil of Organic site.

Baseline Broccoli/Cauliflower Pre-ASD/MC Post-ASD/MC Strawberries June 2011 Sep. 2011 Sep. 2011 Oct. 2011 Sep. 2012

Main plot Fallow 0.6 0.0 1.5 0.5 0.0Cauliflower 0.4 0.4 2.1 0.0 0.0 Broccoli 0.5 0.3 1.0 0.1 0.0 ANOVA (P) 0.81 0.24 0.51 0.35 -

Sub plot pUTC 1.2 0.7 1.5 0.5 0.0 MC 0.0 0.2 1.7 0.3 0.0 ASD 0.5 0.0 1.3 0.0 0.0ASD+MC 0.3 0.0 1.7 0.0 0.0ANOVA (P) 0.06 0.08 0.99 0.15 -   Statistical analysis was performed for log-transformed data. Numbers in the table show

the back-transformed populations of viable V. dahliae microsclerotia/gram soil.

1200

Main (P=0.58): n.s.Sub (P=0.0001***):UTC  MC   ASD   ASD+MCOrg. Strawberry

M k t bl F it

1000

Main x Sub (P=0.10): n.s. Treatments on the same line are not significantly different (Tukey’s HSD test (P=0.05)).

Marketable Fruit Yield

800

ms/plant

400

600

uit yield gram

200

400

Fru

0

UTC MC

ASD

+MC

UTC MC

ASD

+MC

UTC MC

ASD

+MC

ASD

+

ASD

+

ASD

+

Fallow Cauliflower Broccoli

1000Org. Strawberry

800 UTC

MC

A

AB

g yMarketable Fruit Yield

600

gram

s/plant

MC

ASD

ASD+MC BC

C

400ble fruit yield g

N fertility effect V. wilt suppression effect

200

Marketab

200

0Mar‐12 Apr‐12 May‐12 Jun‐12 Jul‐12 Aug‐12 Sep‐12 Oct‐12

Main (P=0.6): n.s.Conv.S b

( )Sub (P=0.01*): UTC MC ASD ASD+MC Pic-Clor

Main x Sub (P=0.31): n.s.

StrawberryMarketable Fruit Yield(early to mid season yield)yield)

Org. Romaine LettuceMarketable Yield

10 V. dahliae microsclerotia number in top soil (Org. site. Post lettuce. Sep. 2013.

8

#/g soil

(Org. site. Post lettuce. Sep. 2013. 2 years after ASD treatment)

Main (P=0.37):  n.s.S b (P 0 02*) ASD ASD MC MC UTC

6

osclerotia  Sub (P=0.02*): ASD   ASD+MC   MC   UTC

Main x Sub (P=0.32): n.s.

4

liae micro

2

V. dah

l

0

UTC MC

ASD

SD+M

C

UTC MC

ASD

SD+M

C

UTC MC

ASD

SD+M

C

AS

AS

AS

Fallow CauliflowerCauliflowerCauliflowerCauliflowerBroccoliBroccoliBroccoliBroccoliFallow                            Cauliflower Broccoli

Summary

• N dynamics:• Rice bran provided significant amount of nitrate • Rice bran provided significant amount of nitrate

for ~6 months from ASD treatment• Benefitted early growth and yield• Benefitted early growth and yield• Excess N caused salt damage to strawberry

plants (esp Conv site)plants (esp. Conv. site)• Need to reduce N inputs in ASD by using lower-

N carbon source or lowering rate of rice branN carbon source or lowering rate of rice bran

Summary (Cont.)y ( )

• V. dahliae suppression:V. dahliae suppression:• ASD+MC and ASD showed reduction of

V. dahliae infection in strawberry plant (Org. site)V. dahliae infection in strawberry plant (Org. site)• V. dahliae microsclerotia number in soil was lower

at ASD and ASD+MC even after 2 years from at ASD and ASD MC even after 2 years from treatment

Summary (Cont.)y ( )

• Crop yield:• Strawberry’s marketable fruit yield at ASD and

ASD+MC was highest in Org. and ASD+MC was comparable to fumigation in Conv (early mid season comparable to fumigation in Conv. (early-mid season yield)

• Overall:Overall:• ASD reduced V. wilt and increased yield but no additive

or synergistic effect of MC and/or broccoli rotation was observed

• Yield increase in ASD appears to be caused by a bi ti f N i i ( l ) d di combination of N provision (early season) and disease

suppression (late season)

Exp. 2: Carbon source trial (PSI, Watsonville)• Rhizoctonia‐infested field• RB split plot. 4 repsMain plots:

• ASD RB 9 t/ac • ASD RB 6 t/acASD RB 6 t/ac• ASD ground dry grape pomace (GP) 9 t/ac

• Methyl bromide/chloropicrin • Methyl bromide/chloropicrin • UTC

Split plots:Bed top application!

• With and with pre‐plant fertilizer (PPF. 650 lb/ac of 6‐month slow‐release 18‐6‐12))

• In‐season fertilizer (all plots)March‐Aug. 45‐19‐51 lbs/ac Albion plants

Ground Dry Grape Pomace Rice Bran (grape skin + seeds)

N:2.1%, C:49%, C/N:23 N:2.3%, C:41%, C/N:18

Disease suppression effect

PPF effect

~5‐6 months

80 Soil Inorganic N in PSI‐ASD Trial [0"‐6" depth, w/o PPF](Pre‐ASD treatment, Oct. 1, 2013)

60

40N m

g/kg

40

Inorganic 

Average of NH4‐N mg/kg dry soil 

Average of NO3‐N mg/kg dry soil

20

B BAB B

0w/o PPF w/o PPF w/o PPF w/o PPF w/o PPF

UTC ASD GDGP ASD Rice Bran 6ton

ASD Rice Bran 9ton

MB/PIC

80 Soil Inorganic N in PSI‐ASD Trial [0"‐6" depth, w/o PPF](Post‐ASD treatment, Nov. 6, 2013)

60Average of NH4‐N mg/kg dry soil Average of NO3‐N mg/kg dry soil

40N m

g/kg

40

Inorganic 

A

A

20AB

B

0w/o PPF w/o PPF w/o PPF w/o PPF w/o PPF

C

UTC ASD GDGP ASD Rice Bran 6ton

ASD Rice Bran 9ton

MB/PIC

80 Soil Inorganic N in PSI‐ASD Trial [0"‐6" depth, w/o PPF](2 months after ASD, Jan. 10, 2014)

60

Average of NH4‐N mg/kg dry soil 

Average of NO3‐N mg/kg dry soil

40N m

g/kg

AAB

40

Inorganic 

20BC

CC

0w/o PPF w/o PPF w/o PPF w/o PPF w/o PPF

UTC ASD GDGP ASD Rice Bran 6ton

ASD Rice Bran 9ton

MB/PIC

Estimated Mineral N InputTreatment PPN PPN PPN In‐ Total MrktTreatment PPN 

totalN

lb /

PPN minrl.rate %

PPNminrl. Nest. lb /

In‐season 

Nlb /

Total minrl.est. Nlb /

Mrkt.Fruit yield

lb / (%)lbs/ac % lbs/ac lbs/ac lbs/ac lbs/ac (%)ASD GP9w/o PPF* 378 0 0 45 45 54,698 (76)w/o PPFASD GP9w/ PPF*

378 +117

0 +100

0 +117 45 162 69,024 (96)

ASD RB6w/o PPF* 276 50 138 45 183 70,435 (98)

ASD RB9ASD RB9w/o PPF* 414 50 207 45 252 69,871 (97)

MB/Pic 00 62 ( 00)MB/Picw/PPF* 117 100 117 45 162 71,741(100)

* PPF: Pre‐plant fertilizer. 650 lb/ac of 6‐month slow‐release 18‐6‐12

70

80N Mineralization Rate of

Defatted Rice Bran and Mustard Seed Meal (Incubation experiment)

60

70 [Andosol, 60% WFPS, 86 °F. Noguchi, 1992]

~60%

50

n rate (%

)

~50%

60%

30

40

eralization

20

30

Mine

Mustard seed mealRice bran (defatted)

10

00 1 2 3 4 5 6 7

Incubation period (weeks)

Estimated Mineral N InputTreatment PPN PPN PPN In‐ Total MrktTreatment PPN 

totalN

lb /

PPN minrl.rate %

PPNminrl. Nest. lb /

In‐season 

Nlb /

Total minrl.est. Nlb /

Mrkt.Fruit yield

lb / (%)lbs/ac % lbs/ac lbs/ac lbs/ac lbs/ac (%)ASD GP9w/o PPF* 378 0 0 45 45 54,698 (76)w/o PPFASD GP9w/ PPF*

378 +117

0 +100

0 +117 45 162 69,024 (96)

ASD RB6w/o PPF* 276 50 138 45 183 70,435 (98)

ASD RB9ASD RB9w/o PPF* 414 50 207 45 252 69,871 (97)

MB/Pic 00 62 ( 00)MB/Picw/PPF* 117 100 117 45 162 71,741(100)

* PPF: Pre‐plant fertilizer. 650 lb/ac of 6‐month slow‐release 18‐6‐12

190 kg/ha = 170 lbs/ac

(Bottoms et al., 2013)

Summary1 ASD ith i b 6 t/ k d ll ith t ifi i1. ASD with rice bran 6 t/ac worked well without sacrificing 

fruit yield and having excess soil inorganic N2 Ground dry grape pomace 9 t/ac worked but only with2. Ground dry grape pomace 9 t/ac worked but only with 

pre‐plant fertilizer3. Pre‐plant fertilizer was not necessary when rice bran 6 to p y

9 tons/ac was used4. All above have to be examined in flat rice bran 

li ti /i ti tapplication/incorporation systems5. NH4‐N dominates immediately after ASD, then gradually 

nitrifiednitrified6. ~40 mg/kg of soil inorganic N (0”‐6” depth) until April to 

May was sufficient to achieve the highest yieldy g y7. For N balance in fields using organic amendments, 

mineralization rates of materials have to be considered

ASD: On-going Studies/Challenges

Controlling emerging diseases caused by Fusarium oxysporum and Macrophomina phaseolinay p p pReducing N input from C-sources

Cover crop + Low rate of rice branRevisit molasses mixes

Evaluating environmental impactsGreenhouse gas emission, nitrate leaching, phosphorus accumulation

Ineffective in heavy soils?Ineffective in heavy soils?Large clods in beds prevent development of anaerobic condition

Understanding biological mechanismsChanges in functional diversity of soil microorganisms?

AcknowledgementsWe gratefully acknowledge funding for this work from the following:

USDA NIFA MBTP Award # 2012-51102-20294USDA WSARE Award # SW11-116Organic Farming Research Foundation

And the many growers, extension and industry people who have made this work possiblepeople who have made this work possibleGary Tanimura, Glenn Noma, Tanimura and Antle Fresh Foods Inc.Liz Mirazzo, Andy Webster of CASFS, UCSCLuis Rodriguez, Patti Wallace, Mike nelson, Plant Science inc.K K ij L M h P A l UCCEK. Kammeijer, L. Murphy, P. Ayala, UCCELab assistants, interns, and volunteers of the Shennan lab, UCSC

Questions?

joji@ucsc.edu