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Strawberry I Tuesday morning 9:00 am Where: Grand Gallery (main level) Room A & B MI Recertification credits: 2 (1C, COMM CORE, PRIV CORE) OH Recertification credits: 0.5 (presentations as marked) CCA Credits: SW(0.5) PM(0.5) CM(1.5) Moderator: Kevin Schooley, Ontario Berry Growers 9:00 am The Intricacies of Silicon Fertilization (OH: 2B, 0.5 hr) Richard Belanger, Laval Univ., Quebec 9:45 am Emerging Technologies: How Can These Help Strawberry Growers Pam Fisher, Ontario Ministry of Agriculture and Food Kevin Schooley, Ontario Berry Growers 10:15 am Getting the Most out of Your Irrigation System Jean Caron, Univ. of Laval, Quebec 11:00 am Home Grown Innovations - Show and Tell Scott Thompson, Thompson Strawberry Farm, Bristol, WI, Panel Moderator 12:00 noon Session Ends

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Strawberry I

Tuesday morning 9:00 am

Where: Grand Gallery (main level) Room A & B

MI Recertification credits: 2 (1C, COMM CORE, PRIV CORE)

OH Recertification credits: 0.5 (presentations as marked)

CCA Credits: SW(0.5) PM(0.5) CM(1.5)

Moderator: Kevin Schooley, Ontario Berry Growers

9:00 am The Intricacies of Silicon Fertilization (OH: 2B, 0.5 hr)

Richard Belanger, Laval Univ., Quebec

9:45 am Emerging Technologies: How Can These Help Strawberry Growers

Pam Fisher, Ontario Ministry of Agriculture and Food

Kevin Schooley, Ontario Berry Growers

10:15 am Getting the Most out of Your Irrigation System

Jean Caron, Univ. of Laval, Quebec

11:00 am Home Grown Innovations - Show and Tell

Scott Thompson, Thompson Strawberry Farm, Bristol, WI, Panel

Moderator

12:00 noon Session Ends

The intricacies of silicon fertilization Richard Bélanger Département de phytologie, Université Laval, Quebec, Quebec G1V 0A6, Canada [email protected] While being classified as non-essential for plant growth, silicon (Si) has long been recognized for its prophylactic properties against a wide array of biotic and abiotic stresses. However, practical use of Si has been hampered by conflicting reports about its mode of action, application, and mostly about how and what plants can benefit from Si. The recent discovery of Si transporters in rice, along with new developments in genomics and sequencing data now make it possible to investigate with precision what plant species possess the molecular tools to uptake Si from the soil. In this context, strawberry remains enigmatic because it is considered a poor accumulator of Si and yet is the subject of several reports linking Si fertilization with benefits. Over the last few months, we have investigated the presence and expression of Si transporters in strawberry, along with Si accumulation in different cultivars and the effect of Si fertilization against strawberry powdery mildew. As will be discussed in the presentation, combining molecular approaches with field applications should lead to optimal recommendations for strawberry growers interested in exploiting the beneficial properties of Si. References  

•   Vivancos, J., R. Deshmukh, C. Grégoire, W. Rémus-Borel, F. Belzile, & R.R. Bélanger. (2016). Identification and characterization of silicon efflux transporters in horsetail (Equisetum arvense). J. Plant Physiol. In press

 •   Deshmukh, R.K., J. Vivancos, G. Ramakrishnan, V. Guérin, G. Carpentier, H. Sonah, C.

Labbé, P. Isenring, F. J. Belzile, & R.R. Bélanger. (2015). A precise spacing between the NPA domains of aquaporins is essential for silicon permeability in plants. The Plant Journal. 83:489-500.

 •   Deshmukh, R. and R.R. Bélanger. (2015). The functional role of silicon in plant biology-

Molecular evolution of aquaporins and silicon influx in plants. Functional Ecology. Doi: 10.1111/1365-2435.12570.

 •   Vivancos, J., C. Labbé, J. G. Menzies & R.R. Bélanger. (2015). Silicon-mediated

resistance of Arabidopsis against powdery mildew involves mechanisms other than the salicylic acid (SA)-dependent defence pathway. Mol. Plant Pathol. 16:572-582.

 •   Guérin, V., Cogliati, E.E., Hartley, S.E., Belzile, F., Menzies, J.G., & Bélanger, R.R.

(2014). A zoospore inoculation method with Phytophthora sojae to assess the prophylactic role of silicon on soybean cultivars. Plant Dis. 98: 1632-1638.

•   Ma, J.F., Tamai, K., Yamaji, N., Mitani, N., Konishi, S., Katsuhara, M., Ishiguro, M.,

Murata, Y., and Yano, M. (2006). A silicon transporter in rice. Nature 440: 688-691.

•   Mitani-Ueno, N., Yamaji, N., Zhao, F.-J., and Ma, J.F. (2011). The aromatic/arginine

selectivity filter of NIP aquaporins plays a critical role in substrate selectivity for silicon,

boron, and arsenic. J. Exp. Bot. 62: 4391-4398.

•   Fauteux, F., Rémus-Borel, W., Menzies, J.G., and Bélanger, R.R. (2005). Silicon and

plant disease resistance against pathogenic fungi. FEMS Microbiol. Lett. 249: 1-6.

 

16/11/2016

1

Richard  Bélanger,  Université LAVAL

The  Intricacies  of  Silicon  Fertilization

December 6,  2016

2016  North American  Berry  ConferenceGrand  Rapids,  Michigan

Silicon

Si14 28.086

What is Si  in  nature?

• Silicon:  Pure  Si;  virtually absent  in  nature• Silica:  SiO2 :  quartz,  sand,  non  soluble• Silicate:  SiO2   mixed  with sodium,  calcium,  aluminium  and  potassium• Low solubility ranging from 0.1  to  0.6  mM in  soils• Silicic acid:  soluble  form of  Si  in  the  form Si0H4.Maximum  solubility is1.7  mM at  physiological pH  (5-­‐7).  Only form that a  plant  can absorb

Von  Sachs,  1860

Essential elements for plant growth

Macronutrients:

Micronutrients

N, P, K, S, Ca, Mg

Fe, Mn, Zn, B, Cu, Mo and Cl

« Si »  is not  among them…

XIXth Century…

E.g.  Graminaceae

Rice and  sugarcane accumulate large  quantities of  Si  in  the  form of  silica gel  

SiO2.nH2O

Savant  et  al. 1999

And  yet… Si  content  in  plant  tissues  may varybetween 0.1  to  10%

0 50 100 150 200 250 300 350

Disease  resistance

Abiotic  stress  tolerance

Yield  and  quality

Silicon  as  fertilizer  

Pub lished  repo rts

Silicon  in  agriculture  in  the  literature

Over  1000 papers  reporting  beneficial  effects…

16/11/2016

2

ü Consensus:  prophylactic  role

First  reports  in  Chinese  and  Japanese  literature  in  the  1920’s

First  comprehensive  report  in  USA  by  Wagner  in  1940

ü Beneficial in  many plant/pathogeninteractions

0 50 100 150 200 250 300 350

D isease  re s istance

Ab io tic  stre ss  to le rance

Y ie ld  and  qua lity

S ilicon  as  fe rtilize r  

Pub lished  repo rtsHow  does silicon protect

plants  againstdiseases/stress?

The  beneficial  effects  of  Si  appear  to  be  correlated  with  the  intrinsic  ability  of  a  plant  to  accumulate  Si      accumulate  

ü How  does silicon protectplants  againstdiseases/stress?

How  do  plants  absorb  Si?

ü The  beneficial  effects  of  Si  appear  to  be  correlated  with  the  intrinsic  ability  of  a  plant  to  accumulate  Si

ü How  does silicon protectplants  againstdiseases/stress?

ü The  beneficial  effects  of  Si  appear  to  be  correlated  with  the  intrinsic  ability  of  a  plant  to  accumulate  Si

ü How  do  plants  absorb  Si?

ü How  does silicon protectplants  againstdiseases/stress?

Water  flux

cortex

xylem

Silicic  acid Lsi1 Lsi2

Silicon  transport  in  plants

From  the  roots  to  the  leaves:  e.g.  WHEAT

Only the  soluble  formmonosilicicacidSi(OH)4can beabsorbed by  the  plant

16/11/2016

3

The  influx  transporter  Lsi1  is  the  essential  filter  for    Si  absorption  in  plants:

…plants absorb  or  not  Si  on  the  basis  of  presence  of  Lsi1  or  not

Plants  lacking  Lsi1  and  unable  to  absorb  Si  :  • Arabidopsis  • Canola  • Rocket• Gerbera

Plants  known  to  have  Lsi1  and  absorb  Si:  • Cucurbits• Rice• Sugarcane• Soybean• Others…

Silicon  transport  in  plants

Lsi1

E.g.

Lsi1  proteins  specifically  belong  to  the nodulin 26-­‐like  intrinsic  protein (NIPs)  a  sub-­‐family  of  aquaporins

Silicon  transport  in  plants

Lsi1

GB.C

extracellular

membrane

cytoplasmic

NPA  domain

helix

water water

1

2

3

4 5

6

C N

Can  we predict if  a  plant  can absorb Si  on  the  basis  of  the  presence of  NIP-­‐III  aquaporins?

Hypothesis

Identification  of  NIPs  in  25  plant  species  through  comparative  genomics  approach  and  phylogenetic  analysis

All  Known  Si  transporters  grouped  in  NIP-­‐III

16/11/2016

4

Maize

??

No  report  of  significant  Si  accumulation  in  any  of  the  species  belonging  to  the  Solanaceae

Can  we predict if  a  plant  can absorb Si  on  the  basis  of  the  presence of  NIP-­‐III  aquaporins?

Hypothesis

Inability  may  be  because  of

Structural  variation  in  protein  

Tomato  known  as  poor  accumulator  has  putative  Si  transporter  (SlNIP2-­‐1)!  

GB.C

Lsi1  structure  model

108  a.a.  between  the  two  NPA  loops

Structural  variation  in  protein?

Plant  species Gene  ID  (Froger ’s  residues,  NPA-­‐NPAdistance) Si  accumulator   (Reference)

Brachypodium  distachyon BdNIP2-­‐1  (LTAYF,  108),  BdNIP2-­‐2  (LTAYF,  108) Yes  (present  study)

Cajanus  cajan CcNIP2-­‐1  (FTAYF,  108),  CcNIP2-­‐1  (LTAYF,  108) Yes  (Hodson  et  al.,  2005)

Carica  papaya CpNIP2-­‐1  (LSAYF,  108) ?

Citrus  sinensis CsNIP2-­‐1  (LTAYL,  43) ?

Elaeis  guineensis EgNIP2-­‐1  (LTAYL,  108) Yes  (Gowda  et  al.,  2004)

Fragaria  vesca FvNIP2-­‐1  (LTAYM,  108),  FvNIP2-­‐5  (LTAYV,  108) Yes  (Kanto  et  al.,  2004)

Glycine  max GmNIP2-­‐1  (LTAYM,  108),  GmNIP2-­‐5  (LTAYV,  108) Yes  (present  study)

Musa  acuminate MaNIP2-­‐1  (LTAYF,  108),  MaNIP2-­‐2  (LTAYL,  108),  MaNIP2-­‐3  (LTAYF,  108),  MaNIP2-­‐4  (LTAYF,  108)

Yes  (Henriet  et  al.,  2006)

Oryza  sativa OsNIP2-­‐1  (ITAYF,  108),  OsNIP2-­‐2  (LTAYF,  108) Yes (Ma  et  al.,  2006)

Prunus  persica PpNIP2-­‐1  (LTAYV,  108) Yes  (LeBlond  et  al.,  2011)

Populus  trichocarpa PtNIP2-­‐1  (LTAYL,  108) Yes  (present  study)

Ricinus  communis RcNIP2-­‐1  (LTAYI,  108) ?

Sorghum  bicolor SbNIP2-­‐1  (LTAYF,  108),  SbNIP2-­‐2  (LTAYF,  108) Yes  (Lux  et  al.,  2002)

Setaria  italic SiNIP2-­‐1  (LTAYF,  108),  SiNIP2-­‐2  (LTAYF,  108) Yes  (Weichenthal  et  al.,  2003)

Solanum  lycopersicum SlNIP2-­‐1  (LSAYI,  109) No  (present  study)

Vitis  vinifera VvNIP2-­‐1  (LTAYA,  108) Yes  (Blaich  and  Grundhofer,  1997)

Zea  mays ZmNIP2-­‐1  (LTAYF,  108),  ZmNIP2-­‐2  (LTAYF,  108),  ZmNIP2-­‐3  (LTAYF,  108),  ZmNIP2-­‐4  (LTAYF,  108)

Yes  (Morales  et  al.,  2005)

Citrus  sinensis CsNIP2-­‐1  (LTAYL,  43) ?

Solanum  lycopersicum SlNIP2-­‐1  (LSAYI,  109) No  (present  study)

Structural  variation  in  protein?

Does spacing between NPA  domains regulate Si  permeability?

Hypothesis

Functional  evaluation  of  NIP2-­‐1  genes  with  different  NPA  spacing  was  done  by  heterologous  expression

16/11/2016

5

Functional  evaluation  of  genes  with  different  NPA  spacings

o Species  confirmed  for  Si  uptake  ability

o Candidate  genes  cloned  from  poplar  and  tomato:  mutation  and  heterologous  expression  in  Xenopus oocytes

Results

108

108

109 43

Functional  evaluation  of  genes  with  different  NPA  spacings

o Species  confirmed  for  Si  uptake  ability

o Candidate  genes  cloned  from  poplar  and  tomato:  mutation  and  heterologous  expression  in  Xenopus oocytes

Effect  of  NPA  spacing  changes  in  poplar

Spacing  between  NPA  domains  was  changed  from  108  to  107  and  109  either  by  adding  or  removing  1  a.a.  in  PtNIP2-­‐1  of  poplar Loss  of  function

Sl_wildtypeSl_mutant

Sl_wildtypeSl_mutant

Sl_wildtypeSl_mutant

N C

TM1 TM2 TM3 TM4 TM5 TM6LA                                                          LB                                                        LC                                                    LD                                                      LE

G                                                                                                                                                                                        S          G            R

NPA

NPAVal

Attempt  to  create  functional  protein  in  tomato

Si  uptake  in  oocytes

Effect  of  NPA  spacing  changes  in  tomato

Gain  of  function

16/11/2016

6

In  summary

Only  and  all  plants  possessing  a  NIPIIIaquaporin  with  a  GSGR pore  and  a  NPA-­‐NPA  distance  of  108 amino  acids  can  absorb  Si  in  the  form  of  silicic  acid

In  summary

ü Only  and  all  plants  possessing  a  NIPIII aquaporin  with  a  GSGR pore  and  a  NPA-­‐NPA  distance  of  108 amino  acids  can  absorb  Si  in  the  form  of  silicic  acid It  is now possible  to  easily predict what

plants  can absorb Si  with molecular tools

What about  strawberry?

Pictures of  strawberry

Literature

Literature

o Ma  (2004):  Strawberry  is  a  non  accumulator  of  Silicon

Literature

o Kanto  et  al.  (2006):  0,5%  more  under  Si  treatment

o Miyake  and  Takahashi  (1986):  1,22%  Si

o Liang  et  al.  (2006):  Strawberry  uptakes  Si  passively

16/11/2016

7

Full  aquaporin  analysis  in  

Fragaria vescaSr. No

Manually assigned features based on protein sequence alignment

NPA-­‐NPA  Distance

NPA (LB) NPA (LE)Ar/R filters

H2 H5 LE1 LE2 TM

FvNIP1-1 NPA NPA W V A R 6 109FvNIP1-2 NPA NPA W V A R 6 126FvNIP1-3 NPA NPA W A A R 6 110FvNIP1-4 NPA NPA W V A R 6 109FvNIP1-5 NPA NPA W V A R 6 109FvNIP2-1 --- NPA G S G R 3FvNIP2-2 NPA NPA G S G R 6 109FvNIP2-3 NPA --- G S - - 3

FvNIP2-4 NPA NPA G S G R 6 108FvNIP2-5 NPA NPA G S G R 6 108FvNIP3-1 NPA NPA A V G R 6 108FvNIP3-2 NPA NPV T I A R 6 108FvNIP3-3 NPS NPV A I G R 6 108FvNIP5-1 NPS NPA S I A R 6 108

Genomic search for  Lsi1  candidate  proteins

FvNIP2-4 NPA NPA G S G R 6 108FvNIP2-5 NPA NPA G S G R 6 108

>FAN_iscf00233045.1.g00001.1_(+1)GGLIVTVMIYAVGHISGAHMNPAVTIAFATFRHFPWKQIGELAGIAVGSAVCITSIFAGPISGGSMNPARTIGPALASAYYNGVWIYMVGPVIGALLGAWSYSFIRVNDKPVQASSPRSLSLQLRRIKSDVNVQAVSICKDPLDFA*

>FAN_iscf00346118.1.g00002.1_(+1)MARTELVSVENPIVEHPFYPPGFLKKVVAEIIATFLLVFVTCGSSALSASDERKVSKLGASMTGGLIVTVMIYAVGHISGAHMNPAVTIAFATFRHFPWKMSKSSESNSDGRVHVCPRDVPDCVDHHRHYKPSGGSMNPARTIGPALASAYYNGIWIYMVGPVIGALLGAWSYSFIRVNDKPVQASPPRSLSLQLRRIKSDVNVQAVSICKDPLDFA*

Homologous  genes  found  in  

Fragaria ananassa ALIGNMENT

In  theory ,  strawberry has  the  proper genetic tools to  absorbsilicic acid from the  soil…

The  role  of  silicon  in  the  suppression  of  strawberry  powdery  mildew

16/11/2016

8

Experimental  designSeascapeCharlotteMontereyAlbionAmandineVerity

Ø Day  neutral  cultivars

Ø Silicon  amendment:   Liquid  potassium  silicate  (Kasil©)  at  a  concentration  of  1.7  mM

Analyses:

Yield  and  fruit  quality

Silicon  content

Powdery  mildew  incidence

Natural  powdery  mildew  infectionØ Disease:  Silicon  content  analysis

Powdery  mildew  incidence Yield  and  fruit  quality

In  conclusion

Strawberry has  the  proper genetic tools (aquaporins)  to  absorb Si

During the  course  of  a  season,  strawberry plants  can absorb as  much as  3%  Si

Silicon feeding had an  excellent  prophylactic role againstpowdery mildew on  strawberry,  which led to  a  better yield

Constant  supply of  Si  in  the  form of  silicic acid is preferable to  maximize absorption

2016‐11‐22

1

Getting the Most out of Your Irrigation System in Strawberry

Jean Caron, Lelia Anderson, Guillaume Sauvageau and Laurence GendronUniversité Laval, Département des Sols et de Génie AgroalimentaireCorresponding author: [email protected]

Great Lakes Fruit, Vegetable & Farm Market EXPO Michigan Greenhouse Growers EXPO December 6 ‐ 8, 2016 

DeVos Place Convention Center, Grand Rapids, MI

Introduction

86% of the strawberry of North America grown in California, along with Florida (7%) and Québec (3.5%)  and Ontario (3.5%)

Water is becoming increasingly scarce in California, and under increasing controlled use elsewhere. 

Introduction

Cuts may be imposed to strawberry growers to save water, with 

limited information on the impact on crop yield.

This also increases pressure to get more crop per drop 

A new approach was recently proposed to manage irrigation and 

offers the opportunity to maximize yield and generate water savings 

without affecting yield, getting the most of your irrigation system

Daily or Weekly estimates of past eventsto estimate water use (ET)Newer

Real time water use(flux –tension based)

Two commonly used approaches to run irrigation: water flux from soil to the plant  or estimated uptake from

weather conditions or from change in soil weight 

Evapotranspiration (ETo):Evapotranspiration (ETo):

• ETo is the loss of water by evaporation (from soil and plant surfaces) and transpiration (from plant tissues)

• Estimates of Et for a specific crop and area are used for irrigation scheduling:

Crop Et = ETo x Kc

Daily or Weekly estimates of past eventsto estimate water use (ET)Newer

Real time water use(flux –tension based)

Two commonly used approaches to run irrigation: water flux from soil to the plant  or estimated uptake from

weather conditions or from change in soil weight 

2016‐11‐22

2

Complementing ET in managing irrigation• ET: For a runner, adjusting your diet based on your weekly weight basis 

or your past calorie consumption: risk of reducing your efforts due to underfeeding if rate of feeding does not feed enough

• Tension real time: heart and calorie monitor: you will adjust your food uptake based on your real time consumption and your feeding rate hence optimizing your efforts. Irrigation initiated at a tension threshold hc to provide adequate soil water flux to the plant. It considers actual ET (s0 +q0) to make sure the plant is properly supplied during peak activity (in real time)  

hc

Part 1: Comparing grower managed (Crop ET and visual assessment) with a real time 

tensiometer approach

Using tension or suction forces to drive irrigation decisions

Using tension or suction forces to drive irrigation decisions

Stopping irrigation: tension drops

Initiating irrigation: threshold reached

Observed tension fluctuations at two depths under manual assessment

Saving water

Stay within the blue: initiate irrigation 

before being out of the blue zone with the 

top tensiometer: likely avoid prewetting and 

risk of slaking

Stop it before the lower tensiometer hits 

low values: avoid water logging and 

leaching

Newer approach to maintain the crop in a non limiting flux situation  (below hc) with two  tensiometers

Slow run track

Fast run track

hc

2016‐11‐22

3

Irrigation treatments applied though the growth cycle

(CRBD with 5 replicates)

Comparing irrigation threshold to initiate irrigation (top of the blue band)

Determine hc to get top yield irrespective of water use (2011-2014)

Establishment                  small roots & low ETC deep rooting & large canopy

‐35 kPa

Parameters Measured

Yield in sub‐sampling sites 

Size of the fruits (caliber)

Fruit quality using Brix index

Plant size (canopy area) 

Leaf Water Potential (SWP) using 

pressure chamber

Leaf temperature with infrared thermometer

Plant performance and hydric stress measurements (Weekly measurements from January to June)

Plant performance and hydric stress measurements (Weekly measurements from January to June)

Parameters Measured

Soil sampling and soil analysis (3 soil samples/plot)Initial properties

Texture Saturated Hydraulic Conductivity (Ksat) Soil Water Retention Curves Salinity (Electrical Conductivity (EC)) and pH

Weekly determination Soil salinity from SSE method (1: 1 suspension) Soil salinity (EC) using suction lysimeter Amount of water/ha using flowmeters (non replicated though)

Initial properties

Texture Saturated Hydraulic Conductivity (Ksat) Soil Water Retention Curves Salinity (Electrical Conductivity (EC)) and pH

Weekly determination Soil salinity from SSE method (1: 1 suspension) Soil salinity (EC) using suction lysimeter Amount of water/ha using flowmeters (non replicated though)

Results for 2012 to 2015 in California and Québec

Plant performance and water used(Weekly measurements from January to June)

15 minute real time soil water potential at 15 cm and 30 cm(3 reps) using wireless Hortau tensiometers

Irrigation initiated by the irrigator (2012,13, 14) or automated (2015)

Plant performance and water used(Weekly measurements from January to June)

15 minute real time soil water potential at 15 cm and 30 cm(3 reps) using wireless Hortau tensiometers

Irrigation initiated by the irrigator (2012,13, 14) or automated (2015)

Watsonville Salinas Oxnard

Soil seriesClear Lake clay

Salinas Clay and

Mocho silty loam

Hueneme sandy

loamYield difference

from optimum thresholds

16% (8,000 pounds

per acre)17% 14%

Optimum tension

cbars (top of blueband)

10 13 8

Acre foot/Acre

difference betweentreatments

0.30 0.15 0.15

Percentage of crop

ET for top yield 75 49 114

Effects of real time irrigation management on strawberry production:

Real-time irrigation: summarizingReal-time irrigation: summarizingReal time management:

Irrigation triggered

Irrigation stopped before leachingFast leaching = 0 kPa

Etc management:

Irrigation triggered too late

Too long irrigation = leachingand waterlogging

2016‐11‐22

4

Yield IncreaseRelative to Grower

Year Soil Type Region Grower  ‐10 kPa (%)

2011 Clay CA 100 93 0

Wastonville 2013 Clay CA 144 84 0

2014 Clay CA 83 83 26

2012 Silty Clay Loam CA 163 68 17

2012 Silty Clay Loam CA 100 114 14

2013 Sandy Loam CA 93 128 6

2014 Sandy Loam CA 100 154 7

2012 Gravelly Clay Loam QC 35 42 20

2013 Gravelly Clay Loam QC 49 42 18

2014 Gravelly Clay Loam QC 52 63 0

112 103 10CA: California; QC: Québec

Water Used% of crop ET

Average Water Use in Percentage of Crop ET (CA only):

Salinas

Oxnard

Île d'Orléans

Flux is important to be maintained non limiting through irrigation

Analyse statistique

Fig. 2. Predicted total fresh market yield (1 kgha-1 = 0.89 lbac-1) from average soil matric potential reached before irrigations using data from seven experimental sites (centered regression line).

Soil Matric Potential (kPa)

Fre

sh M

arke

t Yie

ld (

kgha

-1)

R2adj = 0.86

Analyse statistique

Fig. 3. Frequency distribution of average soil matric potentials reached before irrigations considering eight treatments under conventional irrigation management. Treatments consisted of the grower standard procedure, which aimed at applying 100% of crop ET, and of the treatment based on 100% of crop ET.

0

1

2

3

0-10 11-20 21-30 31-40 41-50

Fre

quen

cy D

istr

ibut

ion

of

Soi

l Mat

ric

Pot

enti

als

Intervals of Soil Matric Potential (-kPa)

Field Number

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

App

lied

Wat

er (

% o

f cro

p E

T )

0

20

40

60

80

100

120

140

160

Average = 94% Crop ET

Field Number

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Ap

plie

d W

ate

r (%

Cro

p E

T)

0

50

100

150

200

250

January - October

Avg = 146%

Percentage of crop ET applied by growers in 2010 and 2011 in the Watsonville area (drawn from Cahn, 2012)

2010 2011

LOSSES GAINSREDUCED INCOMES INCREASED INCOMES

Yield Gain lbac -1 lb supp. $lb -1 ($)1 290 64 500 1.00 64 500

INCREASED COSTS REDUCED COSTSIncreased Variable Costs Reduced Variable Costs

$lb -1 ($) acftac -1 Tot. Water $acft -1 ($)Operating Costs 0.50 32 250 Water Savings 0.20 10 150 1 500

Increased Fixed Costs Reduced Fixed CostsWireless Tensiometer Technology ($) ᴑ Depreciation (0% intesrest) 4 896 24 480 $ / 5 years ᴑ Annual Service Fees 3 000 ᴑ Initial Costs (Shipping & Installation) 195 975 $ / 5 years

($) ($)Total 40 341 Total 66 000

Payback Period: 0.8 year

ø

Net Change in Profit : 25 659 $

ø

Cost-benefit Analysis –Case study of a 50-acre farm

Assumption: conventional management triggers irrigation at -15 kPa, on average. We are looking at the gains and losses associated with the management based on tension at -10 kPa compared to conventional management at -15 kPa, for a 50 acre-farm.

Part 2: Using a real time tensiometer approach to manage deficit irrigation

2016‐11‐22

5

hc is expected to vary during the season because rooting depth (L) and crop ET 

(So) vary

Software and controllers could allow adjustment for increasing root and 

increasing ET and implement them for managing irrigation

Alternatively, a simpler approach could maintain a lower (‐35 kPa) threshold

when the roots and the plants are small and move to a higher (‐10 kPa 

threshold) when the plants gets bigger to save water  

Adjusting critical irrigation threshold

0

5

10

15

20

25

30

35

40

Jan‐14 Feb‐14 Mar‐14 Apr‐14 May‐14

hc(‐kPa)

Daily critical threshold (hc) calculated with Forecast of ET and with actual threshold using monitoring data of ET (Oxnard 2014)

hc Forecast

hc Real

Constant hc

0

5

10

15

20

25

30

35

1‐Jan 21‐Jan 10‐Feb 2‐Mar 22‐Mar 11‐Apr 1‐May 21‐May 10‐Jun 30‐Jun

hc (‐kPa)

Daily critical threshold (hc) calculated with Forecast of ET and with actual threshold using monitoring data of ET (Oxnard 2015)

hc forcasted

hc real

Constant hc

Irrigation treatments applied though the growth cycle

(CRBD with 5 replicates)

Main objective

Determine if adjusting the irrigation threshold hc could increase water productivity without

affecting yield

Establishment                  small roots & low ETC deep rooting & large canopy

1.37

1.51

1.78

1.94

2.12

1.38

0.00

0.50

1.00

1.50

2.00

2.50

2014

Control (Grower) Dry (‐35 kPa)

Variable (*) Roots (**)

Wet (‐10 kPa) Etc

1.44

1.08

1.36

1.03

1.191.08

0.00

0.50

1.00

1.50

2.00

2.50

2015

Control (Grower) Dry (‐35 kPa)

Wet (‐10 kPa) Roots (**)

Variable (*) ETc

Cumulative total water use for the 2 seasons of experiment in ac‐ft/aca) Year 2015: from January 9th to June 11th 2015b) Year 2014: from November 26th 2013 to June 12th 2014 

Weighted Yields for 2014a) Weighted Total Yield  during the whole season  from January  02th to June 05th 2014 (lbs/ac);b) Weighted Marketable Yield (Fresh Market) from January 02th to April 18nd 2014 (lbs/ac);c) Relative Marketable Yield (Wet = 100% ) from January 02th to April 18nd 2014.

57287 59633

61195

61141

60783

30000

35000

40000

45000

50000

55000

60000

65000

Cumulative

 yield (lbs/ac)

Total Yield 

92

91

96

94

100

80

82

84

86

88

90

92

94

96

98

100

Cumulative

 yield (% of ‐10 kPa)

Relative MarketableYield

36728

36127

37948

37355 39718

30000

35000

40000

45000

50000

55000

60000

65000

Marketable Yield (fresh)

2016‐11‐22

6

54611

54258

56121

56225

57589

31000

36000

41000

46000

51000

56000

61000

Weigther 2015 Yields in lbs/ac

Total Yield (fresh + freezer)

34721

32923

34280

36123

36560

31000

36000

41000

46000

51000

56000

61000

Marketable Yield (fresh)

0.95

0.90

0.94

0.99

1.00

0.8

0.9

0.9

0.9

0.9

0.9

1.0

1.0

1.0

1.0

Relative Yield (Wet = 1.00)

Relative Marketable Yield (fresh)

Weighted Yields for 2015a) Weighted Total Yield (Fresh Market = Freezer) during the whole season (January 9th to June 11th 2015);b) Weighted Marketable Yield (Fresh Market) from January 9th to April 2nd 2015;c) Relative Marketable Yield (Wet = 1.00) from January 9th to April 2nd .

Summary of the performances for both years

Irrigation treatments Relative yield1 Water used

% acre‐foot per acre

Grower 91 1.41

‐10 kPa 100 1.74

‐35 kPa 93 1.30

Partial deficit

Roots 94 1.51

Variable 98 1.49

Reference ET ‐ 1.23

1Main effects significant at p=0.05

Treatments

Water use efficiency and relative yield

Statistical analyses were performed using proc mixed and proc GLM in SAS (p<0,05).

Step Wet 50% ET 100% ET Grower

Yield (% of 100% ET) 95 ab 105 a 76 c 100 a 83 bc

Water use efficiency (kg/ha.cm) 1539 a 1407 a 1531 a 1109 b 1208 b

Clay loam

Sandy loam

Statistical analyses were performed using proc mixed and proc GLM in SAS (p<0,05).

Step Dry Variable Wet Grower

Yield (% of Grower) 104 a 105 a 110 a 111 a 100 a

Water use efficiency (kg/ha.cm) 1229 a 1187 a 1118 a 996 b 846 c

Analyse statistique

Fig. 1. Effect of (1) average soil matric potential reached before irrigations and (2) irrigation management method on predicted total WU (1 acft.ac-1 = 3047 m3ha-1) using data from eight experimental sites (centered regression line).

Soil Matric Potential (kPa)

° Conventional Management + Ѱ-based Management

Wat

er U

se (

m3 h

a-1)

R2adj = 0.91

2016‐11‐22

7

0.12 0.28 0.41 0.81 4.05150 350 500 1000 5000

Deficit ѱ-based management

-kPa lbac -1 % acftac -1 %

-15 -1290 -4 -0.13 -7 (625) (598) (578) (511) 25-20 -2580 -7 -0.27 -11 (1 250) (1 196) (1 156) (1 022) 50-30 -5150 -16 -0.54 -23 (2 495) (2 387) (2 307) (2 039) 105

Yield decrease (relative to -10 kPa)

Water savings (relative to -10 kPa)

Net Gain (Loss)

($ac-1)

Operation Costs ($kg-1) ($lb -1 )

1.10 (0.50)

Annual Fresh Strawberry Price ($kg-1) ($lb -1 )

2.20 (1.00)

Water Price ($m-3) ($acpi -1 )

Deficit Irrigation –using wireless tensiometers

Impact on profit of a deficit irrigation (-15, -20, -30 kPa) relative to a wet management based on tension (-10 kPa)

Conclusions

• Real time management at ‐10 kPa is important for more crop per drop and higher revenues

• Target is ‐10 kpa to initiate irrigation, any stress even early in the season has generated yield decreases and revenue losses. 

• Water savings do not compensate for yield losses but at  a cost of 1000‐5000$ per acre‐foot

Ito bros Inc

Colleagues, students, research assistants: Carole Boily, Amélie Picard, Julien Cormier, Valérie Bernier, Guillaume Létourneau, Benjamin Parys, Laurence Gendron.

Hortau and technical support :Sébastien Rochette,  Jocelyn Boudreau, Shirley McClish, Derek Gagne, Omar Flores,TravisWilson, Philippe Sylvestre.

Growers and their teams : Henri Ito, Emily Paddock, Allison VandenHout, Lina, Agustin, Ruben, Lalo, Pascual Bruno.

University of California cooperative Extension : Oleg Daugovish and Michael Cahn