International conference “Aquaponics research mattes”Ljubljana, 22-24 March 2016

Nozzi Valentina, Graber Andreas, Mathis Alex, Schmautz Zala, Junge Ranka

Introduction

Zurich University of Applied Sciences / Life Sciences and Facility Management (Zurich, CH)

Some nutrients from the aquaculture effluents are present in insufficient quantities

for plants development

In some cases nutrients ought be supplemented to the aquaponic system to ensure

optimal performance of the plants

However, the addition of fertilizers increases the managerial and economic effort

Investigate the role of nutrients in order to optimize cost and management in

the aquaponics production

Material & method

AQUAPONICS

HYDROPONICS

• Fish tank

• Drum filter

• Biofilter

• solids thickening unit

• Hydroponic unit (3

tables, 1.2 m x 2 m each)

• Total water volume of

each system: 4,400 L.

• Hydroponic unit (3 tables,

1.2 m x 2 m each)

• Two sump (630L)

Aquaponics (3 systems):

Hydroponics (1 reference):

Sump

Hydroponic unit

Material & method

72 mushroom herbs

(Rungia klossii)

50 Nile tilapia (Oreochromis niloticus)

36 Lettuces(Lactuca sativa YACHT

variety (Salanova®))

72 mints(Mentha piperita

CHOCOLATE variety)

Material & method

Nutrients derived solely

from FISH FEED, no

supplementation

• Fish feed

• Micronutrient (Zn, B,

Mg, Mo, Cu, Fe)

• Iron

• Fish feed

• Micronutrient (Zn, B,

Mg, Mo, Cu, Fe)

• Iron

• Macronutrients (P, K)

HYDROPONIC SOLUTION:

• Micronutrient (Zn, B,

Mg, Mo, Cu, Fe)

• Iron

• Macronutrient (P, K)

• Nitrogen (NO3, NH4)

• Ca

A B C DAquaponic HydroponicAquaponicAquaponic

Nutrients, cost and management effort

-

Material & method

The experimentation ended when plants reached the

commercial size, 4 weeks after the beginning

Material & method

Final biomass

Specific growth rate

feed conversion ratios

Total Biomass

Fresh shoot weight

Fresh root weight

Root/shoot ratio

Chlorophyll content (Chl)

Epidermal UV-absorbance (Flv)

Flavonols (Flv)

Nitrate content

Organic Matter

CHN- elemental analysis

NO3-N

TN

PO4-P

K

Fe

Ca

Mg

°dH

t°

pH

EC

O2

Results

NO3-N

8 11 14 17 20 23 26

40

60

80

100

120A

B

C

D

days

mg

/L

TN

14 17 20 23 2640

60

80

100

120A

B

C

D

daysm

g/L

PO4-P

8 11 14 17 20 23 260

10

20

30

40A

B

C

D

days

mg

/L

K

8 11 14 17 20 23 260

50

100

150

200A

B

C

D

days

mg

/L

Fe

8 11 14 17 20 23 260

1

2

3

4A

B

C

D

days

mg

/L

Mg

8 11 14 17 20 23 260

10

20

30

40

50

60A

B

C

D

days

mg

/L

Ca

8 11 14 17 20 23 26

50

75

100

125

150A

B

C

D

days

mg

/L

°dH

8 11 14 17 20 23 260

10

20

30

40A

B

C

D

days

mg

/L

NO3-N

8 11 14 17 20 23 26

40

60

80

100

120A

B

C

D

days

mg

/L

TN

14 17 20 23 2640

60

80

100

120A

B

C

D

days

mg

/L

PO4-P

8 11 14 17 20 23 260

10

20

30

40A

B

C

D

days

mg

/L

K

8 11 14 17 20 23 260

50

100

150

200A

B

C

D

days

mg

/L

Fe

8 11 14 17 20 23 260

1

2

3

4A

B

C

D

days

mg

/L

Mg

8 11 14 17 20 23 260

10

20

30

40

50

60A

B

C

D

days

mg

/L

Ca

8 11 14 17 20 23 26

50

75

100

125

150A

B

C

D

days

mg

/L

°dH

8 11 14 17 20 23 260

10

20

30

40A

B

C

D

days

mg

/L

Date / Duration Parameters Tank A Tank B Tank C

04.05.2015

Number of fish 50 50 50

Total weight (kg) 12.4 10.8 11.3

Average weight per fish (kg) 0.25 0.22 0.23

30.06.2015

Number 49 50 50

Total weight (kg) 24.1 21.0 24.2

Average weight per fish (kg) 0.49 0.42 0.48

57 days

Specific growth rate (%/d) 1.20 1.17 1.33

Feed conversion ratio (kgfeed/kgfish biomass) 1.25 1.49 1.16

Results

Lactuca sativa Mentha piperita Rungia klossii

A B C D A B C D A B C D

Total n. of plants 36 36 36 36 72 72 72 72 72 72 72 72

n. of no-saleable plants 1 / / / 6 / / / / / / /

n. of plants harvested 35 36 36 36 66 72 72 72 72 72 72 72

Total biomass (fresh) kg 9.2 10.6 13.5 12.4 7.7 11.6 10.5 9.9 1.31 1.25 0.76 0.98

Shoot (fresh) kg 8.0 9.8 12.3 11.3 5.7 9.5 9.0 8.7 0.67 0.66 0.43 0.53

Roots (fresh) kg 1.2 0.8 1.2 1.1 2.0 2.1 1.6 1.2 0.64 0.58 0.33 0.44

Average shoot weight g 222 272 341 314 79 132 124 120 9.3 9.2 6.0 7.4

Production (shoot) kg/m2 4.0 4.9 6.1 5.7 3.1 4.8 4.5 4.3 0.34 0.33 0.21 0.27

Results

Results

ROOT/SHOOT RATIO

L. sativa

A B C D0

1000

2000

3000

4000

mg

/kg

M. piperita

A B C D0

1000

2000

3000

4000

mg

/kg

R. klosii

A B C D0

1000

2000

3000

4000ab

a

abb

mg

/kg

L. sativa

A B C D0

1000

2000

3000

4000

mg

/kg

M. piperita

A B C D0

1000

2000

3000

4000

mg

/kg

R. klosii

A B C D0

1000

2000

3000

4000ab

a

abb

mg

/kg

L. sativa

A B C D0

1000

2000

3000

4000

mg

/kg

M. piperita

A B C D0

1000

2000

3000

4000

mg

/kg

R. klosii

A B C D0

1000

2000

3000

4000ab

a

abb

mg

/kg

L. sativa

A B C D0

1000

2000

3000

4000

mg

/kg

M. piperita

A B C D0

1000

2000

3000

4000

mg

/kg

R. klosii

A B C D0

1000

2000

3000

4000ab

a

abb

mg

/kg

L. sativa

A B C D0

1000

2000

3000

4000

mg

/kg

M. piperita

A B C D0

1000

2000

3000

4000

mg

/kg

R. klosii

A B C D0

1000

2000

3000

4000ab

a

abb

mg

/kg

NITRATE IN LEAVES

L. sativa

A B C D0.00

0.05

0.10

0.15

0.20

0.25

A

a

b

b b

roo

t:sh

oo

t ra

tio

M. piperita

A B C D0.0

0.1

0.2

0.3

0.4

0.5

B

a

b bb

roo

t:sh

oo

t ra

tio

R. klosii

A B C D0.0

0.2

0.4

0.6

0.8

1.0

C

a

b

c bc

roo

t:sh

oo

t ra

tio

L. sativa

A B C D0.00

0.05

0.10

0.15

0.20

0.25

A

a

b

b b

roo

t:sh

oo

t ra

tio

M. piperita

A B C D0.0

0.1

0.2

0.3

0.4

0.5

B

a

b bb

roo

t:sh

oo

t ra

tio

R. klosii

A B C D0.0

0.2

0.4

0.6

0.8

1.0

C

a

b

c bc

roo

t:sh

oo

t ra

tio

L. sativa

A B C D0.00

0.05

0.10

0.15

0.20

0.25

A

a

b

b b

roo

t:sh

oo

t ra

tio

M. piperita

A B C D0.0

0.1

0.2

0.3

0.4

0.5

B

a

b bb

roo

t:sh

oo

t ra

tio

R. klosii

A B C D0.0

0.2

0.4

0.6

0.8

1.0

C

a

b

c bc

roo

t:sh

oo

t ra

tio

In lettuce, nitrate content was

below the threshold value

(3000 mg/Kg)

Mints and mushroom plant are

not subjected to nitrate

legislation

Higher in system A respect

to others groups in the three

plant species

Significantly higher in

system B respect to C, in

mushroom herb.

Results

CHL - L. sativa

A B C D0

10

20

30

b b

a

ab

FLAV - L. sativa

A B C D0.0

0.1

0.2

0.3

0.4

0.5

NBI - L. sativa

A B C D0

20

40

60

80

CHL - M. piperita

A B C D0

10

20

30

40

FLAV - M. piperita

A B C D0.0

0.5

1.0

1.5

2.0

a

b b b

NBI - M. piperita

A B C D0

10

20

30

40

50

a

b

ab

b

CHLOROPHYLL AND FLAVONOLS

(only in lettuce and mint)

Salads: Chlorophyll levels were highest in

System A in respect to Systems C and D

Mints: Flavonol levels were significantly

higher in System A than in systems B, C and

D.

Results

L. sativa -shoot

A B C D0

1

2

3

4

5

dry

we

igh

t %

M. piperita-shoot

A B C D0

5

10

15

dry

we

igh

t %

R. klosii-shoot

A B C D0

5

10

15

dry

we

igh

t %

L. sativa-roots

A B C D0

1

2

3

4

5

dry

we

igh

t %

M. piperita-roots

A B C D0

2

4

6

dry

we

igh

t %

R. klosii-roots

A B C D0

2

4

6

8

dry

we

igh

t %

DRY MATTER CONTENT

Lettuce and mint: higher dry

matter content in system A

both in shoots and roots.

Mushroom herbs shoots:

higher dry matter content in

system A

Mushroom herbs roots:

highest dry matter content in

system C

Results

L. sativa

-shoot-

A B C D0

5

10

15

a

ab b b

A

C/N

M. piperita

-shoot-

A B C D0

5

10

15

a

b b b

B

C/N

R. klosii

-shoot-

A B C D0

2

4

6

8

10

aab

bb

C

C/N

L. sativa

-roots-

A B C D0

5

10

15

a

bab

c

C/N

M. piperita

-roots-

A B C D0

5

10

15

a

ab b b

C/N

R. klosii

-roots-

A B C D0

2

4

6

8

ab aab b

C/N

CARBON TO NITROGEN RATIO

In the non-fertilized system A

the C/N content of the

biomass was higher as in

systems B, C and D.

Exception: mushroom herb

Discussion

THE SHORTAGE OF MICRONUTRIENT INDUCED MODIFICATION IN LETTUCE GROWTH IN NON-FERTILIZED SYSTEM A

allocate energy to

increase roots

In non-fertilized

System A

P and Fe shortage

Slow shoots growth

nitrogen intake

C/N ratio

(modification in

macromolecules

allocation)

Dry Matter

content

nitrate content in the shoots

carbohydrate production

root/shoot ratio

Lettuce, cultivated a medium with micronutrient shortage, had lowest growth. However, this was

associated with a lower content of nitrates; which implies a better nutritional quality of lettuce.

INVOLVE IN OSMOTIC ADJUSTMENT

WITH A INVERSELY PROPORTIONAL

RELATIONSHIP

PLANTS RESPONDED TO DIFFERENT NUTRIENT REGIMES ACCORDING TO THEIR NUTRITIONAL

REQUIREMENT

Mints are susceptible to micronutrient limitation rather than to macronutrient deficiency.

LETTUCE > MINT > MUSHROOM HERB

Mushroom herbs seem to be inhibited by high nutrient concentration

The nutrient supplementation improved the speed of growth in lettuce.

Discussion

IT IS PIVOTAL TO KNOWN THE NUTRITIONAL PLANTS REQUIREMENT IN ORDER TO OPTIMIZE

COSTS AND USES OF FERTILIZERS IN AQUAPONICS

Conclusion

A HIGHER MANAGEMENT AND ECONOMIC EFFORT IS NOT ALWAYS

RELATED TO AN OPTIMAL PLANT GROWTH AND QUALITY

In some cases the nutrient supplementation can result in a productivity inhibition

(mint and mushroom herb)

The management effort is closely dependent on the plant species cultivated

THANK YOU FOR YOUR ATTENTION