Aquaponics – Vigyan ashram Experience.

Date -15th July 2012.

Introduction –

Aquaponics is, simply integration of hydroponics (cultivation of plants without soil) and aquaculture (fish farming). In aquaponics system water from aquaculture is used as irrigation water for crop production and extra water returns back to fish tank. When this water circulated near root zone, nitrogen fixing bacteria (manly nitrosomonas and nitrobactor) convert ammonia (NH4) in to nitrite (NO2) and then to nitrate (NO3) form, which is very good source of nitrogen for plants and less toxic to fish in aquaculture system as compare to ammonia. A part from this, aquaculture water is also very good source of almost all macro/ micro nutrient required for plant growth. So this is completely self sustainable system of crop & fish production where about 90 % of the water and 100 % nutrients are recycled for organic crop production.

Source of diagram: -http://www.pondtrademag.com/articles/ar-243/

A trial experiment on feasibility aquaponics technique in Indian context was conducted in Vigyan ashram, Pabal during July 2011to July 2012. Initial small prototype model based on NFT (Nutrient Film Technique) was establish to study basic concept of aquaponics with around 500 lit water tank and hydroponically grown leafy vegetables ( Photo No 1). With around 6 months trial experiment, this is been found that with proper implementation, aquaponics technique can be effectively used in Indian conditions with local fish species. Urban/semi-urban farming and farmers those who have adopted farm tank technique and wish to implement aqua farming (sweet water fish farming) in plastic paper lined farm tanks can adopt aquaponics technique easily.

Aquaponics System details-

Considering scope of aquaponics, we decided to design new system as a terrace gardening model for leafy / fruit vegetables and common carp fish fingerlings (Photo No 2). System details are as given below –

• As shown in figure above system was consist of 2 fish tanks of 500 lit storage capacities each and 6 growing beds of 9 cu ft each (total growing bed of 54 cu ft area).

• Water from fish tank was pumped by 0.75 Hp motor (with discharge of 4LPM) to auto flush tank from which it was distributed to growing beds through 0.75 inch PVC pipes which are having peroration for even distribution of water.

• To each growing bed drain was provided through which water get back to fish tank and circulation of water gets completed (Photo No2, 3&4).

• Each half cut blue barrels (growing beds) were filled with layer of - 2 inch sand gravels and 5 inch vermicompost + coco pit (50:50) as growing media.

• Mixture of soybean balls (grind) + granular fish feed (with 45 % protein) @ 5:1 ratio was used as fish feed @ 30 – 40 gm/day.

• Vegetables like spinach, tomato, Bitter gourd, cabbage, cauliflower were planted in each growing bed as mixed farming system.

• Hydroponics system consisting 3inch PVC pipes with flowering crops like merry gold was also fixed so as to provide extra aeration for fish tank (Photo No 5).

Experiment details –

• Experiment started on 18th March 2012 with 300 fingerlings (200 added after 20 days) of Common carp fish (2 cm in length) and Tomato / Brinjal / Capsicum/ Chili/ Spinach and Bitter guard in 6 beds.

• Water analysis mainly for Dissolve oxygen / NO2 (Nitrate) / NO3 (Nitrite) and NH4 (Ammonia) was done periodically for deciding water pumping / circulating frequency and fish feed to root surface area ratio (Analysis done by using Prerna lab, Pune handy kits).

• After 2 months of experiment (on 23.May.2012) water analysis with details of micro nutrient availability was carried out from Technext Analytical & Research Laboratory, Pune (Details are shown in Annexure 4).

• Water analysis report (Annexure No. 4) showed that aquaponics water was reach source of almost all nutrients (comparison between varmicompost / varmiwash is also given in same table) but EC, NH4 and COD (Chemical oxygen demand) in fish tank water was higher than prescribed standard of aquaponics where as NO3 level was less.

• Fish growth and plant growth was recorded periodically (Annexure 1 & 2).

• Harvesting of vegetables started on 50th days from start of experiment. Details of harvestings given below (Annexure 3).

• Maintains cost for this system was almost nil with zero plant nutrient cost and all extra water getting back to fish tank. Only 10-15 lit of water / day was added as a top up water in fish tank to mach evapo-transpiration and other water losses during circulation.

Visual Observations –

• Initially fish mortality was very high (5 to 8 fish fingerling died every day) but after fixing submersible motor and hydroponics system for increasing DO in fish tank (from initial 1 ppm to 3 ppm) ,it reduced to marginally.

• Flood and drain system (auto flush valve) with very simple mechanism of pulley & pet bottle works very fine with proper water circulation.

• DO (Dissolve Oxygen) and NH4 (Ammonia) levels need to be monitor specifically as fish fingerlings are very sensitive to these 2 parameters. For Common carp fingerlings this was observed DO level below 1ppm fish mortality increases, bigger size fishes were more sensitive to DO level than smaller ones.(DO above 3 ppm was most suitable)

• If water circulation in growing bed reduced (Less than 2 times in day @ 35- 40 lit / circulation), ammonia level rises to more than 2 ppm in fish tank water develops decay flavor of ammonia and water turbidity increases which is harmful for fish growth.

• Fish fingerlings are very sensitive to water temperature if water temperature increases or decrease by 2-3 degree in 1-2 hrs span, fish mortality increases (Especially if rain water enters or water added in tank in short time frame).

• Plants were growing well in aquaponics system, in particular leafy vegetables and vine crops were growing fast (as they requires more nitrogen to grow) with good yield & quality output compare to fruit vegetable (except – tomato).

• This was also observed that aquaponicaly grown vegetables are having more self life and colors of fruits are very good.

• Because of proper moisture content in growing bed (growing bed automatically maintains vapsa {field capacity} conditions), plant grow very well in aquaponics farming.

• Earthworms grow and multiply with very fast rate in aquaponics system.

Result–

• Almost all table vegetables grow well in aquaponics system especially leafy and succulent stem vegetables like tomatoes/vine crops grows faster and better than fruity vegetables. In all total of 35 Kg fresh vegetables are harvested from system in space of about 3.5 month period.

• High density fish farming in combination of vegetable production could be very good and sustainable project for Indian agriculture, but very few references are available on high density fish farming in India so more experimental studies need to be done for this.

• Fish grow well in aquaponics system but need close monitoring especially they are very sensitive for quality / quantity of fish feed, dissolved oxygen and NH4 level in fish tank. Fish fingerlings grown up to 7.5 Cm ( Photo No- 6 & 7) in span of 3.5 months with about 25 % survival rate.

• Selection of proper fish species is also very important while designing aquaponics system. Fish species tolerant to fluctuating DO / NH4 levels and fast growing are most suitable ones.

Problems faced / corrections required -

A. NH4/NH3 level was still very high that standard prescribed levels, while NO3 level is also less than expected this may be because of following reasons –

1. Root / growing bed surface area are is less than amount of fish waste produced.

2. Vermicopost / vermiwash producing NH4/ NH3 + fish waste.

3. Improper bio-filtration – May be because of less water circulation.

B. Un-even fish growth & fish mortality -

1. Fluctuating DO level in fish tank and more NH4.

2. DO less than prescribed standards – less water circulation because of electrical power failure.

3. COD (Chemical Oxygen Demand) of system was higher than prescribed level which may be due to decaying of fish feed in tanks.

4. Improper fish feeding – Non-availability of proper fish feed & Less tech knowhow about fish feeding.

5. Common carp would be wrong fish species for system – as this fish is bottom feeder and requires specific bottom environment as that of water height / mud / hiding place etc.

• EC of system was recorded as very high which inhibit nutrient mobilization for plants this was mainly due to- vermicompost in growing bed, fish tank water concentration.

• Plant growth –

6. Vegetables like capsicum / brinjal are taking more time to start production than vine / leaf vegetables.

7. Because of vermicompost actual effect of aquaponics was still suspicious.

8. As terrace garden model wind velocity at higher level harms plant growth.

Annexure No 1– Growth of vegetables in Aquaponics system:

Sr.No Date Tomato (Cm) Bitter Guard (M) Brinjal (Cm) Capsicum (Cm)

1 18.03.2012 301.5 (Flowering started) 18 20

2 27.03.2012 50 3 2522 (Flowering started)

3 12.04.201265 (Flowering started) 6 (Approx) 32 28

4 25.04.2012 80 9(Approx)50 (Flowering started)

28 ( Stunted growth)

5 6.05.2012 90 15(Approx) 55 306 3.06.2012 90 …. 60 307 23.06.2012 105 … 68 308

Annexure No 2 – Growth of fish in Aquaponics system:

Sr No Date Fish length (Cm)

1 18.03.2012 2

2 18.04.2012 5

3 10.05.2012 6

4 6.07.2012 7.5Annexure No 3 – Vegetable’s harvested from Aquaponics System:

Sr.No Vegetable Quantity harvested ( Approx Kg) Remark

1 Tomato 10Tomato’s are harvested at full grown unripe stage

2 Spinach 5

With spinach coriander and lettuce was also grown used as salad crop

3Bitter Guard 7

Vine growth and fruit size was very good

4Capsicum/ Chili 2

Chilies are more adaptive than capsicums

5 Cabbage 3 6 Cauliflower 4 7 Okra 2.5 Every alternate harvesting

Brinjal 1Vegetative growth is very good but fruiting is less

Annexure No 4 – Water Analysis report of Aquaponics system:

Sr.No Parameters Unit

Aquaponics water ( Technext lab, Pune)

Prerna Kit Analysis

Bench mark for Aquaponics Vermiwash Vermicompost

1 Ph 7.36 7 to 9 7.11* 6.12*

2 EC dSm-1 2.4 21.3***

3 Nitrogen Mg/Lit 224 0.02 (%)** 1.11(%)*

4 NO3 - N Mg/Lit 2.94 < 5 ppm $ 0.1 24 Mg / lit**

5 NH4-N Mg/Lit 16.8(15.85NH3) 1.5-2.0ppm $ 1 25 Mg/ lit^

6 P2O5 Mg/Lit 42.43 12.82mg/lit^ 597(ppm) *

7 K2O Mg/Lit 129.6 2220mg/lit^ 2428.33(ppm) *

8 Calcium Mg/Lit 229 3875mg/lit^ 322.33(ppm) *

9 Magnesium Mg/Lit 97 1225mg/lit^ 137.33(ppm) *

10 Sulphur Mg/Lit 3.16 283mg/lit^

11 Total Iron Mg/Lit 4.19 400mg/lit^

12 Iron (Fe++) Mg/Lit <0.5 2.21(ppm)* 0.11(ppm) *

13 Manganese Mg/Lit <0.1 2mg/lit^ 0.69(ppm) *

14 Zinc Mg/Lit 0.24 5 mg/lit^ 2.13(ppm) *

15 Copper Mg/Lit <0.05 2mg/lit^ 0.01(ppm) *

16 Sodium Mg/Lit 244 1610mg/lit^

17 COD 350 ppm #Note –

#- Tested by Mr.Arun Dixit.

$-Tested periodically by using Prena Pvt.Ltd, Pune (Mahashatra), testing kit.

*- Reference -Abdula Ali Ansari and Kumar Sukhraj 2 july 2010.

**- Reference Sci. & Cult. 77 (9–10) 425-428 (2011).

^- Reference – www.aaqua.com.

Photo No 1 – NFT based Aquaponics. Photo No 2 – Terrace garden model.

Photo No 3 – Terrace garden model (15 days) Photo No 4 - Terrace garden model (30 days)

Photo No 5 – Hydroponics NFT system Photo No 6 – Vegetables in flowering/fruiting.

Phot No 7 – Common carp fish (3 months old) Photo No 7 – Common Carp fish. (3.5 months old.)