Quartz 5

Comparison between Indian spinach production in aquaponics utilizing fish wastewater and hydroponics biogas slurry solution

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tagsmeta/type/experiment, meta/region/south-asia, meta/fish/tilapia, meta/plant/indian-spinach

22 min read

Comparison between Indian spinach production in aquaponics utilizing fish wastewater and hydroponics biogas slurry solution

Metadata

  • Cite key: akterComparisonIndianSpinach2025
  • Item type: Journal Article
  • Authors: B. Akter, F. Akhter, S. Hashem, M.H. Rahman, H. Yeasmin, S.M. Rayhan
  • Affiliation: Dept. of Aquaculture, Khulna Agricultural University; Ministry of Fisheries and Livestock (Bangladesh); Dept. of Aquaculture, Bangladesh Agricultural University; Dept. of Agricultural Statistics, Khulna Agricultural University; Interdisciplinary Institute for Food Security, Bangladesh Agricultural University
  • Journal: Journal of Fisheries 13(3) (2025) Article 133211
  • Date: 12/2025 (published online 7 Dec 2025)
  • Date added: 2026-07-15
  • DOI: 10.17017/j.fish.1145
  • Funding: [not reported]
  • URL: https://doi.org/10.17017/j.fish.1145
  • PDF: Akter et al. - 2025 - Comparison between Indian spinach production in aquaponics utilizing fish wastewater and hydroponics.pdf

Opinion

A clean small-scale side-by-side comparison (3 replicate beds/treatment, defined stats), but the manuscript itself is sloppy: the study duration is stated as four different numbers in four different sections (98 / 92 / 90 / 97 days) with no way to tell which is right, the fish initial length/weight is given two different ways (abstract+Table 4 vs. Discussion — though this one is resolvable by arithmetic), the fish tank volume is self-contradictory in the same sentence (750 L vs “0.46 m³”), and the abstract claims a “significant” potassium result the paper’s own table marks “ns”. None of this is necessarily fatal to the qualitative finding (aquaponics > hydroponics on most metrics), but every number should be re-verified against the primary tables before citing, not taken from the abstract or Discussion prose.

Abstract

The experiment compared Indian spinach production in aquaponics utilizing fish wastewater and hydroponics with biogas slurry solution. The aquaponics system involved 60 juvenile tilapias, released into a 750 L tank with an average initial length and weight of 14.41 ± 0.66 cm and 49.81 ± 4.29 g, respectively. The fish were fed commercial pelleted feed twice daily and maintained suitable water quality parameters, including pH, temperature, and DO, within the required range. The hydroponics system used biogas slurry as nutrient media. In each system, 3 plant beds were used, and 4 Indian spinach plants were planted in each bed. Physical parameters of water indicated that the aquaponics system had higher levels of EC, HCO3, CO3, Total-N, potassium, sulphur, and sodium than the hydroponics system. After 90 days, aquaponics had the largest plant weight (82.05 ± 23.31 g), with significantly higher levels of nitrogen, potassium, and sulphur content (by 5.54%, 3.10%, and 0.61% respectively) in leaves was found in aquaponics, while the phosphorus (0.85%) was higher in hydroponics. The yield of Indian spinach was higher in aquaponics (2.88 kg m–2) than in hydroponics (1.52 kg m–2). Length gain of experimental fish in aquaponics was 10.54 ± 1.51 cm, weight gain 112.71 ± 21.75 g, with a percent weight gain of 227.23 ± 42.98, specific growth rate of 1.4 ± 0.16% day–1, which was normal. The study concluded that wastes from tilapia aquaponics are more suitable for Indian spinach cultivation than low-cost biogas slurry hydroponics.

Summary

The authors ran a small side-by-side trial at Bangladesh Agricultural University: one 750 L tilapia tank feeding an aquaponic bed system (3 replicate jerry-can beds, bricklet medium, 4 Indian spinach plants/bed) versus a separate hydroponic system fed with diluted biogas slurry instead of fish water (same bed design, 3 replicates). Water quality (pH/temp/DO) was tracked in the fish tank across the cycle, and influent/effluent nutrient chemistry (EC, CO3, HCO3, Total-N, P, K, S, Na) was compared for both systems in two snapshot months (July, September). Indian spinach grown on fish wastewater came out ahead on every plant metric measured — height, leaf count, plant weight, yield per m², and leaf N/K/S% — except phosphorus, which was higher in the hydroponic (biogas slurry) leaves. Fish grew from ~50 g to ~163 g over the trial with an FCR of 1.85 and 96.67% survival. The paper does not report any inferential statistics comparing the fish growth curve to anything (there is no fish control), so the fish-side numbers are purely descriptive; only the plant/water comparisons carry significance tests.

Experiment data

  • Location: Aquaponics Laboratory, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh, Bangladesh
  • Design: 2 treatments (T1 aquaponics / T2 hydroponics) × 3 replicate beds each, no randomisation statement given for bed assignment
  • Replicates / n: 3 beds/treatment (4 plants/bed, 24 seedlings total); fish: single 750 L tank, no fish-side replication
  • Duration: ⚠️CHECK — see Fish trial duration contradiction below; paper gives 98 (Methods, “14 weeks”, likely setup window), 92 (Table 1 date range, from fish stocking), 90 (Table 4 / Results / Discussion, repeated — fish culture period), and 97 days (Conclusion, likely whole investigation). Recorded as 90 in trials.csv, tied to the reported growth/production stats.
  • Organisms: Tilapia (species not specified in text) / Indian Spinach (Basella alba)
  • Statistics: Unpaired t-test with Welch’s correction (plant growth & water-quality comparisons); Multiple unpaired t-test + Holm-Šídák multiple comparison (influent vs. effluent); linear regression (fish length/weight over time); GraphPad Prism (2024)
  • Plant height: AP 18.37 cm vs HYD 15.47 cm (significantly higher in AP, p<0.05) — overall/final comparison (Discussion 4.6); per-sampling-date values exist only in Figure 3A bar charts, not restated in text → NR
  • Leaf count: AP 15.52 vs HYD 12.07 leaves/plant (Discussion 4.6)
  • Feed Conversion Rate (FCR): 1.85 ± 0.37
  • Specific Growth Rate (SGR): 1.4 ± 0.16 %/day

Water quality

This paper: Fish tank pH 7.8 ± 0.267 (range 7.57–8.43), temperature 28.69 ± 0.737 °C (range 27.67–29.63), DO 4.21 ± 0.418 mg/L — all genuine trial means from Table 1 (7 sampling dates across the cycle). EC has no overall trial mean anywhere in the paper — it only appears in the July/September influent-effluent snapshot matrix (Tables 2–3): aquaponics EC ranged 338–598 µS/cm across the four cells (July inf. 394±13, July eff. 338±11, Sept inf. 598±17.5, Sept eff. 369±9.5). Recorded as a range, not averaged. TAN/NH4-N was not measured at all (absent from the Methods 2.8 parameter list). NO2-N and NO3-N were measured per Methods 2.8 (Hach DR4000, diazotization/cadmium reduction methods) but the Results only ever report the aggregated “Total-N” — the individual nitrite/nitrate figures are never given, so both are NR despite being measured.

Compared with:

Fish growth

This paper: Initial weight 49.81 ± 4.29 g → final 162.52 ± 23.03 g (Table 4/Abstract value — see contradiction note); weight gain 112.71 ± 21.75 g; % weight gain 227.23 ± 42.98; SGR 1.4 ± 0.16 %/day; FCR 1.85 ± 0.37; survival 96.67%; condition factor 1.04 ± 0.06 (no column in schema — plant_measurements.csv is plant-only and trials.csv has no CF field; recorded only here and in Experimental Remarks).

Compared with:

Leaf nutrient content and yield

This paper: N, K, S all significantly higher in aquaponic leaves (Table 5); P significantly higher in hydroponic leaves — except “significantly higher” is wrong for K per the table’s own marking (⚠️MATERIAL, see below). Yield: aquaponics 2.88 kg/m² vs hydroponics 1.52 kg/m² (consistent between abstract and Results body text, and internally consistent with the stated 1.33 kg / 0.462 m² and 0.70 kg / 0.462 m² figures — recomputed and confirmed: 1.33/0.462=2.88, 0.70/0.462=1.52).

Compared with:

  • todo Sayara et al. 2016 — fish-waste nutrients don’t match hydroponic-solution N/P/K/S/Ca/Mg/Fe levels (p. 2, secondary claim)
  • todo Hossain et al. 2014 — Indian spinach height 9.42–29.33 cm on biogas slurry at 30/60 DAS (p. 9, Discussion 4.6)
  • todo Roy et al. 2013 — similar mean Indian spinach weight in aquaponics (p. 9)

Linked claims

Citations to chase

  • todo Stone and Thomforde (2004) — EC/water-quality acceptable ranges for pond fish culture
  • todo Boyd (1998) — pond-culture acceptable ranges for CO3/HCO3/P/Na/K/S
  • todo DeLong et al. (2009) — tilapia pH/temperature tolerance
  • todo Sayara et al. (2016) — fish-waste vs hydroponic-solution nutrient comparison
  • todo Hossain et al. (2014) — Indian spinach growth on biogas slurry
  • todo Hossain et al. (2022) — planting density optimization, Indian spinach aquaponics
  • todo Roy et al. (2013) — aquaponics polyculture pond feasibility
  • todo Akter et al. (2018) — tilapia + water spinach aquaponics, Bangladesh

Extraction notes

  • ⚠️CHECK (reclassified from ⚠️BLOCK) — Fish trial duration. Four different figures given across the paper: Methods 2.1 states “14 weeks (from 19th May to 5th September)” = 98 days by unit conversion, but the stated date range (19 May–5 Sept) itself spans 109 days — internally inconsistent before any cross-section comparison, and most plausibly reflects the EXPERIMENTAL SETUP window (bed preparation, seedling raising) rather than fish culture. Table 1’s own sampling dates run Day 1 (5-Jun-23) to Day 7 (5-Sep-23) = 92 days — this starts at FISH STOCKING. Table 4’s caption and Results 3.4 both label production “kg/m3/90 days”, and Discussion 4.4 explicitly states “The tilapia culture was conducted for 90 days” (repeated 3×) — this is the FISH CULTURE period the growth/production stats are computed over. The Conclusion states “This study only covered up only 97 days of investigation” — plausibly the FULL INVESTIGATION window including setup and analysis. On reflection these look like four genuinely different intervals (setup, stocking-to-harvest, fish-culture-proper, whole study) that the paper never explicitly reconciles, not four incompatible measurements of the same interval — the textbook CHECK case, not BLOCK. Fish trial duration (days) recorded as 90, the value tied directly to the reported growth/production statistics (FCR, weight gain, yield all stated “over 90 days” in Table 4); the other three candidates are recorded in trials.csv remarks and REVIEW.md for anyone whose analysis needs a different definition.

    RESOLVED BY USER (2026-08-05, via REVIEW.md). The user reviewed this item and confirmed 90 days, on the reasoning that the other three figures (98, 92, 97) are measurements taken at different dates/phases of the study rather than competing values for the same interval. This matches the value this extraction had already chosen on CHECK-tier grounds — it is now the user’s confirmed resolution, not just this extraction’s inference.

  • ⚠️MATERIAL — Fish initial length/weight. Abstract and Table 4 agree: 14.41 ± 0.66 cm / 49.81 ± 4.29 g. Discussion 4.4 gives different numbers for “the current study”: 15.02 ± 1.19 cm / 52.09 ± 2.1 g. Resolved by arithmetic, not just majority-vote: Table 4’s own final length (24.95 cm) minus its own length gain (10.54 cm) = 14.41 cm exactly, and final weight (162.52 g) minus weight gain (112.71 g) = 49.81 g exactly — both match the Abstract/Table 4 initial values precisely and do NOT match Discussion’s initial values (15.02 cm would imply final 25.56 cm; 52.09 g would imply final 164.80 g; neither matches Table 4’s stated finals). 14.41 ± 0.66 cm and 49.81 ± 4.29 g recorded as Fish size initial; Discussion’s figures are almost certainly a copy-paste error from a different trial/manuscript draft.

  • ⚠️MATERIAL — Potassium significance. Abstract: “significantly higher levels of nitrogen, potassium, and sulphur content… in aquaponics.” Table 5 explicitly marks Potassium ns (not significant) — only Nitrogen and Sulphur are marked *. The table carries its own defined significance levels (t-test with Welch’s correction, ///ns) and is the primary data source; the abstract’s blanket claim appears to have conflated K with N and S. Table 5’s ns marking used for the Potassium row in plant_measurements.csv; abstract claim noted as the conflicting source.

  • ⚠️MATERIAL — Fish tank volume. Methods 2.3.1: “A 750-liter (0.46 m³) plastic water tank” — 750 L = 0.75 m³, not 0.46 m³, a self-contradiction within one sentence. Resolved by cross-check: stocking density is given as “80 fish/1000-L” and 60 fish were stocked; 80 × (750/1000) = 60, exactly matching the stated stock count. The Table 4 production figures also cross-check against 0.75 m³, not 0.46 m³ (7.47 kg/tank ÷ 0.75 m³ = 9.96 kg/m³, matching the stated “Production kg/m³/90days” value exactly). 750 L / 0.75 m³ recorded; “(0.46 m³)” is very likely a typo for “(0.75 m³)”.

  • ⚠️MINOR — Survival rate. Table 4 states 96.67%; Discussion 4.4 restates it rounded to “96%”. Table 4’s more precise value (96.67%) recorded.

  • ⚠️MINOR — Fish production recompute mismatch. Recomputing “fish harvested × mean weight gain” per the paper’s own formula (Methods 2.3.3) as a check: 60 fish × 0.9667 survival ≈ 58 harvested × 112.71 g weight gain ≈ 6.54 kg, versus the stated Table 4 production of 7.47 kg/tank — about 14% off. Origin of the discrepancy is unclear (possibly unrounded intermediate values not shown). Not flagged as BLOCK/MATERIAL because the stated 7.47 kg figure is taken as-is (not derived by this extraction) and the mismatch doesn’t affect any other cell; noted for anyone downstream trying to reconcile the fish-production numbers.

  • [not reported]: Total Feed (kg) — FCR and weight gain are both given, allowing later derivation, but total feed mass itself is never stated. Stocking density in kg/m³ (only fish/L density given: 80 fish/1000 L). Plant dry matter — Methods 2.6 describes oven-drying and weighing plants, but no dry-weight/dry-matter numbers appear anywhere in Results, Discussion, or the tables. SPAD/chlorophyll — not measured at all. Plants/m² — 4 plants/bed and 0.154 m²/bed are both given but dividing them would be derivation, not extraction. Lat/Long — not stated anywhere in the text (university address given, but no coordinates in the paper itself, and CLAUDE.md prohibits filling this from background knowledge). Fish species (Latin binomial) — paper uses “tilapia” throughout for its own fish and never assigns a species name to its own stock (Latin binomials appear only in citations of other authors’ work).

  • [unclear]: Whether “liming” during fish-tank preparation (Methods 2.3.1: “cutting, cleaning, and liming”) is a one-time tank-curing step or an ongoing pH-buffering practice — read as one-time tank prep, so pH Buffers = NR rather than Y. Whether “Biological system already in use” applies: the 60 fish came “from a previous lab aquaponics experiment” (Methods 2.3.2), but this describes fish sourcing, not whether the tank’s own nitrifying biofilter was already established/cycled before this trial — no direct statement either way, so recorded NR rather than guessing Y.

  • NO COLUMN (trials.csv / plant_measurements.csv have no field for these): Condition factor 1.04 ± 0.06 (Table 4). Daily growth rate 1.34 ± 0.26 g/day (Table 4). Water Total-N, P, K, S, Na, CO3, HCO3 from the influent/effluent matrix (Tables 2–3) — no dedicated water columns beyond TAN/NO2-N/NO3-N/EC exist in trials.csv; full monthly grids left in the tables themselves, only EC’s range was pulled into its column. Leaf area (cm², Figure 3C) — no schema column for leaf area, and values are figure-only anyway (no text/table number given) so would be NR even if a column existed.

  • Figure-only → NR: Per-sampling-date plant height, leaf number, and leaf area values (Figure 3A/B/C) — only the overall/final comparison numbers stated in Discussion 4.6 (18.37/15.47 cm height; 15.52/12.07 leaf count) were used; the six-timepoint bar values are never restated in text/table. Aquaponic plant weight on 02-Jul-23, and both systems’ plant weight on 02-Aug-23 (Figure 4A) — only 02-Sep-23 (both systems) and hydroponic 02-Jul-23 (“lowest weight”) are restated in Results 3.6 text. Individual biweekly fish total-length/body-weight data points (Figure 2) — only the regression equations are given; Table 4’s initial/final summary values were used instead.

  • UNIT CONVERSION ONLY: 14 weeks → 98 days (Methods 2.1, one of the four duration candidates — see CHECK note above); 750 L → 0.75 m³ (cross-checked, see MATERIAL note above); µS/cm → dS/m for the EC range (338–598 µS/cm ≈ 0.338–0.598 dS/m).

  • Candidate wikilink targets needing vault check (not yet resolved to a canonical form): [[Feed Conversion Rate (FCR)]] vs [[FCR]]; [[Specific Growth Rate (SGR)]] vs [[SGR]]; [[Indian Spinach (Basella alba)]] vs [[Basella alba]] vs [[Indian Spinach]]; [[Tilapia]] — species unspecified in this paper, so cannot link to a species-level tilapia note if the vault distinguishes by species.

Source: Akter et al. - 2025 - Comparison between Indian spinach production in aquaponics utilizing fish wastewater and hydroponics.pdf

Data Tables

Structured data extracted from this paper into the vault's trials.csv / plant_measurements.csv datasets. Fields the paper didn't report are omitted. Download the full datasets (measurements).

Trial Parameters

akterComparisonIndianSpinach2025-T1

Fish

FieldValue
FishTilapia, juvenile fry (species not specified in text)
FCR1.85 +/- 0.37
SGR1.4 +/- 0.16
Protein30
% of body weight3
Fish size initial49.81 +/- 4.29
Fish size final162.52 +/- 23.03
Feed routineTwice daily
Feed regimeCommercial floating pelleted feed, 30% protein, at 3% of body weight/day, twice daily; overfeeding avoided
Fish biomass created (kg)7.47
Fish survival rate96.67
Fish weight gain112.71 +/- 21.75
Fish trial duration (days)90

Water

FieldValue
Water volume in the system750
Water typeClean water (overhead tank supply, initial fill)
Aq pH7.8 +/- 0.267
Dissolved Oxigen4.21 +/- 0.418
EC338-598 (range only, no trial mean reported; microS/cm, approx 0.338-0.598 dS/m)
Water temperature28.69 +/- 0.737

Plant

FieldValue
PlantIndian spinach (Basella alba)
DetailsSeedlings germinated in soil, transplanted 4/bed into jerry-can grow beds with bricklet medium; 3 beds/treatment; watered 3x daily with fish-tank water (AP) or biogas slurry (HYD)
Plant CategoryLeafy vegetable (p.2)
Plant height18.37
Leaf count15.52
Plant fresh weight59.25

System & Setup

FieldValue
Media DetailsPlastic food-grade jerry cans (44x35x14 cm, 0.02156 m3) cut into pore-shaped outlets, filled with bricklets (not soil); bed surface area 0.154 m2 each; 3 beds/treatment
Air supplementY (Four air stones + two 10-watt air pumps in fish tank)
Nutrient supplementedY (Hydroponic treatment: biogas slurry solution (collected from Cattle Farm biogas plant, diluted with distilled water, refilled weekly) as sole nutrient medium; Aquaponic treatment: fish wastewater only, no chemical fertilizer added (Methods 2.5))
Equipment750 L (0.75 m3) plastic fish tank with 7.6cm gravel base, 25-W submersible pump + mesh-covered filter bowl, 4 air stones + two 10-W air pumps (aquaponics); 0.11 m3 plastic barrel with 12-W pump (hydroponics biogas-slurry tank); food-grade jerry can grow beds (44x35x14cm) with bricklet medium; PVC piping; HANNA HI-98194 multiparameter meter (pH/DO/temp/EC); Hach DR4000 spectrophotometer (Total-N, NO2-N, NO3-N, TP, K); flame atomic emission spectrophotometer (leaf K); Kjeldahl method (leaf N); GraphPad Prism (2024)
Control ParametersTwo treatments (T1 aquaponics, T2 hydroponics), 3 replicate beds each (T1R1-3, T2R1-3); unpaired t-test with Welch’s correction for plant/water comparisons; multiple unpaired t-test with Holm-Sidak correction for influent vs effluent changes
CombinationTilapia and Indian spinach (Basella alba); aquaponics (fish wastewater) vs hydroponics (biogas slurry solution)

Site

FieldValue
RegionSouth Asia
CountryBangladesh

Results & Statistics

FieldValue
Measured Unitkg/m2 (yield); % dry leaf tissue (N,P,K,S); cm (plant height); count (leaf number); g/plant (plant weight)
Statistic DetailsUnpaired t-test with Welch’s correction (plant growth, water quality); Multiple unpaired t-test + Holm-Sidak multiple comparison (influent vs effluent); linear regression (fish growth); GraphPad Prism 2024
Statistically analysedY
Replicates (n)3
AP2.88
HYD1.52

Experimental Remarks: TRIAL DEFINITION: T1 = aquaponic treatment (Indian spinach on tilapia fish wastewater). Paired control = hydroponic treatment (T2) on biogas slurry solution, recorded in HYD columns. Only one aquaponic treatment in this paper (3 replicate beds), so one row. | RESOLVED BY USER (2026-08-05, via REVIEW.md): Fish trial duration. Four figures given across the paper — 98 d (Methods 2.1, ‘14 weeks from 19-May to 5-Sep’, itself internally inconsistent with the 109-day span of those same calendar dates), 92 d (Table 1 sampling window, starts at FISH STOCKING), 90 d (Table 4 caption + Results 3.4 + Discussion 4.4, repeated 3x — the FISH CULTURE period the growth/production stats are computed over), 97 d (Conclusion — reads as the FULL INVESTIGATION window). The user reviewed this and confirmed: use 90 days; the other three figures are measurements taken at different dates/ phases of the study, not competing values for the same interval. Fish trial duration (days) recorded as 90, tied directly to the reported growth/production statistics (FCR 1.85, weight gain 112.71 g, yield 7.47 kg/tank and 9.96 kg/m3, Table 4, all stated ‘over 90 days’). This confirms the extraction’s own prior CHECK-tier choice of 90; it is now the user’s resolution, not just this extraction’s inference. | WARN-MATERIAL Fish initial size: abstract and Table 4 agree (14.41 +/- 0.66 cm / 49.81 +/- 4.29 g); Discussion 4.4 gives different values for ‘the current study’ (15.02 +/- 1.19 cm / 52.09 +/- 2.1 g). Resolved by recompute, not just majority vote: Table 4 final length (24.95) minus its own length gain (10.54) = 14.41 exactly; final weight (162.52) minus weight gain (112.71) = 49.81 exactly — both match abstract/Table 4’s initial values and do NOT match Discussion’s (15.02+10.54=25.56, not 24.95; 52.09+112.71=164.80, not 162.52). 14.41 +/- 0.66 cm / 49.81 +/- 4.29 g recorded; Discussion’s figures are likely a copy-paste error from elsewhere. | WARN-MATERIAL Potassium significance: abstract claims ‘significantly higher levels of nitrogen, potassium, and sulphur’ in aquaponic leaves; Table 5 explicitly marks Potassium ‘ns’ (only N and S are starred). Table 5’s own marking used for the plant_measurements.csv Potassium/AP-HYD row; abstract claim noted as the conflicting source, likely conflating K with N/S. | WARN-MATERIAL Fish tank volume: Methods 2.3.1 states ‘750-liter (0.46 m3)’ in one sentence — 750 L = 0.75 m3, not 0.46 m3. Cross-checked two ways: stocking density is given as 80 fish/1000-L and 60 fish were stocked (80 x 0.75 = 60, matching exactly); Table 4 production of 7.47 kg/tank divided by 0.75 m3 = 9.96 kg/m3, matching the paper’s own stated per-m3 production figure exactly (dividing by 0.46 m3 would give 16.24, not matching). 750 L / 0.75 m3 recorded; ‘(0.46 m3)’ is almost certainly a typo for ‘(0.75 m3)’. | WARN-MINOR Survival rate: Table 4 gives 96.67%; Discussion 4.4 rounds it to ‘96%’. Table 4’s precise value used. | WARN-MINOR Fish production recompute check (verification only, not entered in any cell): 60 fish x 96.67% survival is about 58 harvested x 112.71 g weight gain is about 6.54 kg, versus the stated Table 4 production of 7.47 kg/tank (roughly 14% off, origin unclear). Stated 7.47 kg used as-is in Fish biomass created. | UNIT CONVERSION ONLY: 14 weeks -> 98 days (one of the four BLOCK duration candidates, Methods 2.1); 750 L -> 0.75 m3 (cross-checked, see MATERIAL note above); EC range 338-598 microS/cm converted to approx 0.338-0.598 dS/m. | NOT DERIVED, left NR: Initial Stock density (paper gives 80 fish/1000-L, i.e. individuals/m3, not the kg/m3 the schema requires); Total Feed kg (FCR 1.85 and weight gain 112.71g both given — would allow derivation later under one consistent method, not derived here); Plants/m2 (4 plants/bed and 0.154 m2/bed both given, not divided here); SPAD (not measured at all — no chlorophyll meter mentioned anywhere); Plant dry matter (oven-drying and precision-balance weighing described in Methods 2.6, but no dry-weight or dry-matter percentage numbers appear anywhere in Results, Discussion, or the tables); Tissue nitrate AP/HYD (leaf N/P/K/S percent measured via Table 5, not nitrate specifically); Lat/Long (university address given, no coordinates stated anywhere in the paper itself). | Fish Category, Water classification, System type, pHOptimal, Average room Temperature, Biological system already in use all NR — paper does not categorise or state these; fish are called only ‘tilapia’ throughout with no Latin binomial applied to the study’s own stock (species names appear only in citations of other authors’ fish). | Water quality: TAN/NH4-N was not among the parameters measured at all (absent from the Methods 2.8 parameter list). NO2-N and NO3-N WERE measured per Methods 2.8 (Hach DR4000 spectrophotometer, diazotization/cadmium-reduction methods) but only the aggregate ‘Total-N’ is ever reported in Results/Tables 2-3 — individual nitrite/nitrate figures never appear, so both are NR despite being measured. EC has no overall trial mean stated anywhere in the paper — it appears only in the July/September influent-effluent snapshot matrix (Tables 2-3); recorded as the range across the 4 aquaponics cells (338-598 microS/cm: July influent 394+/-13, July effluent 338+/-11, September influent 598+/-17.5, September effluent 369+/-9.5) per the ‘range only, no trial mean reported’ rule — not averaged by this extraction. | Plant height/Leaf count/Plant fresh weight columns hold the AQUAPONIC value only (18.37 cm / 15.52 leaves / 59.25 g/plant, all from Discussion 4.6 overall/final comparisons, not from the per-sampling-date figures); the paired HYDROPONIC values for the same three metrics were 15.47 cm / 12.07 leaves / 31.23 g/plant (also Discussion 4.6) — there is no HYD-paired column for these three fields, unlike Tissue nitrate AP/HYD, so the HYD figures live only here. | Figure-only, recorded NR per the new figure rule: per-sampling-date plant height, leaf-number, and leaf-area values (Figure 3A/B/C) beyond the Discussion’s overall/final summary numbers used above; aquaponic plant weight on 02-Jul-23 and both systems’ plant weight on 02-Aug-23 (Figure 4A) — only 02-Sep-23 (both systems) and hydroponic 02-Jul-23 (‘lowest weight’) are restated in Results 3.6 body text; individual biweekly fish total-length/body-weight data points (Figure 2) beyond Table 4’s initial/final summary — only the regression equations (Y=0.7784X+14.16, p=7.573e-028; Y=8.389X+38.93, p=4.276e-009) are given in text, no raw points. | NO COLUMN: Condition factor (CF) 1.04 +/- 0.06 (Table 4) — no field in trials.csv or plant_measurements.csv (the latter is plant-tissue only). Daily growth rate 1.34 +/- 0.26 g/day (Table 4). Water Total-N/P/K/S/Na/CO3/HCO3 influent-effluent values (Tables 2-3, July and September, both aquaponics and hydroponics systems) — no dedicated water columns exist beyond TAN/NO2-N/NO3-N/EC; representative aquaponics Total-N figures: influent 4.20+/-0.99 ppm (July) / 11.2+/-1.02 ppm (September), effluent 7.00+/-0.7 ppm (July) / 5.6+/-0.70 ppm (September); full grids remain in Tables 2-3 of the source PDF only. Production kg/m3/90days = 9.96 (Table 4) — shares the duration BLOCK uncertainty as its denominator.

Plant Measurements

TrialSystemCategoryAnalyteValueUnitSig.Location
akterComparisonIndianSpinach2025-T1APmineralNitrogen5.54 ± 0.95% dry leaf tissue*Table 5
akterComparisonIndianSpinach2025-T1HYDmineralNitrogen3.42 ± 0.49% dry leaf tissue*Table 5
akterComparisonIndianSpinach2025-T1APmineralPhosphorus0.78 ± 0.16% dry leaf tissuensTable 5
akterComparisonIndianSpinach2025-T1HYDmineralPhosphorus0.85 ± 0.26% dry leaf tissuensTable 5
akterComparisonIndianSpinach2025-T1APmineralPotassium3.10 ± 0.25% dry leaf tissuensTable 5
akterComparisonIndianSpinach2025-T1HYDmineralPotassium2.49 ± 0.42% dry leaf tissuensTable 5
akterComparisonIndianSpinach2025-T1APmineralSulphur0.61 ± 0.21% dry leaf tissue*Table 5
akterComparisonIndianSpinach2025-T1HYDmineralSulphur0.05 ± 0.01% dry leaf tissue*Table 5

Graph View

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