Net Yield Research Articles

Prey diversity constrains the adaptive potential of predator foraging traits

Predators are generally under selective pressure to get better at foraging, leading to steeper functional responses and stronger predator–prey interactions. Yet strong interactions can de‐stabilize food webs, and most interactions across ecological communities are thought to be weak. This conflict between evolutionary and community expectations for the strength of predator–prey interactions represents a fundamental gap in our understanding of how the evolution of foraging plays out in food webs. Here we help to resolve the conflict by showing analytically that the expectation for the evolution of steeper functional responses is relaxed in communities with diverse prey types. We simulate communities with varying prey richness and show that increasing prey richness can indeed constrain the adaptive potential of predator foraging traits, but that at low prey richness predators can evolve to have a stronger interaction with prey that have high net energy yields. Our results also indicate that handling time plays a role in determining whether predators may evolve to have a stronger interaction with abundant prey, suggesting that the evolution of keystone predator modules in food webs is most likely when handling times are negligible. Our results also provide a new mechanism predicting more diffuse interactions in diverse tropical communities relative to more species‐poor communities at higher latitudes.

RESPON PERTUMBUHAN DAN HASIL TANAMAN KAILAN TERHADAP PEMBERIAN KAPUR DOLOMIT DAN PUPUK BOKASHI KOTORAN SAPI DI TANAH GAMBUT

The study aimed to determine the response of growth and yield of kailan on the interaction effect of a dolomite lime with bokashi of cow manure and its single factor effect. The experiment was conducted in Completely Randomized Design (CRD) with two factors in three replications. The first factor was dolomite lime which consists of 2 t ha-1 (k1), 5 t ha-1 (k2), 10 t ha-1 (k3) and 15 t ha-1 (k4), while the second factor was bokashi of cow manure consisting of 0 t ha-1 (b0), 10 t ha-1 (b1), 15 t ha-1 (b2), and 20 t ha-1 (b3). By observing growth components consisting of relatif growth rate (RGR), crop growth rate (CGR), net assimilation rate (NAR), shoot/root ratio (S/R), and crop yield. As well as the components of soil nutrient content of N, P, K, C-organic content, pH and cation exchange capacity (CEC). The results showed that the application of dolomite lime at a dose of 15 t ha-1 with bokashi fertilizer at a dose of 20 t ha-1 give the highest value of crop growth rate (CGR), net assimilation rate (NAR), shoot/root ratio (S/R), C-organic content, phosphorus (P), and Potassium in peat soil. The application of bokashi fertilizer at a dose of 15 t ha-1 was not different with 20 t ha-1 in terms of relatif growth rate (RGR), crop yield and cation exchange capacity (CEC), and respectively higher than the dose of 10 t ha-1 and without bokashi fertilizer. The application of dolomite lime at a dose of 10 t ha-1 was not different with 15 t ha-1 on the relative growth rate (RGR), and pH of peat soil, and each dose was higher than the doses of 5 t ha-1 and 2 t ha-1 . In terms of nitrogen (N) content, the application of dolomite lime at a dose of 5 t ha-1 was not different with the dose of 10 t ha-1 , and 15 t ha-1 , the N content was higher than the dose of 2 t ha-1 . The increase in the dose of dolomite lime at 20 t ha-1 of bokashi fertilizer showed a positive linier correlation, except for the Potassium which showed a quadratic correlation. The increase dose of dolomite lime in the bokashi fertilizer, the plant growth rate (PAR), net assimilation rate (NAR), shoot/root ratio (S/R), C-organic content, and phosphorus (P) would increase as well. Each single factor of the dose of dolomite lime and bokashi fertilizer showed a positive linier relationship to the relatif growth rate (RGR), crop yield, N-total, pH, and cation exchange capacity (CEC) of peat soil, except for N-total and pH in bokashi fertilizer.

An intelligent system for crop identification and classification from UAV images using conjugated dense convolutional neural network

Crop identification and classification is an important aspect for modern agricultural sector. With development of unmanned aerial vehicle (UAV) systems, crop identification from RGB images is experiencing a paradigm shift from conventional image processing techniques to deep learning strategies because of successful breakthrough in convolutional neural networks (CNNs). UAV images are quite trustworthy to identify different crops due to its higher spatial resolution. For precision agriculture crop identification is the primal criteria. Identifying a specific type of crop in a land is essential for performing proper farming and that also helps to estimate the net yield production of a particular crop. Previous works are limited to identify a single crop from the RGB images captured by UAVs and have not explored the chance of multi-crop classification by implementing deep learning techniques. Multi crop identification tool is highly needed as designing separate tool for each type of crop is a cumbersome job, but if a tool can successfully differentiate multiple crops then that will be helpful for the agro experts. In contrast with the previous existing techniques, this article elucidates a new conjugated dense CNN (CD-CNN) architecture with a new activation function named SL-ReLU for intelligent classification of multiple crops from RGB images captured by UAV. CD-CNN integrates data fusion and feature map extraction in conjunction with classification process. Initially a dense block architecture is proposed with a new activation function, called SL-ReLU, associated with the convolution operation to mitigate the chance of unbounded convolved output and gradient explosion. Dense block architecture concatenates all the previous layer features for determining the new features. This reduces the chance of losing important features due to deepening of the CNN module. Later, two dense blocks are conjugated with the help of a conversion block for obtaining better performance. Unlike traditional CNN, CD-CNN omits the use of fully connected layer and that reduces the chance of feature loss due to random weight initialization. The proposed CD-CNN achieves a strong distinguishing capability from several classes of crops. Raw UAV images of five different crops are captured from different parts of India and then small candidate crop regions are extracted from the raw images with the help of Arc GIS 10.3.1 software and then the candidate regions are fed to CD-CNN for proper training purpose. Experimental results show that the proposed module can achieve an accuracy of 96.2% for the concerned data. Further, superiority of the proposed network is established after comparing with other machine learning techniques viz. RF-200 and SVM, and standard CNN architectures viz. AlexNet, VGG-16, VGG-19 and ResNet-50.

Production and compatibility assessment of denitrifying biogranules tailored for self-healing concrete applications

Microbial granules have been mostly used for wastewater treatment. Recently, biogranules consisting nitrate-reducing microorganisms have appeared as a unique healing agent providing simultaneous self-healing of cracks and corrosion inhibition of rebar in concrete. Yet, information about the production process and microbial activity of these biogranules as well as their compatibility with cementitious materials remains unknown. This study presents the biogranule production procedure in detail and evaluates the compatibility of the produced biogranules with the cementitious composites. In the form of biogranules, bacteria doses varying between 0.25% and 3.00% w/w cement were incorporated into mortar and the variations in fresh and hardened properties of mortars were evaluated with respect to abiotic mortars. Biogranules were also tested for their compatibility with concrete at minimum and the defined maximum tolerable doses. Biogranules with a NOx-N reduction activity of 0.10 g NOx-N.g−1 bacteria.d−1 and organic carbon oxidation activity of 1.50 g HCOO⁻.g−1 bacteria.d−1 were produced successfully by using minimal medium. It was found out that biogranules enable bacteria incorporation into mortar up to a dose of 2.50% w/w cement without compromising fresh and hardened properties of cementitious composites. It was revealed that the compatibility of the biogranules was due to the mineral layer surrounding the biogranules which prevented interaction between the cement matrix and the microbial content. The thickness of the protective mineral layer around the granules was varying between 50 and 300 μm depending on the granule size. Net yield for concrete compatible biogranule production was determined as 0.05 g biogranule.g−1 HCOO⁻.

Agricultural wastes co-densification: A solution for seasonal feedstock storage and anaerobic digestion performance improvement

Rice straw and pig manure pellets (RPP) and sorghum straw and pig manure pellets (SPP) were used to identify their competition as the flexible feedstock of anaerobic digestion with one-year indoor storage. The results indicated the effect of time on their characteristic was tiny during storage period, such as density, calorific value, total solid, volatile solid, ratio of carbon and nitrogen, and lignocellulosic components. Biogas yields of stored RPP and SPP were 8.8% and 26.7% lower than that of fresh pig manure (PM), and 45.4% and 56.1% higher than the sum of corresponding straw and PM digestion alone, respectively. Improvements in biodegradability were observed in co-densified biomass anaerobic digestion. Net biogas yield of RPP was 24.2% higher than that of rice straw, considering volatile matter loss and biogas yield decline during densification and storage stage. Priority of manure and supplement of co-densified biomass were proposed for feedstock supply on demand.

Production of bioethanol from wheat straw via optimization of co-culture conditions of Bacillus licheniformis and Saccharomyces cerevisiae

Bioethanol production has been a challenge for the researchers with respect to enhancing the bioethanol yield. In this study, we are reporting an efficient novel method to produce bioethanol. The process comprises co-culture technique to produce bioethanol from wheat straw, by co-culturing Bacillus licheniformis and Saccharomyces cerevisiae. Simultaneous saccharification and fermentation allows wheat straw hydrolysis by cellulase enzyme produced by Bacillus licheniformis and conversion of produced reducing sugar into ethanol by Saccharomyces cerevisiae. Pre-treatment of wheat straw and optimization of co-culturing parameters like, time, pH, substrate concentrations and nitrogen source concentrations gave a net yield of ⁓ 4.11 g/l bioethanol. Scale up of optimised media to fermenter has resulted in a significant enhancement of bioethanol production to ⁓ 14.70 g/l.

Integrating bio-oil production from wood fuels to an existing heat and power plant - evaluation of energy and greenhouse gas performance in a Swedish case study

Combined heat and power (CHP) production in combination with a district heating (DH) grid gives an energy-efficient use of wood fuels. The heat demand in the DH grid will, however, decline in the coming decades, and operators are seeking additional heat sinks. In this case study, the integration of a pyrolysis unit into an existing CHP plant was investigated as a possible solution. The retrofitted pyrolysis unit makes use of excess heat and yields a liquid bio-oil. Pyrolysis integrated with CHP production was shown to give a net energy yield of at least 80%, and to decrease the net heat output to the DH grid. The carbon footprint of the delivered heat was very low at maximum 1.6 g CO2eq/MJ. Prolonging the operation of the pyrolysis unit to periods without heat delivery to the DH grid would increase the use of existing installations, but at the cost of energy yields decreasing to 63–70%. Up to 2.8 PJLHV/yr crude bio-oil could be produced at the investigated CHP plant. The bio-oil was shown to have a low carbon footprint, 1.7–4.0 g CO2eq/MJLHV, which makes it attractive for the rapidly expanding transport biofuel market.

Carbon sequestration and water yield tradeoffs following restoration of abandoned agricultural lands in Mediterranean mountains

Abandoned cropland areas have the potential to contribute to climate change mitigation through natural revegetation and afforestation programs. These programs increase above and belowground carbon sequestration by expanding forest cover. However, this potential to mitigate climate change often involves tradeoffs between carbon sequestration and water availability. Particularly in a water limited environments such as the Mediterranean region, any loss of recharge to groundwater or streamflow can have critical societal consequences. In this study, we used an ecohydrologic model, Regional Hydro-Ecological Simulation System (RHESSys), to quantify these tradeoffs for land management plans in abandoned cropland areas in Mediterranean mountains. Changes to Net Ecosystem Production (NEP), water yield and Water-Use Efficiency (WUE) under different land management and climate scenarios were estimated for Arnás, a catchment with similar geology, vegetation and climate to many of the locations targeted for land abandonment restoration in the Spanish Pyrenees. Results showed significant changes to both carbon and water fluxes related to land management, while changes related to a warming scenario were not significant. Afforestation scenarios showed the highest average annual carbon sequestration rates (112 g C·m−2·yr−1) but were also associated with the lowest water yield (runoff coefficient of 26%) and water use efficiency (1.4 g C·mm−1) compared to natural revegetation (−27 g C·m−2·yr−1, 50%, 1.7 g C·mm−1 respectively). Under both restoration scenarios, results showed that the catchment ecosystem is a carbon sink during mid-February to July, coinciding with peak monthly transpiration and WUE, while during the rest of the year the catchment ecosystem is a carbon source. These results contribute to understanding carbon and water tradeoffs in Mediterranean mountains and can help adapt restoration plans to address both carbon sequestration and water management objectives.

Total fusion yield measurements using deuterium–tritium gamma rays

The deuterium–tritium (DT) fusion reaction, D(T,γ)5He, has a rare (4.2 ×10−5) branching ratio that releases a ∼16 MeV gamma ray instead of the more common 14.1 MeV fusion neutron. These fusion gamma rays can be used as a complementary source of measuring the net fusion yield of experiments. Fusion gamma rays have the advantage of having negligible Doppler broadening, being isotropic and less down-scattered compared to fusion neutrons. At the National Ignition Facility, the DT fusion gamma rays are measured by the Gamma Reaction History diagnostic that thresholds to only measure >10 MeV gamma rays. After removing a ∼12% contribution from neutron capture interactions in deuterium, D(n,γ)T, and carbon, 12C(n,γ)13C, the deviation between GRH measurements and neutron-based yield measurements has been reduced to 10%. Further improvements are needed for detailed physics comparison.

Effect of the Surface Roughness of Tungsten on the Sputtering Yield under Helium Irradiation: A Molecular Dynamics Study

Sputtering in a divertor is one of the key phenomena that affects plasma purity and temperature. In previous experimental studies, the term sputtering yield has been used to refer to net sputtering yield, which is defined as the difference between primary sputtering yield and re-deposition. Our simulations using molecular dynamics have confirmed that both primary sputtering yield and re-deposition are affected by particle curvature. In this study, the effect of particle curvature on the net sputtering yield was quantitatively evaluated, the results were compared to existing experimental studies, and the discrepancies with experimental results were discussed.

Nutrient loading and farm characteristics of giant gourami fish aquaculture systems in Lake Maninjau, Indonesia: basic knowledge of production performance

Background Aquaculture systems for giant gourami, Osphronemus goramy Lacepède (1801), have significantly improved fish production yields and food security in Indonesia. However, these systems also cause serious problems in terms of eutrophication in waterbodies. This study analysed the nutrient loading and farm characteristics of giant gourami in floating cages in Lake Maninjau. Method A total of 20 floating cages were used to record these nutrients in feed supply, female and male juvenile fish, dead fish and harvested fish to estimate nutrient loading. Data on the harvested fish, production cycle, stock number and cage capacity were used to estimate the stocking density, feeding rate, feed efficiency, and net fish yield, and the relationship between feed supply and nutrient loading and farm characteristics was analysed by least squares regression methods. Results A total of 20 floating cages released nutrients into waterbodies at an average rate of 236.27±60.44 kg/cycle for C, 84.52±20.86 kg/cycle for N and 8.70±3.63 kg/cycle for P. On average, fish production for each floating cage (±SD) was 1226±282 kg wet weight/cycle, and the net fish yield was 12.63±2.82 kg/m3/cycle. Survival rates ranged from 86.33 to 95.27%/cycle. The production cycles varied from 160 to 175 days with feed conversion ratios between 1.60 and 1.75, feed conversion efficiencies were between 0.58 and 0.63. The production parameters that had strong relationships with the net fish yield were feed supply (r2=0.960), stocking rates (r2=0.924) and feeding rates (r2=0.961). In contrast, the length of the production cycle was not strongly related to the net fish yield (r2=0.187). Conclusion Nutrient loading from the supplied feed was greater than that from the harvested fish, juvenile fish and dead fish. Increasing the net fish yield in floating cages was better predicted by the stocking densities and feeding levels than by the other factors.

Analysis of Weather-Related Growth Differences in Winter Wheat in a Three-Year Field Trial in North-East Germany

Winter wheat is the most important crop in Germany, which is why a three-year field trial (2015–2017) investigated the effects of weather on biometric parameters in relation to the phenological growth stage of the winter wheat varieties Opal, Kerubino, Edgar. In Brandenburg, there have been frequent extreme weather events in the growth phases that are relevant to grain yields. Two winter wheat varieties were grown per trial year and parts of the experimental field areas were irrigated. In addition, soil physical, biometric and meteorological data were collected during the growing season (March until end of July). There were five dry periods in 2015, six in 2016, and two in 2017 associated with low soil moisture. Notably, in 2016 the plant height was 5 cm lower and the cover was 15% lower than on irrigated plots. The grain yield was increased by 19% and 31% respectively by irrigation. However, due to irrigation costs, the net grain yield on irrigated plots was lower than on the unirrigated plots. It turned out that in dry years there were hardly any differences between winter wheat varieties. Multiple regression analysis showed a strong correlation between the biometric parameters considered here and the grain yield.

Effects of artificial substrates on the growth and immunology of postlarvae of Marsupenaeus japonicus (Spence Bate, 1888) (Decapoda: Dendrobranchiata: Penaeidae) reared in biofloc

Abstract We investigated the effects of biofloc and artificial substrates (net and brush) on the growth and immunology of the postlarvae of Marsupenaeus japonicus (Spence Bate, 1888) reared for 30 days. The mRNA expressions of innate immune-related genes (prophenoloxidase, masquerade-like serine proteinase, and lysozyme) in the postlarvae were analyzed using quantitative reverse transcription PCR (qRT-PCR). The highest specific growth rate of larvae (3.66 ± 0.02% d–1, 3.75 ± 0.02% d–1) were shown in the net and control groups. The highest survival rate (90 ± 7.1%) was observed in the brush group (P < 0.05). The net yield was significantly higher in the artificial substrate groups (brush 36.60 ± 6.19 g m–2, net 36.46 ± 2.36 g m–2) than in the control (33.79 ± 0.16 g m–2) (P < 0.05). Total suspended, volatile suspended, and suspended solids were significantly lower in the brush group than in the other groups. The immune-related genes showed significantly higher expressions in the artificial substrate groups than in the control. These results support the benefits of artificial substrate in M. japonicus nursery culture to mitigate space competition and suppress cannibalism, with a positive effect on survival. The additional surface area provided by the biofloc, which the larvae can graze on, enhanced the expression of immune-related genes in individuals.

The Improvement of Maize (Zea mays L.) for Drought Stress Tolerance

Maize is one of the important cereals in the world after rice and wheat. It is grown for grain as well as fodder in tropical, sub-tropical and temperate regions of the World. The reduction of maize productivity under drought stress conditions depends on different factors such as plant development stage, drought intensity and duration of water deficit, and varietal sensitivity to drought stress. Drought stress is one of the major constraints to agriculture where limited water availability for crop irrigation causes a reduction in carbon fixation by the photosynthetic apparatus that result in net yield losses. Plant breeders desire novel and more accurate tools to fast-track breeding programs required for the increasing demands of food and fodder because farmers are facing a changing climate in which drought stress has major impacts on crop damages globally. Crop loss, because of drought stress, has a huge impact on agriculture industry and the economy. Therefore, to prevent economic loss and to make the crop plants more tolerant to drought stress, a variety of approaches such as conventional breeding and molecular/ genetic engineering are being practiced. Keywords: Genetic engineering, Conventional breeding, Molecular assisted selection, Drought and Stress DOI: 10.7176/JBAH/11-17-04 Publication date: September 30 th 2021

EFFECT OF REUSE BIOFLOC WATER ON GROWTH PERFORMANCE, FEED UTILIZATION OF NILE TILAPIA FINGERLINGS (OREOCHROMIS NILOTICUS)

Nile tilapia(Oreochromis niloticus) fingerlings (average weight and length: 20.20 ± 0.20 g, 10 ±0.25 cm)cultivated at reusing water from systems with biofloc technology (BFT) under three treatments: T1: Control, T2: tilapia cultured in reused water biofloc (RW) with adding carbohydrate and T3: tilapia cultured in reused water biofloc (RW) without adding carbohydrate. Nine rectangular tanks (66 x 47 x 44 cm, 75L) were used with stocking densities (400 Fish/m3) for 60 days to investigate fish growth performance, feed utilization, body composition, survival, water quality and also economic evaluation was done. Fish were fed a commercial diet containing 30% crude protein. Growth performance of tilapia was recorded biweekly. Water temperature, dissolved oxygen and pH, were recorded daily, while NO2–, NO3–N; total hardness, carbonate hardness and total suspended solids were recorded biweekly. The body composition of the whole fish was determined at the end of the experiment. Results showed that the best water quality parameters, finial body weight, weight gain, daily weight gain, specific growth rate, final biomass, net yield, PER, FCR, FE, feed intake and economic evaluation were significantly(P 0.05). The present study recommended rearing Nile tilapia in reusing water from systems with biofloc technology (BFT) without adding carbon source for best growth performance and prolonged the useful life, quality of water and reduced overall water consumption.

Shadow Insurance? Money Market Fund Investors and Bank Sponsorship

Investors in prime institutional money market funds paid higher expense ratios and received lower net yields as compensation for implicit bank guarantees and indirect access to the federal bank safety net.

Influence of tied-ridge with biochar amendment on runoff, sediment losses, and alfalfa yield in northwestern China

BackgroundLoss of organic matter and mineral nutrients to soil erosion in rain-fed agriculture is a serious problem globally, especially in China’s Loess Plateau. As a result, increasing rainwater usage efficiency by tied-ridge-furrow rainwater harvesting with biochar is expected to improve agricultural productivity. Nonetheless, with limited knowledge on tied-ridge-furrow rainwater harvesting with biochar, small-scale farmers face the challenge of adoption, thus, the rationale for this study.Materials and methodsA field experiment was conducted to determine the influence of open-ridging (OR) and tied-ridging (TR) with bio-degradable film on ridges and biochar in furrows on runoff, sediment losses, soil moisture, fodder yield, and water use efficiency (WUE) on sloped land, using flat planting (FP) without ridges and furrows as control, during alfalfa-growing year (2020).ResultsRunoff in flat planting (30%), open ridging (45%), and tied ridging (52%) were decreased with biochar to the extent where sediment was decreased in flat planting (33%), open ridging (43%), and tied ridging (44%) as well. The mean runoff efficiency was lower in flat planting (31%), open ridging (45%), and tied ridging (50%) in biochar plots compared to no-biochar plots. In biochar and no-biochar plots, soil temperature on ridges of TR was higher than that on OR, which was higher than FP during alfalfa growing season. Soil temperature in furrows during alfalfa growing season in biochar and no-biochar plots were in the order FP > OR > TR. Mean soil water storage for FP, OR, and TR, in biochar plots was higher than in no-biochar plots. This indicates biochar has a beneficial impact on open riding. Total annual net fodder yield (NFY) was significantly (p = 0.00) higher in treatments in the order TR > OR > FP. Tied ridging had a significant effect on actual fodder yield (AFY) in biochar plots, while open ridging significantly affected AFY in no-biochar plots. Annual total mean NFY and AFY increased by 8% and 11% in biochar plots compared to no-biochar plots. In biochar and no-biochar plots, water use efficiency was in the order TR > OR > FP. Conclusively, water use efficiency was significantly higher (p = 0.01) in biochar plots compared to no-biochar plots.ConclusionWhen crop production is threatened by soil erosion and drought, mulched tied-ridge with biochar is beneficial to crop growth in rain-fed agriculture, according to this research. Smallholder farmers should be trained on applying this technique for water-saving to mitigate runoff, soil erosion, sediment losses, and improve food security in semiarid areas.

Effect of enriched compost and crop establishment methods on productivity and profitability of rice (Oryza sativa)

A field experiment was conducted during kharif 2018-19 at ICAR-IARI, New Delhi to study the effect of rice (Oryza sativa L.) establishment methods and enriched organic nutrient sources on growth and productivity of rice. The experiment was laid out in split plot design with three replications having two main plot treatments, viz. aerobic rice (AR) and conventional transplanted (CT) rice and five sub plot treatments, viz. Control (No fertilizer), 100% RDF (100% mineral fertilization), 50% P through P enriched compost + 50% P through DAP, 50% N through N enriched compost + 50% N through urea and DAP and 100% organic (through N enriched compost and P enriched compost). Results showed that plant growth, productivity and profitability were significantly superior in CT rice than AR. Among the nutrient management options, 50% N through N enriched compost + 50% N through urea and DAP resulted in significantly higher grain yield (4.85 and 5.13 t/ha), gross (₹ 1.35 lakh and 1.43 lakh) and net return (₹ 85 lakh and 0.85 lakh) and yield attributes than other treatments and it was at par with 50% P through P enriched compost + 50% P through DAP in both the years. Hence, the conventional transplanting of rice along with integrated application of enriched compost and inorganic fertilizer may be recommended to farmers for getting higher productivity and profitability in rice.

Evaluating growth, production and economics of a new candidate species Labeo bata in cages: A regional model for table fish production in floodplain wetlands of North East India

Indian minor carp Labeo bata fingerlings were reared in square shaped cages at different numbers to evaluate the effect of stocking density on growth, production and economics. Fifteen cages (5 × 5 × 2 m each) were installed in deeper areas (6–8 m) of Samaguri beel (a seasonally-flooded floodplain wetland) of Assam, India. The cages were stocked with L.bata (mean length 11.93 ± 0.20 cm; mean weight 13.05 ± 0.77 g) at five different stocking densities of 10 (SD10), 20 (SD20), 30 (SD30), 40 (SD40) and 50 (SD50) fingerlings m−3 in triplicates. Fish were fed with floating pellets containing 32% CP at 3–5% body weight twice-a-day for six months. Density-dependent growth was evident from the results as growth of fish decreased with increasing stocking densities; the specific growth rate of the fish at SD10, SD20, SD30, SD40 and SD50 were 1.03 ± 0.02, 0.88 ± 0.01, 0.84 ± 0.02, 0.67 ± 0.02 and 0.52 ± 0.01 with corresponding weight gain percent of 533.3 ± 13.41, 385.8 ± 10.73, 353.3 ± 14.17, 232.2 ± 8.08 and 155.9 ± 5.38, respectively. However, the highest net yield of fish was achieved at SD30 (50.8 kg cage−1), which was significantly higher than other stocking densities. Also, economic analysis demonstrated highest benefit-cost (B:C) ratio at 30 fish m−3 (1.44). Results indicated decreased fish yield at lower densities though the individual growth rate of fish was higher. On the other hand, fingerling stocking more than 30 fish m−3 was uneconomical because of lower individual growth rate. Hence, a stocking density of 30 fish m−3 could be considered as optimum for production of L.bata table fish in cages. The study generated new and critical information on species diversification in cage aquaculture for tropical floodplain wetlands.

Life cycle assessment and cost-benefit analysis of internal-stack trickling bio-electrochemical reactor: an evaluation for commercial viability

ABSTRACT The present study reports a detailed life cycle assessment and cost–benefit analysis of a commercially viable Internal-Stack-Trickling Bio-Electrochemical Reactor (IS-TrickBER). IS-TrickBER used wastewater as a feedstock and converted that wastewater through electrochemical methods into low-grade fertilizer and produced electricity. IS-TrickBER was observed for its performance in terms of power output and wastewater treatment. IS-TrickBER exhibited up to 4.2 Wh net energy yield while treating 84.84L wastewater per day along with 92.17% COD removal and 38.23% Columbic efficiency during the operational run with real municipal wastewater. Based on daily net energy yield, up to 1457.6Wh yearly net energy yield can be expected. A comprehensive start-to-end life cycle assessment study associated with the manufacturing, and operational phases of IS-TrickBER was also conducted to ascertain its impact on the environment. The environmental impact through air emissions during the manufacturing stage can be minimized by changing the plastic balls used as packing material in the reactor. A detailed cost–benefit analysis was also conducted to understand its economic viability. Cost–benefit analysis of IS-TrickBER, based on net energy yield, shows that IS-TrickBER could compensate its installation cost within a few years. IS-TrickBER performed well in eliminating the chemical load of wastewater and simultaneous electricity generation. Due to its scalability, compactness, and low maintenance, IS-TrickBER can be a suitable candidate in real-time wastewater treatment.