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Nutrient Management in Fish culture with emphasis on soil health and carbon budget management
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... The best method for preventing soils and other associated water quality problems in aquaculture ponds is to select a site with good soils and adequate supply of high quality water and to maintain moderate levels of prawn and fish production. If this is done, liming, fertilization and aeration can prevent most soil and water quality imbalances [11]. Fertilization will continue to be an important management practice in aquaculture for the foreseeable future [12]. ...
... The liming of fish ponds using same kinds and dosage of lime before fertilization process showed the same pattern of increasing of pH value. According to [11] sediment containing calcium carbonate in had pH values between 6.9 and 8.1. The best pH for pond soils is considered to be 6.5 to 7.5, and pH 5.5 to 8.5 is considered acceptable [16]. ...
... The water passing over acid soil tends to be acidic with low alkalinity and hardness. Acid ponds do not respond well to fertilization [11]. Water pH after liming and fertilizing at incubation periods increased until optimal for fish culture ( Figure 2). ...
Swamp fish pond has a problems related to submerged flat soil and water pH value and result in low productivity of ponds. Fertilization increase productivity of pond water by providing nutrients for fish food organisms, The objective of this research was to determine the best dosage of organic fertilizer to improve water quality and pond productivity and it’s effect to survival and absolute growth of catfish Pangasius sp. The research was conducted with using completely randomized design with four treatments and three replications. All of ponds unit were limed using dolomite of 10 ton/ha, incubated for 13 days, then gave four difference dosage of organic fertilizer, that were without fertilizer (P0), with fertilizer of 100 g/m ² (P1), 170 g/m ² (P2), and 240 g/m ² (P3). Pangasius sp. fish (average body length of 5±0.5 cm) was stocked with the density of 15 fish/m ² and cultured for 30 days. The parameters observed were soil (pH, N, P2O5, Ca, and C-organic) and water quality (pH, alkalinity, temperature, dissolved oxygen, ammonia, total Phosphate, Ca, and TOC), pond productivity, density of phytoplankton, survival, absolute growth, feed efficiency, and production of fish. The data were statistically analyzed by one-way ANOVA, Least Significant Difference test, and regression models analysis. The results showed that P1 (100 g/m ² of fertilizer) was the best dosage indicated by pH 7.60, nitrogen 0.13%, P2O5 0.16%, Ca 2.59%, C-organic 1.49% of pond soil; pH 7.42, temperature 27.3-32.4°C, dissolved oxygen 4.94-5.09 mgL ⁻¹ , alkalinity 51.33 mgL ⁻¹ , Ca 55 mgL ⁻¹ ,TOC 12.3 mgL ⁻¹ , ammonia 0.24 mgL ⁻¹ , Total Nitrogen (TN) 3.78 mgL ⁻¹ , Total Phosphate (TP) 0.109 mgL ⁻¹ of pond water. Based on TN:TP (10.09) of water showed nutrient was balanced. Productivity of ponds was on eutrophic state based on both TN and TP. Survival rate of catfish was 100%, absolute gain of weight 8.46 g and lenght 3.99 cm, Feed efficiency of fish was 101.55% and the density of phytoplankton was 217 cell/mL.
... Soluble phosphate of above 0.20mg/l may be indicative of medium to high and highly productive fish ponds (Adhikari et al., 2017). Based on available-P, soil could be classified as low (<30ppm), medium (30-60ppm) and high (>60ppm). ...
Background: Phosphatase producing bacteria (PPB) plays a major role in mineralising organic P into inorganic form. Though application of bacterial biofertilizers are practiced in agriculture, their application is very limited in aquaculture. Method: The PPB isolates were screened and isolated from rhizospheric sediment of mangrove, Avicennia marina of Ennore creek, Tamil Nadu. Their P transformation potential and the possibilities of their application in aquaculture to mineralise organic P to inorganic P were studied. Result: Twenty PPB isolates were screened in the study site and their Alkaline Phosphatase (ALP) activity was in the range of 13.6-20.4 µmol.ml-1.hr-1. Out of this, five Bacillus sp isolates were selected to assess their P transformation potential at various salinity. The P mobilizing potential of these isolates were compared with the commercial PPB following a microcosm study for a period of 14 days. During the study period, there is a significant increase in phosphorus in water as well as ALP activity and available phosphorus concentrations in sediments were observed between control and treatment tanks. Among the treatment groups, B. subtilis treatment tanks showed maximum P in water ie. 1.60mg.L-1, followed by B. altitudinis –1.49mg.L-1; B. pumilus –1.47mg.L-1; the soil ALP activity was in the order of commercial P products greater than B. pumilus greater than B. subtilis greater than B. paramycoides greater than B. altitudinis greater than B. aryabhattai. In terms of available phosphorus content in sediments on 14th day, there is no significant difference observed between B. pumilus and commercial product with respect to available P content of sediment.
... mg/l ( Table 1). All of these components were found to be suitable and productive for the fish culture pond, as suggested by Adhikari et al. (2017) that the level of phosphorus between 0.05 to 0.20 mg/l, and above 0.20 mg/l, may be indicative of medium to high, and highly productive fish ponds respectively. The values of nitrogen and potassium were found to be suitable and well supported by Ayyappan (2013). ...
The present study was conducted to optimize the stocking density for pond fish culture. For this purpose, two different stoking densities, i.e. 18000 (T1) and 7600 per hectare (T2) were tested using earthen ponds of 0.25 ha size. Both ponds were stocked uniformly with 4 carp species, viz. Catla catla, Labeo rohita, Cirrhinus mrigala, and Cyprinus carpio in equal proportions and fed on commercial pellet feed (20% crude protein). The estimated gross production was found higher in pond T2 (4166 kg/ha) than that of T1 (4000 kg/ha). The T2 pond showed a net estimated additional yield of 187.76 kg/ha, which was 4.74% higher than that of T1 pond. A higher survival rate was observed in T2 (59.17%) than that of T1 (27.68%), which was statically significant. Further, the ADG (average daily growth) rate of fishes in T2 was 0.70 kg/ha/day higher than that of T1. The study revealed that there is an inverse relation between the stocking density of fishes and production rate. Considering the growth/production rate and survival in present study, a seed stocking density of 7600 per ha is recommended for farm pond aquaculture.
With a large land area and diverse ecoregions, there is a considerable potential of terrestrial/soil carbon sequestration in India. Of the total land area of 329 million hectares (Mha), 297 Mha is the land area comprising 162 Mha of arable land, 69 Mha of forest and woodland, 11 Mha of permanent pasture, 8 Mha of permanent crops and 58 Mha is other land uses. Thesoil organic carbon (SOC) pool is estimated at 21 Pg (petagram = Pg = 1 1015 g= billion ton) to 30-cm depth and 63 Pg to 150-cm depth. The soil inorganic carbon (SIC) pool is estimated at 196 Pg to 1-m depth. The SOC concentration in most cultivated soils is less than 5 g/kg compared with 15 to 20 g/kg in uncultivated soils. Low SOC concentration is attributed to plowing, removal of crop residue and other biosolids, and mining of soil fertility. Accelerated soil erosion by water leads to emission of 6 Tg C/y. Important strategies of soil C sequestration include restoration of degraded soils, and adoption of recommended management practices (RMPs) of agricultural and forestry soils. Potential of soil C sequestration in India is estimated at 7 to 10 Tg C/y for restoration of degraded soils and ecosystems, 5 to 7 Tg C/y for erosion control, 6 to 7 Tg C/y for adoption of RMPs on agricultural soils, and 22 to 26 Tg C/y for secondary carbonates. Thus, total potential of soil C sequestration is 39 to 49 (44 5) Tg C/y.
Most sources of stress in aquaculture, fish salvage, stocking programs, and commercial and sport fisheries may be unavoidable.
Collecting, handling, sorting, holding, and transporting are routine practices that can have significant effects on fish physiology
and survival. Nevertheless, an understanding of the stressors affecting fish holding can lead to practices that reduce stress
and its detrimental effects. The stress-related effects of short-term holding are influenced by water quality, confinement
density, holding container design, and agonistic and predation-associated behaviors. Physiological demands (e.g., resulting
from confinement-related stresses) exceeding a threshold level where the fish can no longer compensate may lead to debilitating
effects. These effects can be manifested as suppressed immune systems; decreased growth, swimming performance, or reproductive
capacity; even death. Furthermore, holding tolerance may depend upon the species, life stage, previous exposure to stress,
and behavior of the held fish. Water quality is one of the most important contributors to fish health and stress level. Fish
may be able to tolerate adverse water quality conditions; however, when combined with other stressors, fish may be quickly
overcome by the resulting physiological challenges. Temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, pH,
carbon dioxide, alkalinity, and hardness are the most common water quality parameters affecting physiological stress. Secondly,
high fish densities in holding containers are the most common problem throughout aquaculture facilities, live-fish transfers,
and fish salvage operations. Furthermore, the holding container design may also compromise the survival and immune function
by affecting water quality, density and confinement, and aggressive interactions. Lastly, fishes held for relatively short
durations are also influenced by negative interactions, associated with intraspecific and interspecific competition, cannibalism,
predation, and determining nascent hierarchies. These interactions can be lethal (i.e., predation) or may act as a vector
for pathogens to enter (i.e., bites and wounds). Predation may be a significant source of mortality for fisheries practices
that do not sort by size or species while holding. Stress associated with short-term holding of fishes can have negative effects
on overall health and well-being. These four aspects are major factors contributing to the physiology, behavior, and survival
of fishes held for a relatively short time period.
In intensive aquaculture systems, ammonia–nitrogen buildup from the metabolism of feed is usually the second limiting factor to increase production levels after dissolved oxygen. The three nitrogen conversion pathways traditionally used for the removal of ammonia–nitrogen in aquaculture systems are photoautotrophic removal by algae, autotrophic bacterial conversion of ammonia–nitrogen to nitrate–nitrogen, and heterotrophic bacterial conversion of ammonia–nitrogen directly to microbial biomass. Traditionally, pond aquaculture has used photoautotrophic algae based systems to control inorganic nitrogen buildup. Currently, the primary strategy in intensive recirculating production systems for controlling ammonia–nitrogen is using large fixed-cell bioreactors. This option utilizes chemosynthetic autotrophic bacteria, Ammonia Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB), for the nitrification of ammonia–nitrogen to nitrite–nitrogen and finally to nitrate–nitrogen. In the past several years, zero-exchange management systems have been developed that are based on heterotrophic bacteria and have been promoted for the intensive production of marine shrimp. In this third pathway, heterotrophic bacterial growth is stimulated through the addition of organic carbonaceous substrate. At high carbon to nitrogen (C/N) feed ratios, heterotrophic bacteria will assimilate ammonia–nitrogen directly into cellular protein. This paper reviews these three ammonia removal pathways, develops a set of stoichiometric balanced relationships using half-reaction relationships, and discusses their impact on water quality. In addition, microbial growth fundamentals are used to characterize production of volatile and total suspended solids for autotrophic and heterotrophic systems.
The present study was conducted to determine the carbon (C) footprint of different aquaculture production systems in India. The total input (kg CE/ha) in different cultures, respectively, was 1,811 to 4,144 for scampi, 4,417 to 5,913 for polyculture, 4,090 to 8,873 for shrimp and 2,417 to 2,786 for carp. Of the total inputs, feed accounts for around 90% of carbon equivalent (CE), in all cultures. The output in different cultures, expressed on live weight basis (kg/ha) and on input basis (kg/kg), respectively, was 1,280 to 3,288 and 0.71 to 0.79 for scampi culture, 4,639 to 5,998 and 1.00 to 1.05 for polyculture, 2,130 to 5,436 and 0.52 to 0.61 for shrimp culture, 4,100 to 4,160 and 1.49 to 1.70 for carp culture. On the basis of output: input ratio, the carp (three species of Indian major carp) culture is more sustainable followed by polyculture (carp with scampi), scampi and shrimp culture, respectively.
During the past decade, pond aeration systems have been developed which will sustain large quantities of fish and invertebrate biomass. These aeration systems are modifications of standard wastewater aeration equipment. Aeration-performance testing has been important in selecting design features to provide cost-effective yet efficient aquaculture pond aerators. Paddlewheel aerators and propeller-aspirator-pumps are probably most widely used. Amounts of aeration vary from as little as 1–2 kW ha−1 in some types of fish culture to as much as 15 or 20 kW ha−1 in intensive culture of marine shrimp. Calculations suggest that about 500 kg additional production of fish or crustaceans can be achieved per kW of aeration. Aerators usually are positioned in ponds to provide maximum water circulation. This practice can result in erosion of pond bottoms and inside slopes of embankments, and accumulation of sediment piles in central areas of ponds where water currents are weaker. Recent studies suggest that the use of heavy aeration to provide the greatest possible production is less profitable than moderate aeration to improve water quality and enhance feed conversion efficiency. Automatic devices to start and stop aerators in response to daily changes in dissolved oxygen (DO) concentrations are improving, but they are expensive and not completely reliable. Augmentation of natural supplies of DO in ponds often is necessary to prevent stress or mortality of fish and crustaceans when DO concentrations are low. Several procedures have been used in attempts to increase DO concentrations in ponds. These methods include exchanging part of the oxygen-depleted pond water with oxygenated water from a well, pond, or other source, application of fertilizer to stimulate oxygen production by photosynthesis of aquatic plants, additions of compounds which release oxygen through chemical reactions, release of pure oxygen gas into pond waters, and aeration with mechanical devices which either splash water into the air or release bubbles of air into the water. Water circulation devices also enhance DO supplies in ponds by mixing DO supersaturated surface waters with deeper waters of lower DO concentration. This reduces the loss of oxygen from ponds by diffusion. Also, when surface waters are not saturated with DO, water circulation causes surface disturbance and enhances oxygen absorption by the water. Mechanical aeration is by far the most common and usually the most effective means of increasing DO concentrations in ponds. In semi-intensive aquaculture, aeration is applied on an emergency basis. Farmers check DO concentrations, and when low concentrations of DO are expected, aeration is applied. In intensive aquaculture, aeration is applied each night or even continuously. The purpose of this article is to summarize the ‘state of the art’ of mechanical aeration of aquaculture ponds.
Adequate food supplies and a reasonable quality of life require energy-both in commercial and non-commercial forms. This book presents an overview of energy for agriculture. The purpose is to put energy for agriculture in perspective by presenting numerous national and regional examples of energy usage. Since the early 1970s, world petroleum prices have fluctuated from US$3/barrel to more than US$40/barrel in 1981, and then back to one-third of the peak price today. Consequently, the rural sector depends heavily on non-commercial energy sources. Availability of such energy is highly site-specific. The book deals extensively with non-commercial energy - its sources, the technologies for converting energy to more useful gaseous and liquid forms, and its ultimate end-uses.
The influence of the microbial activity on the strength of activated sludge flocs was studied in short term experiments (0–3 h). Increased floc strength was generally obtained when the aerobic microbial activity was stimulated by adding substrate. Deflocculation was observed when the aerobic microbial activity was inhibited by (i) anaerobic conditions; (ii) addition of the metabolic inhibitors azide and chloramphenicol; and (iii) reduction of the temperature to 4°C. Furthermore, addition of nitrate as electron acceptor under anaerobic conditions partly prevented deflocculation from taking place. These results strongly suggested that microorganisms using oxygen and/or nitrate as electron acceptors were important for maintaining the floc strength. The increase in turbidity under deflocculation was well correlated with the number of bacteria and concentration of protein, humic substances and carbohydrates in the supernatant. However, only approximately 1–2% of the total amount of sludge deflocculated, so the deflocculation could be understood as an erosion of small particles from the larger flocs. The extent of deflocculation under anaerobic conditions could be enhanced by stimulation of the anaerobic biological activity. When anaerobic conditions prevailed, a microbial iron reduction immediately started with iron reduction rates of 4–150 μmol/gVS·h. Subsequently, a decrease in floc strength was observed which could also be observed when the iron-reducing bacterium Shewanella alga BrY was added to the activated sludge. Furthermore, the importance of Fe(III) for the floc strength was illustrated by removal of Fe(III) from the sludge matrix by adding sulphide, which resulted in strong deflocculation. Thus, the deflocculation observed could be either directly due to lack of aerobic microbial activity or indirectly due to change in the local physico-chemical conditions mediated by anaerobic microbial activity.