Aquaponics

  • Aquaponics - for a sustainable future

    The challenges and potential of aquaponics production is still an unexplored area of study in  India. Aquaponics is a combined method of farming by bringing aquaculture and hydroponics together in a single system. There has been a positive change in Aquaponics farming as the popularity of the system increased in the last few years in our country.

    By 2050, the world’s population is estimated to increase to 9 billion. The expansive numbers of people are expecting to rely on agricultural sector including farming, fisheries, woodcrafts, and livestock. Natural calamities and crisis affect millions of people who depend on the primary sector. For reducing poverty and attaining food security, expansion of agriculture sector is the most efficacious means. Small farmers are the major contributors to the World’s food, but they are the poorest people in the developing countries. 70 per cent of the people living in the rural area depends on Agriculture even today, however, one-fourth of the population find it difficult to meets their daily nutritional requirement.

    Indian farmers are exposed to many challenges resulting from low agricultural growth, sustainability concerns, and land degradation, as a large area of farmland has become infertile due to the overuse of fertilizers and pesticides. Conventional farming methods because of large usage of fertilizers for growing crops degraded the quality of the soil and local water sources. It is high time to overcome these challenges through innovative farming methods. The technological and scientific advancement in the field of agriculture has opened a new era for the design and development of modern devices for plant health monitoring. Aquaponics farming is a solution to overcome some of these challenges to an extent if the farmers are able to maintain the system with proper care and technical support.

    Although aquaponics has received considerable attention in foreign countries, Indian farmers are relatively new to this system. However, there has been a gradual increase in awareness of this system over the past few years in the country.

    Aquaponics is an integrated method of growing fishes and crops in a re-circulating system. In other words, it is an integrated system of re-circulating aquaculture and hydroponics in one production system. Water from the fish tank that contains fish excretes cycles through grow beds where plants are grown, which is nutritious for the plant's growth and plants' filter the water flowing into the fish tank to keep the fish healthy. The main elements for aquaponics are the fish tank and grow beds with a small pump that filters water between the two. The success of an aquaponics system requires proper maintaining of the plants, fish, and nutrients that gives a well-balanced and interdependent relationship. Aquaponics farming is suitable for farmers who have fewer land holdings and in areas where water is scarce. Crops grown in aquaponics have less damage and are able to grow in denser climate.

    In India, the land holdings used for agriculture are limited to less than 0.2 hectares. As a result, the small-scale agriculturists aim to maximize production within the minimum resources. Growing awareness of consumers on the excessive use of fertilizers and pesticides are leading to a trend that favours organic farming. The interest of the young generation to produce vegetables and other regional cultivations on a small scale within the available land area has further boosted the scope of organic farming. Organic farming is a concept with considerable thrust on integrated systems wherein a major part of inputs required for farming is raised within the system. Integrated farming uses wastages and sub-products of a particular cultivation for the use of other. It usually includes growing and breeding of cattle, duck, fish etc. This is a globally accepted technology and adapted to a greater extent by the Indian farming community. Within the available space that includes terrace and balconies of apartments, Indian households have started taking up aquaculture in small tanks along with vegetables in separate grow beds. The method of recycling wastewater and making it available for further use has increased its demand all over this time. Integrating hydroponics (the method of growing plants without soil) and aquaculture has been given more importance in the current agricultural scenario.

    As the aquaponics system has many advantages and increases the productivity within a short time period, it has gained popularity in several states of India in recent times. State Fisheries Departments are promoting aquaponics by providing training programmes and technical support to the farmers. It is an effective means of growing food that helps to maintain sustainability, as it requires only 10 per cent of water and no use of chemical fertilizers as compared to the traditional farming method.

    Aquaponics as a commercial venture is evolving in India. People are discovering it as a promising avenue to rely upon as a dependable source of livelihood. Further, small and medium-sized units are more efficient in managing costs and realizing higher net income per unit area compared to large units. However, a variety of factors such as lack of training, inadequate technical guidance, ignorance of market pricing and uncertainties about the market demand of the product, are some of the reasons for incurring losses. These challenges can be overcome by providing technical sessions about the working of the system and by making consumers aware of the benefits of organic products. In Hydrilla workshops, apart from taking participants through Aquaponics farming methods, fish and plant health management, system design aspects, we take through the analysis of marketing strategies like identifying right crops based on market demand, direct selling to neighbourhood consumers, indirect selling to wholesalers, restaurants and grocery stores.

    In general, the success of aquaponics farming relies upon the local markets, climatic and geographical conditions. An important feature of aquaponics systems is their ability to reduce the local impacts that arise from the nutrient discharges. Due to the dynamic characteristics of the aquaculture industries, it is expanding rapidly in recent times. Hence, more emphasis should be given on high productivity, intensive systems with similar low global impacts rather than focusing completely on the reduction of local impacts.

    Aquaponics has immense potential to be the forerunner in the next phase of sustainable aquaculture.

  • Growing Peppers in Aquaponics

    Growing peppers in aquaponic units: There are many varieties of peppers, all varying in colour and degree of spice, yet from the sweet bell pepper to the hot chili peppers (jalapeno or cayenne peppers) they can all be grown with aquaponics. Peppers are more suited to the media bed method but they might also grow in 11 cm diameter NFT pipes if given extra physical support.

    Growing conditions: Peppers are a summer fruiting vegetable that prefers warm conditions and full sun exposure. Seed germination temperatures are high: 22–34 °C. Seeds will not germinate well in temperatures 30–35 °C lead to floral abortion or fallout. In general, spicier peppers can be obtained at higher temperatures. The top leaves of the plant protect the fruit hanging below from sun exposure. As with other fruiting plants, nitrate supports the initial vegetative growth (optimum range: 20–120 mg/litre) but higher concentrations of potassium and phosphorus are needed for flowering and fruiting. 

    Growing instructions: Transplant seedlings with 6–8 true leaves to the unit as soon as night temperatures settle above 10 °C. Support bushy, heavy-yielding plants with stakes or vertical strings hanging from iron wires pulled horizontally above the units. For red sweet peppers, leave the green fruits on the plants until they ripen and turn red. Pick the first few flowers that appear on the plant in order to encourage further plant growth. Reduce the number of flowers in the event of excessive fruit setting to favour the growing fruits to reach an adequate size. 

    Harvesting: Begin harvesting when peppers reach a marketable size. Leave peppers on the plants until they ripen fully by changing colour and improve their levels of vitamin C. Harvest continually through the season to favour blossoming, fruit setting and growth. Peppers can be easily stored fresh for 10 days at 10 °C with 90–95 per cent humidity or they can be dehydrated for long-term storage.

    pH: 5.5–6.5

    Plant spacing: 30–60 cm (3–4 plants/m2, or more for small-sized plant varieties)

    Germination time and temperature: 8–12 days; 22–30 °C (seeds will not germinate below 13 °C)

    Growth time: 60–95 days

    Temperature: 14–16 °C night time, 22–30 °C daytime

    Light exposure: full sun

    Plant height and width: 30–90 cm; 30–80 cm

    Recommended aquaponics method: media beds

    Reference: http://www.fao.org/3/a-i4021e.pdf

  • Catch the right fish!

    Aquaponics is an amazing way to garden. And workhorses of an aquaponic system are the aquaponic fish. Aquaponics is a natural process whereby fish are raised in an aquarium or large size fish tanks and their waste is pumped into grow beds. Waste is then naturally converted into nutrients for the plant’s roots to absorb within a grow medium. Plants, in turn, clean the water in this recirculating and symbiotic system.

    Before we can grow our plants, we must first choose the correct aquaponics fish. Not all aquaponic fish are equal or have the same requirements for survival. Therefore, let’s review some key considerations before choosing the best aquaponics fish for our needs.

    Considerations for choosing aquaponics fish: -

       Ornamental vs Edible: - While there are many aquaponics fish which do well in aquaponics systems, not all are edible. For example, goldfish and koi are great ornamental aquaponics fish – just don’t eat them! 

    Temperature: - 

    Some aquaponics fish thrive in cold water, while others do well only in warm water. Be sure we choose a species of fish that is hardy and adaptable for our particular indoor or outdoor conditions. Adding water heaters to

     

    the system is an option.

    Purchasing your Aquaponics fish: - Choose a species which is readily available to buy as a fingerling or juvenile fish. Selecting a suitable adult fish is also a possibility.

    Breeding: - If you want to produce your own stock, select a species that is capable of breeding within an enclosed aquaponics tank. However, understand the government regulations for the same.

    Popular Aquaponics Fish: -

    Here are the best aquaponics fishes, we have included an ideal temperature range for each species. Please note that while most fish are able to tolerate varying degrees of the temperature outside of the ideal range, we recommended you keep your aquaponics fish within these parameters as much as possible

    Tilapia: -

    • Tilapias are one of the most popular freshwater species to grow in aquaponic systems.
    • Why? For starters, tilapia is a great eating fish. It has a mild flavour, making it adaptable to many culinary styles. Tilapia is also a great fish for aquaponics beginners. They adapt to their environment and are able to withstand less than ideal water conditions. Other benefits of choosing tilapia include their fast growth rate (about 9 months from fingerling to harvest), ability to reproduce easily, and have an omnivorous diet.
    • One drawback to raising tilapia is the need to keep your aquaponics tank warm. Water below 55 degrees will cause tilapia to struggle. A constant water temperature of around 80 degrees is ideal. Adding a water heater is a viable option if water temperatures are fall low during winters, or you may consider choosing a different aquaponics fish altogether. Another possible drawback is their ability to breed quickly (every 4-6 weeks). If you have a small aquaponics system, be advised that it may quickly fill with young fish.

    Key Considerations: -

    1. Ideal Temperature Range: 72° – 86° F
    2. Popular, edible, warm-water aquaponics fish
    3. Easy to breeding and fast growing.

    Trout: -

    Looking for an aquaponics fish that thrives in cooler water? Trout may fit the bill. They thrive in temperatures ranging in the 50s and 60s. making them ideal for cool environments. This species of fish has a high food conversion ratio and grow quickly, although it may take up to 16 months to fully mature. In addition, trout are a desirable food source, loaded with protein and omega fatty acids.

    • Because trout thrive in cold water, some aquaponics enthusiasts alternate between raising tilapia during warmer months and trout during cooler months. Trout is also a popular aquaponics fish to raise in indoor garages and basements.
    • It should be noted that trout are not as adaptable as some other fish, as they require pristine water and high dissolved oxygen levels to thrive. Close monitoring of ‘PH’ levels is also important. Another possible downside is fewer plants choices. Because recirculating cold water may harm certain plants, be sure to pick hardier plants varieties. With that said raising trout may be too much effort for some, but the payoff at the dinner table makes this species a popular aquaponics fish.

    Key Considerations: -

    • Ideal Temperature Range:   56° – 68° F
    • Edible cold-water fish
    • Requires pristine water, high dissolved oxygen levels, and close pH monitoring

     Catfish: -                       

    • Catfish are a popular bottom-feeding aquaponics fish. They vary in size and are often commercially farmed for their flavour and high vitamin D content. Another advantage to choosing catfish is their high food conversion ratio, meaning they convert their food to body mass quickly.
    • Raising catfish requires close monitoring of the aquaponics system. Water must remain pristine, temperatures must remain close to 80 degrees, and PH should be kept in check. Catfish feed on a variety of plants, bugs small fish, and pellets. They do not have scales, so skinning is required before putting catfish on the frypan.

    Key considerations: -

    • Ideal Temperature Range:   78° – 86° F
    • Edible, popular aquaponics fish
    • High food conversion ratio makes them a fast-growing fish
    • Sensitive to water temperature, water quality, and pH

    Perch: -

     Silver, Yellow, and Jade varieties of perch are popular aquaponics fish. Because they are adaptable to various conditions, perch make a good starter fish for beginners. Perch typically thrive in water temperatures ranging in the 70’s. However, they are able to withstand colder water down to the 50’s.

    • The diet of perch is primarily carnivorous, consisting of small fish, bugs, and shrimp. This may turn some off to raising perch because carnivorous diets involve more expense and effort (compared to fish who simply consume pellets and plant matter). Another factor to consider is the longer time frame to mature. Silver perch, for example, may take up to 16 months to fully mature from the fingerling stage.  Overall, perch are a good choice for those looking for a tasty aquaponics fish and have the patience to wait for them to develop…and the budget to feed them their preferred diet.

    Key considerations: -

    • Ideal Temperature Range:   70° – 82° F
    • Edible, hardy, adaptable aquaponics fish
    • Slower to mature and carnivorous diet

     Barramundi: -                                       

    • Barramundi is one of the most popular fish raised in aquaculture. They also make a great aquaponics fish and can be kept in both fresh and saltwater systems. As an edible aquaponics fish, barramundi has flaky white flesh and are regarded as a good species for eating.
    • Larger barramundi is known to attack smaller ones, so it is advised to keep these fish separated by size or risk young being injured or eaten. Many aquaponics hobbyists purchase larger juvenile fish instead of fingerlings. This cuts down the likelihood of losing fish to aggression. Barramundi also requires pristine water conditions and high dissolved oxygen levels.

    Key considerations: -

    • Ideal Temperature Range:   78° – 83° F
    • Edible aquaponics fish, popular in commercial aquaculture
    • High food conversion ratio
    • Aggressive tendencies towards smaller fish

    Bass: -

    • Largemouth, smallmouth, and striped bass are another top aquaponics fish. However, this species is less adaptable to unfavourable conditions compared to others. Conditions must be monitored to ensure pristine water, and proper oxygen and PH levels. In addition, bass will not tolerate bright light or a poor feeding regime. Another downside is the long wait period to mature. Largemouth bass can take up to 18 months to reach its full size. Striped bass typically mature faster.
    • The upside to using bass as young aquaponics fish is that they are edible and fairly easy to acquire locally. Young fingerings can be trained to feed on pellet food but are generally carnivorous.
    • If you don’t mind the daily monitoring of your aquaponics system, bass is a viable and rewarding aquaponics fish.

    Key considerations: -

    • Ideal Temperature Range:   75° – 85° F
    • Edible and accessible aquaponics fish
    • Requires constant monitoring to ensure proper conditions

    Koi Fish: -

    • One of the most popular ornamental fish is Koi. They are often found in decorative ponds. Like goldfish, koi produce a lot of waste matter and are easy to find at pet stores. This makes koi a popular aquaponics fish.
    • Koi are prized for their beauty and bright coloration. Surprisingly, koi are considered an edible aquaponics fish. However, we don’t recommend eating them. Most hobbyist raise koi strictly for ornamental purpose.
    • Other advantage of koi includes their resistance to parasites, long life-span, and their simple omnivorous diet. A key disadvantage is the cost to purchase koi. While they are fairly easy to find at pet stores, koi tend to be more expensive than most aquaponics fish. Koi can live up to an astounding 40-60 year.

    Key considerations: -

    • Ideal Temperature Range:   65° – 75° F
    • Ornamental, not typically eaten
    • Ornamental, hardy, and attractive aquaponics fish
    • Omnivorous, parasite-resistant, and lives a long time

     Gold Fish: -                                       

    • Goldfish are one of the earliest species of the fish to be domesticated and among the most popular fish used in aquaponics today. They are attractive in appearance and are readily available at local pet shops. Generally speaking, these miniaturized carp species are hardy and adaptable to various water conditions.
    • They prefer a temperature in the 60s-70s degree range. Goldfish are especially well-suited for smaller aquaponics systems but can thrive in an aquaponics system of any size.
    • Goldfish are known as a shy fish, Because of this quirkiness, they require plant cover to breed. For such a small species, goldfish produce lots of beneficial waste nutrients for aquaponics grow beds to absorb. Due to this small size and susceptibility to parasitic issues, goldfish are not considered edible fish.

    Key considerations: -

    • Ideal Temperature Range:   68° – 75° F
    • Ornamental, not typically eaten
    • Small, hardy aquaponics fish
    • Produces lots of waste despite its size
  • Understanding PH Control

    What is pH?

    pH is a measure of the relative concentration of hydrogen ions (H+) to hydroxide ions (OH-). The greater the number of H+ ions in relation to OH- the more acidic the solution becomes. The greater the ratio of OH- ions to H+, the more basic the solution becomes. PH is measured on a scale of 1-14. A reading below 7 means that there are more H+ ions and a reading above 7 indicates more OH- ions. At pH 7 there are the same number of H+ ions as OH- ions so the pH is neutral, neither acid nor base.

     

     

     

     

     

     

     

     

     

    Acids and Bases

    Any substance that increases the concentration of hydrogen ions (lowers the pH) when added to water is called an acid. A substance that reduces the concentration of hydrogen ions (raises the pH) when added to water is called a base or an alkali. Some substances enable solutions to resist pH changes when an acid or base is added. These substances are called buffers. Buffers are very important in helping to maintain a relatively constant pH in a feeding solution and in the root zone after the water has been applied to the crop. Most greenhouse water supplies have sufficient alkalinity that they require routine acid addition to correct the pH to the normal 5.8-6.2 feeding range. At this level, the irrigation water tends to have a neutral effect on media pH, although this depends on the buffering capacity of the media. Some growers use very pure water from rain and surface sources. In these situations, they may need to apply a combination of acid and base materials to stabilize and buffer the pH.

    Why does pH Matter?

    Improper management of media pH can result in poor growth and reduced plant quality in greenhouses and nurseries. The pH or soil reaction has a primary influence on the solubility and availability of plant nutrients. Many crops have a narrow range of pH tolerance. If the pH of the soil medium falls above or below this tolerance zone, they may not grow properly due to nutrient deficiency or toxicity.

    The availability of most fertilizer elements is affected to some extent by the media pH. Calcium and magnesium become more available as the pH increases, while iron, manganese, and phosphorus become less available. A one-unit pH drop can increase the solubility of manganese by as much as 100 times, and the solubility of iron by as much as 1000 times.

    Why Adjust Irrigation pH?

    By carefully modifying the pH and alkalinity of your irrigation and feed solutions, you can help maintain the desired plant growth and quality. There are other reasons to monitor and control pH in your irrigation water and nutrient solutions: 1) Solution pH affects the availability of nutrients. 2) Correct pH helps ensure dissolved fertilizer concentrates remain in solution when mixed in the water supply. 3) Acid injection can be used to neutralize excess alkalinity in water supplies.

    Understanding The pH Scale

    The pH scale measures the relative concentration of Hydrogen Ions (H+) and Hydroxyl ions (OH-) in a solution. Technically, the pH of a solution is defined as a negative logarithm of the hydrogen ion concentration. The ‘p’ is the mathematical symbol for a negative logarithm and the ‘H’ is the symbol for hydrogen. The pH scale measures this, and places a value on it ranging from 0 to 14. Since it is a log scale, each number on the scale is 10 times greater (or smaller) than the next. A lower pH number corresponds to a higher concentration of hydrogen ions (H+) relative to hydroxyl ions (OH-). A higher pH number corresponds to a relatively lower concentration of hydrogen ions

    Measuring pH

    There are several methods available for measuring pH, but the most useful and practical is an accurate pH meter. Follow the instructions included to preserve the accuracy and life of your instrument. These meters typically use a liquid filled glass probe, although some are now using flat sensor technology.

    Water and nutrient solution samples can be measured directly or preferably after a few hours of settling time. Dissolved CO2 in water supplies can cause slightly lower readings until the sample has come to equilibrium with the air. When testing media, freshly mixed samples of media should be watered and allowed to stand for 24 hours before a reading is taken to release some of the lime and fertilizers. The preferred method for testing media pH is to obtain several representative samples of a crop and to measure each separately. Multiple measurements give greater accuracy in reading, and shows the degree of variability of pH across several locations. A saturated media extract or a 1:1 soil to distilled water ratio is fine for measuring media pH.

    Factors Affecting pH

    These variables can affect the final pH, the rate of pH change, and the amount of modifying action required. They include the effects of:

    • Soil temperature
    • Fertilizer materials (may raise, lower or buffer pH)
    • Soil amendments such as gypsum, sulfur and lime
    • Root volume & metabolic activity
    • Soil microorganisms
    • pH and alkalinity of the irrigation water
    • Leaching fraction
    • Buffering capacity of both the soil medium and the irrigation source
    • Media cation exchange capacity
  • Know your water

    Know your water to know your best water soluble fertilizer options.

    Water quality is the single most important factor in determining solubility and nutrient availability for plants. It’s especially important that you test for the key parameters like pH, TDS and EC if you have one of the following factors:

    • Borewell water
    • Change in irrigation water source
    • Multiple sources of irrigation water
    • Recent flooding or droughts

    The primary considerations when formulating and evaluating your plant nutrition program are:

    1. Nutritional content of the water
    2. Its effect on growing media pH
    3. Its content of potentially toxic components

    With today’s soilless growing media, water’s alkalinity is the main area of focus. Alkalinity is a measure of how much buffering the water will provide to the given growing media.
    If alkalinity is too low, the growing media pH can plunge due to acidic influences like fertilizer, growing media components and plant root exudates. If this happens micronutrient toxicities can occur. Conversely, if alkalinity is too high, growing media pH can soar, leading to deficiencies in micronutrients, such as iron. In this case, you may be applying plenty of iron, but it becomes unavailable to the plant at higher growing media pH.
    A thorough water analysis will measure the alkalinity of your irrigation water as well as many other elements. Having your water tested can make the difference between growing a good crop and growing a great crop!

    The four main water types:

    While it’s important to get complete water analysis of your irrigation supply, you can base your fertilizer choices on your water type category and the plants you’re growing.

  • Food Security & Sustainable Farming methods

    The increase in population and urbanization has resulted in increased need for food and water in India. Our lands have become water and nutrient scarce and continuous use of synthetic fertilisers has depleted soil diversity which is needed for crop production. Challenges such as soil-borne diseases, weeds, and soil infertility, associated with soil plant production have made the soil culture risky and at times undesirable. As a result of the need to produce more and good quality food, without further damage to the natural environment, there has been an exploration of soilless agricultural systems, most popular, these include aquaculture, hydroponic and recently aquaponics system.

    Overview of Soilless Systems

    In soilless production, plants are raised without using soil as a growth medium. The method of not using soil as a crop stand saves significant water because in soil systems water can leach into groundwater. There are various common and available soilless productions systems; these systems include hydroponic, aeroponics, aquaponics, vertical gardens and tunnel or greenhouse aquaculture culture. Soilless production plays a critical and unique role in providing out of season food (meat and crop plants), herbs and flowers. While soilless systems have been a viable option to food and nutrition security in many countries there is little known or documented about these systems.

    Hydroponics 

    Hydroponics or hydroponic culture is a system where plants are grown in a soilless growth medium where all mineral nutrients delivered to plants are first dissolved in water before nutrients are available to plants. There are two types of hydroponic systems that are usually in use, these are liquid and aggregate production systems. The liquid hydroponic culture usually adopts nutrient film technique, and Deep-Water Culture (DWC)/floating rafts system. The growth medium hydroponic systems adopt various inert materials such as gravel, perlite, peat moss, peat, sawdust, rock wool, coconut fibre, grow stones, oasis cubes, vermiculite, coarse sand and expanded clay pellets.

    Aquaponics

    Aquaponics is a bio-integrated system that links recirculating aquaculture with hydroponic vegetable, flower, herb production, in the process saving a significant quantity of water. In an aquaponics system, effluent that is generated from the fish tanks is pumped and used in fertigation of growth medium beds (GMB) in hydroponic culture. In return, this process is worthy to the fish, because crop plants roots system together with rhizobacteria helps to extract available nutrients from water solution. The nutrients materials produced from fish algae, manure, and decomposing uneaten fish feed are pollutants that could build up to lethal levels in fish tanks, however, this instead waste serve as liquid mineral fertilizer in hydroponic culture. The hydroponic culture function as a biofilter removing off ammonia, nitrates, nitrites, and phosphorus and other trace elements, so the freshly cleansed water can then be recirculated back into the fish tanks. The nitrifying bacteria living in the gravel and in association with the plant roots play a crucial role in nutrient cycling. In the absence of these microorganisms, the whole system would be dysfunctional.

    Role of Hydroponics & Aquaponics in Food Security

    Food security exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life. There are four food security pillars which define, defend and measure food security status locally, nationally and internationally. These are food availability, food accessibility, food utilization and food stability.

    On top of food and nutrition security agenda/resolution is to achieve a method or programme that can directly support people with the opportunity to realize food security, particularly nutrition security. Developing simplified Hydroponics systems to make nutritious food production achievable for one and all is the core mission of Hydrilla Urban farms.

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