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--- introduction [2023/06/09 19:45] – baz
+++ introduction [2023/06/18 16:45] (current) – old revision restored (2023/06/12 18:59) baz
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 iAVs, or integrated Aqua-Vegeculture System, is a method of agriculture that was developed to address the challenges of food production in arid and underdeveloped regions like the African Sahel. It is a low-cost, low-tech system that combines aquaculture and horticulture in a closed-loop system, allowing for the production of fresh fish and vegetables in a small space. The goal of iAVs is to provide a sustainable source of food and nutrition for communities in need.
-To successfully operate an iAVS system, one needs to have a basic understanding of horticulture, aquaculture, and hydroponics. Knowledge of plant physiology, soil science, pest management, and water quality management is essential. Experience in managing fish tanks and growing plants is also helpful.
+To successfully operate an iAVS system, one needs to have a basic understanding of horticulture and aquaculture. Knowledge of plant physiology, soil science, pest management, and water quality management is essential. Experience in managing hydroponics, fish tanks and growing plants is also helpful.
 In terms of equipment, an iAVS system requires a fish tank or tanks, sand beds for growing plants, and a pump to circulate water between the fish tank and sand beds. The sand bed serves as both the mechanical filter and biological filter, eliminating the need for additional filtration equipment.
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 Overall, operating an iAVS system requires knowledge of horticulture, aquaculture, and hydroponics; experience in managing fish tanks and growing plants; equipment such as fish tanks, sand beds, pumps; aeration equipment (if needed); regular monitoring and maintenance to ensure optimal plant growth and fish health.
+===== Why Sand? =====
+Sand is used in iAVS systems because of its unique properties that make it an ideal growing medium and bio-filter.
+The coarseness of the sand creates large pore spaces that allow for fast drainage and a vacuum effect, which replaces the oxygen around the roots of plants. This promotes healthy root growth and allows for efficient nutrient uptake. In addition, sand develops a biofilm over time that stores water and nutrients while providing food and homes for beneficial microbes.
+This biofilm helps to maintain a healthy balance of microorganisms in the system, which is essential for optimal plant growth and water filtration.
+Sand has been used for centuries as a water filtration device due to its ability to remove impurities from water. The ancient Egyptians were known to use sand filters to purify their drinking water, and sand filtration has been used in municipal water treatment plants since the early 1800s.
+Today, sand remains one of the most effective and widely used filter media due to its low cost, durability, and effectiveness at removing contaminants from water. In iAVS systems, sand serves as both a growing medium for plants and a bio-filter for fish waste. It provides an efficient way to recycle water within the system while promoting healthy plant growth and maintaining clean water for fish.
+Overall, sand is an essential component of iAVS systems due to its unique properties that promote healthy plant growth, support beneficial microorganisms, and provide effective water filtration. Its long history of use in water treatment further underscores its effectiveness as a filter media.
 ==== The iAVs Research Team ====
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 ===== How does iAVS work? =====
-iAVS works by creating a closed-loop system where fish waste is converted into nutrients for plants, which in turn filter the water for the fish. The system consists of a fish tank and plant bed, all connected by pipes and a water pump.
+An iAVS system is a closed-loop system that uses sand as a growing medium and bio-filter.
-Fish are fed and produce waste, which is pumped into the sand bed. The sand bed acts as both a bio-filter and growing media for plants. Beneficial bacteria in the sand break down the fish waste into nutrients that plants can absorb. Finally, clean water returns to the fish tank via gravity or a pump.
+The system consists of a fish tank, a grow bed filled with sand, and a pump that circulates water between the two.
+During each irrigation cycle, water is pumped from the fish tank up to the grow bed. The water is distributed evenly across the surface of the sand in furrows between raised ridges.
+These ridges help to concentrate detritus into narrower channels where it can build up along the bottom faster and help water move laterally more uniformly. By doing so, there is less chance to block surface pore spaces over a greater area which leaves more area (pores) available for atmosphere (oxygen) to enter easily into the root zone and microbes below the surface.
+As water percolates down through the sand in each furrow, it gets cleaned by beneficial bacteria that break down fish waste into nutrients that can be absorbed by plants. The clean water drains back to the fish tank via a drain pipe.
+It's important to note that during each irrigation cycle, it's recommended to water until saturation. This means watering until all of the sand in each furrow is fully saturated with water before draining back to the fish tank. This ensures that plants receive enough water and nutrients for optimal growth.
+The length and frequency of irrigation cycles will depend on factors such as plant growth stage, temperature, humidity, and other environmental conditions. In general, shorter cycles with more frequent watering are better for young plants with shallow roots while longer cycles with less frequent watering are better for mature plants with deeper roots.
+Efficient drainage and high oxygen levels in an iAVS system benefit the microbes and rhizosphere in several ways.
+Firstly, obligate aerobes require oxygen for cellular respiration to oxidize substrates such as amino and nucleic acids, ammoniacal-N, lipids, etc. to obtain energy. Therefore, increased oxygen concentration due to efficient drainage and high oxygen levels in the soil atmosphere promotes the growth of these beneficial microbes.
+Secondly, forced cellular (membrane) physical contact with oxygen due to individually smaller yet greater composite surface area contact and more uniformly distributed pore volumes provides a far greater colonized surface area in direct contact with oxygen. This means that more microbes can grow and thrive in the soil environment.
+Thirdly, temporal retention of and direct microbial contact/interaction with plant root exudate contributes to a more diverse and effective soil ecology. This means that the beneficial microbes are able to interact with plant roots more effectively, leading to better nutrient uptake by plants.
+These benefits to the microbes and rhizosphere also benefit water filtration by promoting the growth of beneficial bacteria that break down fish waste into nutrients that can be absorbed by plants.
+The recommended irrigation schedule for an iAVS system is to repeat the filtration/irrigation event at regular intervals during daylight hours for as many as eight times per day.
+The principle operational criterion is to incrementally and cumulatively circulate the equivalent of twice the total fish tank volume (at a minimum) through the filter bed every day. This ensures that plants receive enough water and nutrients for optimal growth while also maintaining clean water for fish in the system.
+However, it's important to note that the length and frequency of irrigation cycles may need to be adjusted based on factors such as plant growth stage, temperature, humidity, and other environmental conditions.
+Overall, an iAVS system operates by recirculating nutrient-rich water between a fish tank and a grow bed filled with sand. This closed-loop system promotes healthy plant growth while providing clean water for fish in an environmentally sustainable way. The use of furrows and ridges, watering until saturation, and monitoring drainage times are all important factors in ensuring optimal plant growth and system performance.
 The result is a sustainable and organic system that produces high yields of both fish and plants while using minimal water and no harmful chemicals or pesticides. With proper management of sand quality and nutrient levels, iAVS can be an efficient way to grow food in any climate or location.
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 ===== Benefits of iAVS =====