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--- introduction [2023/06/09 19:56] – [How does iAVS work?] 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? =====
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 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.
-It's also important to note that long drainage times can have negative effects on plant growth. If drainage times are too long, the sand in the furrows can become waterlogged, which can lead to root rot and other issues. Therefore, it's important to monitor drainage times and adjust irrigation cycles as needed to ensure optimal plant growth.
+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 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.
+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.