Wicking bed

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A wicking bed is an agricultural irrigation system used in arid countries where water is scarce, devised by Australian inventor Colin Austin. [1] It can be used both in (arid) fields as in containers. [2] Besides use in fields/containers outdoors, it can also be used indoors (i.e. greenhouse).

Contents

The system is designed to increase food production while using approximately 50% less water than traditional irrigation by utilizing underground water reservoirs filled with decomposing organic matter and the process of evaporation. [1]

Despite being an irrigation system (which can even be fitted with automated refill capability via rainwater tank and float-valve), it remains relatively low-tech. [3]

There are several commercially available wicking bed products, including recycled plastic wicking "cells" that are reported to reduce water use by up to 80% when compared to above ground irrigation

Advantages

There are several benefits [4] to wicking beds, many of which arise due from the water moving upwards from below:

Water Efficiency

Watering from below produces less evaporation [5] than top watered methods. Significant water savings are generated given the moisture gradient is the reverse of that from watering methods.

Deeper Roots

Plant roots seek out moisture. Deep watering is often recommended for this reason. Wicking beds have a moisture gradient that encourages roots downwards. [4] This gives more stable plants that are healthier and less prone to water stress when surfaces dry out

Lower Fungal Disease

The surface of a correctly constructed wicking bed is generally dry unless it has been raining. This means a lower level of surface fungal issues. This particularly benefits vegetables prone to fungal infections, such as cucumber, tomato, and squash varieties

Surface Pest Control

Slugs, snails, and other mollusks much prefer a moist surface. They find wicking beds more challenging to establish in and move between plants.

Nutrient Retention

Soluble fertilisers often wash through soil into the water table. However, in a wicking bed, these are retained in the reservoir to be wicked back up through the soil. This means less fertiliser is needed. [6]

Disadvantages

Deep Rooted / Invasive Plants

Water will only wick up 300-400mm [5] in potting mix. This is great for vegetables and other relatively shallow-rooted plants but unsuitable for deeper rootstock. Shrubs, trees, or anything with an invasive root structure may not benefit from being grown in a wicking bed.

Salinity

There can be a build-up of salt [7] in a wicking bed. They must be flushed from time to time. Well-constructed beds with a good drain typically get flushed or diluted in heavy rain, which is not usually an issue. However, in a long-term drought, it is important to flush through the water occasionally.

Anaerobic decomposition

It is important to build in an air gap in a wicking bed, between the water and the soil, with only 5-10% of the area crossing that boundary for wicking. This stops the soil from getting too sodden and helps prevent an odorous anaerobic decomposition from occurring. A badly constructed wicking bed may even have organic matter in the reservoir layer below the water line, which can trigger the same thing. The use of charcoal in the lower areas of the mix is recommended to keep the dam soil sweet.

Cost/Effort

No doubt it costs more up front to establish a wicking bed. However, the effort is generally returned in higher yields and much lower maintenance.

Related Research Articles

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Hydroponics is a type of horticulture and a subset of hydroculture which involves growing plants, usually crops or medicinal plants, without soil, by using water-based mineral nutrient solutions. Terrestrial or aquatic plants may grow with their roots exposed to the nutritious liquid or the roots may be mechanically supported by an inert medium such as perlite, gravel, or other substrates.

<span class="mw-page-title-main">Irrigation</span> Agricultural artificial application of water to land

Irrigation is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been developed by many cultures around the world. Irrigation helps to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation is also employed to protect crops from frost, suppress weed growth in grain fields, and prevent soil consolidation. It is also used to cool livestock, reduce dust, dispose of sewage, and support mining operations. Drainage, which involves the removal of surface and sub-surface water from a given location, is often studied in conjunction with irrigation.

<span class="mw-page-title-main">Soil salinity</span> Salt content in the soil

Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the gradual withdrawal of an ocean. It can also come about through artificial processes such as irrigation and road salt.

<span class="mw-page-title-main">Evapotranspiration</span> Process by when water moves into the air from plants and soil.

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<span class="mw-page-title-main">Nutrient management</span> Management of nutrients in agriculture

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<span class="mw-page-title-main">Soil moisture sensor</span> Instrument to measure soil water content

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<span class="mw-page-title-main">Sub-irrigated planter</span>

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<span class="mw-page-title-main">Pulse drip irrigation</span>

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References

  1. 1 2 Lolo Houbein (2012). Outside the Magic Square: A Handbook for Food Security. Wakefield Press. p. 104. ISBN   978-1-74305-011-8 . Retrieved 7 July 2013.
  2. Building a Wicking Bed
  3. How to Build a Low-Tech, Automated Wicking Bed (AKA ‘sub-irrigated planter’)
  4. 1 2 "Evaluating the Efficiency of Wicking Bed Irrigation Systems for Small-Scale Urban Agriculture". ResearchGate. Retrieved 2021-07-20.
  5. 1 2 Semananda, Niranjani P. K.; Ward, James D.; Myers, Baden R. (December 2016). "Evaluating the Efficiency of Wicking Bed Irrigation Systems for Small-Scale Urban Agriculture". Horticulturae. 2 (4): 13. doi: 10.3390/horticulturae2040013 .
  6. KIRKHAM, MB; D, GABRIELS (1979). "WATER AND NUTRIENT UPTAKE OF WICK-GROWN PLANTS". Water and Nutrient Uptake of Wick-Grown Plants.
  7. Semananda, Niranjani P. K.; Ward, James D.; Myers, Baden R. (December 2016). "Evaluating the Efficiency of Wicking Bed Irrigation Systems for Small-Scale Urban Agriculture". Horticulturae. 2 (4): 13. doi: 10.3390/horticulturae2040013 .