Hydroponics
How It Works
Hydroponics is the practice of growing plants or crops in nutrient-rich water without the use of soil.[1] Instead plants are grown by exposing their roots to a constant supply of a fertilizer solution. The crops are supported by a material such as rockwool, which is similar to coconut fibers in appearance and neither consumes or contributes nutrients to the system but is very absorbent.[2] The benefits of hydroponics include:
- more efficient use of water because the water is filtered and recycled instead of getting leached into the soil[3]
- increased yield versus conventional farming methods[4]
- faster growth due to less mechanical hindrance on roots which tends to slow down growth.[5] This means that due to the nature of having the plants above ground in hydroponic farming, the plant’s roots have an easier time growing when compared to standard farming where roots are deep in the soil.
- climate independent farming allows plants to be grown year-round at the same quality due to lab-like control on environmental conditions[6]
- and no chemical deterrents as threats from pests are negligible.[7]
Case Study
A 2018 study on hydroponics from the Journal of Soil and Water Conservation provides an overview of the benefits over standard soil farming. It reports that hydroponics produces crops that grow faster regardless of season, are not in danger of pest infection, and conserves resources like water better than conventional farming. Hydroponic crops can be harvested sooner and have a greater yield.[8] Irrigation water usage can be reduced by up to 90% in hydroponics.[9] All in all, hydroponics provides an advantage in nearly every aspect of farming over traditional soil farming
Aquaponics
How It Works
Aquaponics is a combination of two types of alternative agriculture systems: hydroponics (see above), and aquaculture.
There are two categories of aquaponics systems: single-loop/balanced and double-loop/de-coupled. In a balanced system, fish and other aquatic animals are bred within the same system as the plants, using the waste produced to fertilize the plants, while the plants filter water for the fish.[12] This is a closed-loop of nutrient recycling, thus conserving up to 98% of water used daily.[13]
The second category of aquaponics systems is de-coupled. In this type, the fish and the plants are not necessarily within the same system, but rather fish waste may be mineralized or turned into solids, before being used as fertilizer. De-coupled systems are especially common in more temperate climates.[14]
Advantages & Disadvantages
Depending on where water is sourced, as well as what aquatic life is used, aquaponic systems may lack nutrients such as Ca, K, and Fe,[15] which could be supplemented in other forms. In addition, some commonly used pesticides, such as copper sulfate, Rotenone, and sulfur, are toxic to fish.[16]
There are several advantages to aquaponics. Due to fish being cold-blooded, there is less risk of E. coli and similar agricultural diseases. The use of fish also reduces the amount of synthetic fertilizers needed. This contributes to a lower amount of chemicals, including a lower rate of pesticide use through targeted applications.[17]
Another quality of aquaponics of being able to be situated at any site, including rooftops or other unproductive sites, reduces the need for land acquisition and the pressure on currently undeveloped land.[18] This is greatly advantageous considering the growing unavailability of farmland due to urban growth and soil degradation.
Aquaponics also has many options for planting media, which include coconut, peat, and vermiculite.[19]
Case Study
A study in Baltimore, Maryland, on a small-scale aquaponics operation suggests that aquaponics is similarly constrained by the same factors as other types of small-scale agriculture: labor shortages, budget constraints, and pest control. It reports a daily water loss of about 1% with variations in monthly water use[20]. Any water losses could be offset by gathering natural rainwater due to the small operation scale. If properly secured, rainwater could replace the traditional use of piped/well water in aquaponics.
Both the water and the air of the system were heated, and water heating was measured to be more efficient, consuming 19, 354 kWh and 19, 698 kWh in 2013 and 2014 respectively when combining propane and electricity use.[21] To reduce the need for heating, planter covers could be used to trap rising warm air from the water, as well as several other strategies. Because of this, it is advantageous in colder climates to situate aquaponics systems indoors instead of in greenhouses, whereas in warmer climates greenhouses would suffice.[22]
Aeroponics
How It Works
Aeroponics is the process of growing plants in the absence of soil or an aggregate medium, and instead growing them in an air or mist environment.[23] The plants are grown in a closed or semi-closed environment by spraying the plant’s dangling roots or lower stem with a nutrient-rich water solution.[24] The environment is ideally kept free of pests and diseases, but if not entirely closed off from the outside, they could still remain a threat.[25]
Case Study
In a study done on potatoes, aeroponics is helpful for growing potatoes in developing countries with low soil fertility, soil-borne diseases, poor water quality, and pests, all of which severely hamper the production of this cash crop.[27] Aeroponics use a small amount of water, so in desert areas, this agricultural method is much more efficient.[28] The success of aeroponics is independent of soil quality, and is not affected by seasonal adverse effects such as hot, dry, cold, or windy weather.[29] Aeroponics provides the highest yield per unit area per year for all known agricultural systems due to the closer spacing between each plant.[30] Greenhouses using aeroponics can be built around city centers and markets to reduce cargo and provide consumers with fresh goods.[31]
However, there are some disadvantages to aeroponics. It is costly to use aeroponics to produce goods for a long time. and the equipment can sometimes be expensive due to the well-designed system requiring advanced equipment.[33] Aeroponics is not easy either, as growers need an appropriate amount of knowledge and a specific level of proficiency in order to operate the system which gives the crops their nutrients.[34] Finally, the nutrients must be supplied at specific concentrations and if there is an oversupply, the plants will die, and since there is no solid culture, they can’t absorb the nutrients.[35] Although the study reviews aeroponics usage in developing countries, this information demonstrates how efficient and effective this farming technique could be if we implemented it.