Overview of Hydroponic Cultivation Methods
Hydroponics is the science of nurturing crops without the use of soil, where the cultivated crops are supplied with nutrients through a fluid media. More often, hydroponic cultivation methods rely on water alone as the dominant medium through nutrients are supplied to the crops. According to Nicholls (1999, p.7), the benefit of hydroponics is that, it requires small space to grow large number of crops.
In addition, the system of growing crops using hydroponic methods facilitates faster growth of crops, and hence higher yields within a very short period. More so, arid and semi-arid areas can sustain crops using this cultivation method; since the plants usually grow faster and make good ground cover to reduce evaporation (Patten 2004, p.19). This paper will discuss various methods of cultivating crops using hydroponics system.
Commonly Used Hydroponic Cultivation Methods
Nutrient Film Technique (NFT)
The Nutrient Film Technique, also called water culture hydroponics, is one of the most productive methods of hydroponics used for growing commercial crops. In this method, crop roots are grown in light-tight and shallow channels that are supplied with nutrient in water circuits.
The nutrients are dissolved in water, where the solution is continuously allowed to circulate within the rooting system of the crops for about 20-24 hours per day. According to Keith (2003, p.23), the film of water flowing in the roots of the plant should be made as shallow as possible to facilitate efficient flow of oxygen within the rooting system of the crops as much as possible.
One main advantage of Nutrient Film Technique is that, it facilitates the growing of numerous crops in a very small space, thus most useful in space-limited areas like towns (Nicholls 1999, p.44).
It is also important to note that, this method does is not labor intensive since it requires no weeding or manual watering of the crops; since the nutrient solution is made to circulate automatically within the growing channels. This method is also advantageous in the sense that, it can support a wide range of crop varieties.
Aggregate Culture Hydroponics
Aggregate culture hydroponics is also called passive sub-irrigation. This is a technique of growing crops in sand or gravel, where water mixed with nutrients is pumped in the gravel tank where the crops are planted in. One advantage of this method is that, the plants are not necessarily held in water film, since they can acquire anchor from the gravel or sand in the container (Howard 2003, p.26).
Once the tank is filled up with water mixed with nutrients, the water can easily be drained away after the roots get moistened and absorb enough nutrients. The water drainage in this case can be drained up after 5-8 hours of flooding. By pumping or draining the water in the rooting system, aeration in the rooting region of the crops is facilitated, making the crops grow healthy (Patten 2004, p.95).
According to Keith (2003, p.37), passive sub-irrigation involves the transportation of water and nutrients using capillary action. As a result, it is considered as one of the best methods of hydroponics since there is minimum utilization of labor.
Since the rooting system of the plants is highly aerated, root rotting is least experienced using this method as compared to other methods. Further, the supplementary ambient humidity made available through evaporations ensures low risks of root rot in the crops.
Aeroponics
Aeroponics is a method of hydroponic cultivation where oxygen is used in the nutrient solution, instead of using water. In this method, moisture-proof and dark containers are used, where the roots of the crops being grown are allowed to grow in enclosed containers.
As reported by Nicholls (1999, p.69), the system of aeroponics involves a system of misting that is used to ensure that the roots are humid enough, and that they absorb enough nutrients. To ensure that the crops’ roots are sprayed directly with the nutrient solution, a spray nozzle is located in the container.
One important thing to consider while using this system in growing crops is that, the spray ought to be kept constant at moderate pressure. Alternatively, it is advised that the spray be turned on for about 2o minutes, and then be turned off for about 40 minutes alternatively. To reduce any chances of roots from rotting, it is advisable that some fungicides be added in the nutrient spray (Howard 2003, p.51).
The levels of oxygen in the sprays are enhanced by ensuring continuous circulation of the spray system, which makes the nutrients to be broken down into smaller particles. The use of aeroponics is advantageous in the sense that, there are low chances of the rooting system to be contaminated with pathogens since the containers in which the plants are planted in are air-tight.
Conclusion
It has been noted that, hydroponics involves the use of nutrient solutions to grow crops without using soil as anchorage base. The main commonly used hydroponic cultivation methods are nutrient film technique, aggregate culture hydroponics and aeroponics. One of the common advantages for all hydroponic methods is that, they are less labor intensive, and that they utilize minimum space for growing large number of crops.
Reference List
Howard, R. 2003. Hobby hydroponics. New York: CRC Press.
Keith, R. 2003. How-to hydroponics, 4th edition. London: Futuregarden Publishers.
Nicholls, R. 1999. Beginning hydroponics revised ed. New Jersey: Running Press.
Patten, F. 2004. Hydroponic basics. Boston: Van Patten Publishing.