A Review on Hydroponics and the Technologies Associated for Medium- and Small-Scale Operations

Abstract

According to the Food and Agriculture Organization of the United Nations, the world population will reach nine billion people in 2050, of which 75% will live in urban settlements. One of the biggest challenges will be meeting the demand for food, as farmland is being lost to climate change, water scarcity, soil pollution, among other factors. In this context, hydroponics, an agricultural method that dispenses with soil, provides a viable alternative to address this problem. Although hydroponics has proven its effectiveness on a large scale, there are still challenges in implementing this technique on a small scale, specifically in urban and suburban settings. Also, in rural communities, where the availability of suitable technologies is scarce. Paradigms such as the Internet of Things and Industry 4.0, promote Precision Agriculture on a small scale, allowing the control of variables such as pH, electrical conductivity, temperature, among others, resulting in higher production and resource savings.

Indoor Vegetable Production: An Alternative Approach to Increasing Cultivation

“…In general hydroponics have numerous merits but also have demerits. These attributes have been articulated by several authors [ 28 , 93 , 96 , 99 , 100 , 104 , 105 ]. The advantages include (i) limited space requirement and therefore permits widespread use in many places including in space, (ii) elimination of seasonality and increased frequency of production as crop cycles can be repeated as many times as possible, (iii) eliminates the need for cultural practices like crop rotation and weed control required in open field and soil-based production systems, (iv) offers opportunities for infusing ergonomics into certain aspects of leafy vegetable crop production such as raising lettuce, kale, mustard, spinach, endive, Swiss chard and many Asian greens and small fruits like strawberries off the ground to a desired height to ease cultivation and harvesting activities, (iv) reduce transplant shock and provide 30% to 50% faster plant growth rates compared to soil-based crop production methods, (v) offer enhanced nutrient use efficiency permitting at least 20% higher yields compared to soil-based cultures, (vi) the absence of soil in this systems, the recycling of the nutrient solution coupled with their operation in a controlled environment helps minimize the incidence of plant diseases and pests and hence the regular need for use of pesticides, (vii) hydroponically grown plants use considerably less water (80–95%) than those grown in the field because of less water loss through evaporation providing savings on water use in crop production.…”

“…IF spans several subject areas as such it is difficult to provide a completely exhaustive review covering all its relevant aspects. As a result, published reviews on IF turn to focus on specific topics such as greenhouse types and their structural components [ 22 ], components of soilless mixes and potting mixes [ 23 ], energy efficiency [ 24 ], IF applications in various environments including tropical and extreme [ 25 , 26 ], light technologies [ 27 ], hydroponic technologies [ 28 ], aeroponics [ 29 ], aquaponics [ 30 ]. Other reviews and reports have provided broader reviews with varied foci such as the history, industry landscape and impacts and discussions on some of the structures and production systems [ 10 , 28 , 31 , 32 , 33 , 34 , 35 ].…”

IoT-Based Monitoring System Applied to Aeroponics Greenhouse

“…The lifetime of the solution is of the utmost importance and will depend on timely adjustments made to the pH, electrical conductivity and water level. To exclude changes in the nutrient solution, the volume level in the storage tank must remain constant, replenishing the water absorbed by the plants and lost by evapotranspiration, otherwise, the concentration of the salts will change, affecting the healthy growth of the plants [ 11 ].…”

De-novo transcriptome assembly and analysis of lettuce plants grown under red, blue or white light

“…These systems allow the farmer to use less water and manpower to produce food-safe high-quality produce more precisely 4 , 5 . Production of plants under a controlled environment has many advantages over conventional farm-based agriculture.…”

“…Furthermore, the location of the growing region, season, nutrient inputs, agronomic practices, light parameters, and post-harvest practices can affect the phytochemical content and nutritional composition of lettuce. In modern-day agriculture, lettuce is successfully adapted to the hydroponic-based high-throughput production system.These systems allow the farmer to use less water and manpower to produce food-safe high-quality produce more precisely 4,5 . Production of plants under a controlled environment has many advantages over conventional farm-based agriculture.…”