Enhanced Agricultural Productivity Using Hydroponics Technique: A Smart Farming System

Abstract

Hydroponic farming is one potential solution to the lack of arable land diminishing the capacity of agriculture. The hydroponic method of crop production has proved successful for precision farming in growing both flowers and vegetables. It requires fewer energy requirements than traditional agriculture because it employs fertilizer solutions under heavily controlled environmental conditions in limited areas. Hydroponic systems can be used as a treatment method for partially treated wastewater or reclaimed water before its discharge into the environment since plants have the ability to absorb nutrients, toxic metals, and emerging contaminants. Farmers engaged in hydroponic farming benefit from a wide range of significant advantages by enhancing their income through introducing quality products for a sustainable community. The newly created technology also arrived at the perfect time because traditional farming practices do not work with diminishing water levels. Plants may now be grown in any greenhouse or nursery, regardless of the season, as long as the necessary infrastructure is in place.

1. Introduction

Environmentally friendly soilless agricultural production methods control inputs like water, pesticides, and fertilizers to produce farm output. Furthermore, soilless agriculture makes the best use of available energy. It offers significantly cleaner and hygienic products than soil-based agriculture [1]. The technology required to use soilless agricultural techniques has rapidly improved, expanded, and gained a lot of significance in recent years. This technology is relevant to farming methods that use minimal water and little land while allowing total control over all agricultural variables. A number of things affect traditional farming [1]. A number of elements, including soil nutrients, climatic circumstances, and inappropriate soil structures for cultivation, may have a negative effect on conventional agriculture. Additionally, soil-borne pathogens and pests can dramatically lower overall productivity. Consequently, the use of agricultural methods in a controlled environment has become increasingly important recently. The most significant kind is “soilless agriculture,” which has gained popularity as a result of changing climatic conditions and dwindling agricultural land [2]. Approximately 12% of the earth’s surface (1.5 billion hectares) is used for agriculture [3]. According to the FAO’s 2030/2050 forecast assessment, the amount of arable land per person in developing countries, wealthy countries, and the entire world would decrease annually. Although both the world population and food consumption are expanding, the average quantity of arable land per person is decreasing yearly [3]. This suggests that some countries may face food crises in the future. Additionally, the amount of arable land is decreasing daily due to climate change and the misuse of agricultural land for non-agricultural purposes [3]. Nations have looked for a variety of solutions to deal with the population expansion that threatens food security. The solution currently requires international agricultural investment and soilless farming methods. The depletion and contamination of freshwater resources are additional key problems in agriculture, in addition to the decreasing area of arable land.

One of the well-liked methods of indoor soilless farming is hydroponics, which uses less fertilizer and offers greater protection against pests and adverse weather conditions [4]. High-value crops can be grown hydroponically better than low-value field crops [5]. In open fields and naturally ventilated poly buildings at farming systems, a variety of cool-season vegetables were assessed utilizing vegetative and yield metrics [6]. Using conventional agronomical approaches, the yield of a crop is significantly impacted by climatic changes, pests, and diseases, which results in low-quality output. Using the hydroponic technique, mineral fertilizer solutions dissolved in water act as a solvent to enhance plant uptake of soil nutrients. The hydroponics techniques are divided into groups based on the availability, positioning, and method of administering nutrient solutions to plant roots [6]. It has been discovered that crops produced in hydroponic systems produce more continually throughout the year and need less time to grow than crops cultivated in conventional systems. The growing medium in hydroponics directs water and nutrients while enabling ample oxygen to reach the plant’s roots. Different types of hydroponic systems work well with varied growing materials [7]. Despite the absence of soil-borne pests and diseases, soilless growth techniques like hydroponic systems have some risks, most notably the existence of waterborne pathogens [8]. These risks negatively affect hydroponic recirculating systems where bacteria can build up over time. The issues with hydroponics also originate from the requirement for financial outlays and technical expertise to use the control systems. Rufi-Salis et al. [9] explore the many hydroponic fertilizer usage reduction strategies in order to stop nutrient discharge into the environment. Closed systems that use water efficiently and preserve space have quickly become vital under these circumstances when health problems and access to wholesome food are significant difficulties. Even those with no interest in farming have recognized the value of organic farming and attempted to develop its products.

2. Different hydroponic cultivation techniques

Contrary to conventional farming, hydroponics does not use soil to grow food. This method involves growing plants on artificial or natural substrates so that the roots may easily draw nutrients from a prepared nutrient solution (Figure 1). The implementation of various hydroponic farming techniques varies depending on the type of plant, regional climate, and financial constraints, among other things [10]. In Floating Root System or Deep Water Culture (DWC) system, plant is held above the water line by polystyrene, cork bark, or wood, among other materials, with only the root submerged in the nutrient solution. In drip irrigation, a controlled flow of fertilizer solution is injected straight into the plant roots. At regular intervals, the solution is administered, and in closed systems, any remaining solution is disposed of in the storage tank [10]. In aeroponics, a sprinkler system periodically sprays nutrients onto the plants, which have roots that hang down in the air. The key benefit of this method is that it does not need an airing system because oxygen is carried in the fertilizer solution that is sprayed and is the best method for growing tubers and roots. Nutrient film techniques (NFT) are similar to those in a floating root system, but instead of being entirely submerged in the nutrient solution, they are instead suspended in a liquid stream that is passing via a pipe system [10]. NFT needs more energy and components to function, even though it uses less nutritional solution than the floating root system. The flow of nutritional solution can be continuous or irregular, and the excess solution returns to the storage tank via gravity. In the Ebb and Flow method, a tray with plants in it receives regular fills of nutrient-rich water blasted up from a reservoir below. The technology employs gravity to recycle the water by returning it to the reservoir [10]. In contrast, the aquaponics method takes advantage of the symbiotic relationship between plants and animals to create a productive system where fish waste meets the nutritional needs of the plants. A healthy micro-ecosystem is created when fish tank water is recycled through the uptake of nutrients and the microbial nitrification and denitrification processes [10].

Figure 1.

Interconnection of hydroponic with precision agriculture and internet of things to meet global food demand.

3. Essential tools required for indoor hydroponic system

Ten essential tools that indoor hydroponic gardeners should keep are a pH meter (to measure the acidic or basic nature of water), nutrient test kit (to measure different nutrients in the water), TDS meter (to measure dissolved solids, salt, minerals, and other concentrates in the water), timer (to track the watering time and lighting plants), thermometer (to keep track of the temperature in the grow room), hygrometer (helps you keep track of the humidity in the grow room), watering can or hose (to water plants regularly), scissor or trimmer (required for plant growth as it helps the plant focus its energy on producing more leaves, flowers, and fruits), measuring cups (used to measure the nutrients adding to the water), and grow room glasses (to protect your eyes from the bright grow lights and avoid any eye damage). The test equipment for automation kits used in soilless agricultural systems is expensive. As a result, the control kit acquired as part of the project will be quick and simple to use, enabling its widespread adoption due to its low cost and simplicity. A control kit was created using an Arduino microcontroller, four distinct sensors, add-on tools, and project coordinator-written software [1]. Although many industries use these controller cards now, their utilization in agriculture is not as high as it could be. Furthermore, such technology can regulate the temperature, pH, dissolved oxygen, electrical conductivity, and pH of the solution in systems that use the soilless farming method [1].

4. Nutrient solution used in hydroponics

With the exception of carbon, hydrogen, and oxygen, all necessary nutrients are delivered to the plant through the nutrient solution in hydroponics. With the exception of iron, which is given as an iron chelate to increase its availability, inorganic fertilizers are utilized as suppliers of nutrients. Although some inorganic acids are also employed, the majority of fertilizers used in hydroponics to generate nutrient solutions are highly soluble inorganic salts [11]. Depending on the crop and plant stage, the nutrient solution makeup varies. In hydroponics, soluble fertilizers including ammonium nitrate, calcium nitrate, phosphoric acid, and nitric acid are employed [11]. Although these formulations are sold commercially in liquid or solid form, the salt, mineral, and fertilizer mixture can also be made from scratch. It is crucial to note that different formulations are needed for different growth stages of plants. For instance, during the vegetative state, a plant grows foliage until it is ready to flower or ripen its roots, at which point the plant needs a nutrient solution high in phosphorus to develop strong roots. Finally, the plant needs nutritional solutions with high concentrations of K and low amounts of N during fruit ripening. According to the N-P-K concentration stated in weight percent, solutions that are commercially available codify the macronutrient contents as a three-digit sequence. Leaching the solution before adding it to the hydroponic system enables the addition of organic nutrients like compost, a mixture of vegetable waste, urine, manure, and dead animal parts. This kind of tea can potentially replace the conventional inorganic fertilizers used in hydroponics. However, adding such components to the formulation runs the risk of introducing unwanted parasites or bacteria, therefore it must be thoroughly examined before being added to the hydroponic system. If you want the solution to persist as long as possible, the pH, electrical conductivity, and water level must be adjusted as soon as feasible. In order to prevent variations in the nutrient solution, the volume level in the storage tank must be constant, replenishing the water received by the plants and lost through evapotranspiration. It was generally recommended to switch the tank solution every two to 3 weeks, depending on the crop, to provide the tank with a thorough cleaning and disinfection [12].

4.1 pH in hydroponics nutrient solutions

The pH of a nutrient solution, which is measured on a scale of 1–14 to indicate a solution acidity or alkalinity, is a crucial chemical characteristic. Water has a pH of 7, indicating that it is neither basic nor acidic at normal temperature. If the pH is more than 7, the solution is basic; otherwise, it is acidic. The majority of publications concur that the pH of the nutrient solution must be between 5 and 7, as nutrients stay soluble in this range [13]. The solubility of Fe and H2PO4 diminishes, causing Ca and Mg precipitates as well as other chemical interactions between the components of the nutritional solution, which prevents the absorption of iron, boron, copper, zinc, or manganese if pH is more than 7. However, the adsorption of nitrogen, phosphorus, potassium, calcium, magnesium, and molybdenum is prevented if pH is lower than 5. Hazardous contamination may occasionally be caused by the supply of some micronutrients, such as manganese [14].

4.2 Electrical conductivity of the solution

An estimation of the total ion concentration in a solution is electrical conductivity or EC. Low EC values in this situation point to a lack of nutrients in the form of ions, while high values could produce salt stress in the plant [15]. As a result, EC should be kept within a target range because it has a substantial impact on crop quality and growth [16]. Additionally, since this measure does not specifically indicate the concentration of each element in the nutrient solution, it is crucial to give fertilizers in concentrations that the plants can absorb after measuring EC.

4.3 Nutrient solutions sterilization

Hydroponic systems require an aseptic environment to effectively generate high-quality products, but it is challenging to maintain sterility in the area around plant roots [17]. The most noticeable sign of a damaged plant is leaf withering, which is brought on by the fungus Fusarium and Verticillium. The roots of the plant are also threatened by other parasite species including Pythium and Phytophthora. Unfortunately, using fungicides in hydroponics without endangering consumer health is not possible [18]. From a sustainability perspective, recirculating the nutrient solution lessens the quantity of water consumed and waste that must be disposed of, but it is not always practical to design systems that balance resource consumption, energy use, and cost. Given the advantages and disadvantages of each option individually, combining the hydroponic infection prevention techniques may be the best course of action to address the fertilizer solution sepsis problem.

5. Digital twin in smart agriculture

One effective soilless method is hydroponics, which has benefits including reduced water use, improved output, and the absence of chemical weed or pest control solutions. It is essential to use the most cutting-edge technologies available to increase hydroponics efficiency. IoT applications for smart hydroponics greenhouse farming are shown instrumental [19]. The primary benefit of a DT is that the virtual unit can forecast how its physical twin will function, thereby foreseeing potential problems and optimizing the entire system. Increasing output, reducing waste, protecting natural resources, and maintaining quality and other production standards are a few examples of this. Hydroponic and soil-based farms may respond differently to many environmental factors [20]. Predictive analysis and quick control are required in the hydroponics farming method for problems including nutrient solution management, pathogen management, weed management, and environment management. Among these, the dietary approach stands out as a crucial factor in determining high-quality production. The productivity and yield of the hydroponic farm are directly impacted by nutrient intake and pH control [21]. The availability of nutrients for plant uptake may be constrained by a higher pH value due to the presence of insoluble and inaccessible ions. The pressure that the ions of the nutritional solution exert on it can be measured using electrical conductivity (EC). The ideal EC for each crop varies based on the environment [22, 23]. Higher EC values translate into higher osmotic pressure, whereas lower EC values could be detrimental to the health and productivity of plants. However, it is not advisable to consistently apply nutritious solutions. According to studies, highly concentrated nutrient solutions encourage excessive nutrient consumption, which may have harmful effects [24]. Growers may benefit from an accurate predictive model on the right amount of nutrients to add for a certain crop at a specific time in order to reduce the negative effects of nutrient overuse. The capacity of hydroponic farms to adjust multiple parameters like pH, EC, and temperature can only be used with the aid of more accurate and predictive models. High nutrient solution temperature in hydroponics can cause a number of problems, including the plant refusing to absorb nutrients through the roots and finally going into survival mode [25]. This is similar to how EC and pH can affect the plant. Higher water temperatures in the fertilizer solution are also conducive to microorganisms rapidly proliferating. These may also develop in the root zone, which may cause several plant diseases [26]. Even the frigid temperatures of nutrient solutions are not ideal for plant growth. Throughout the course of a plant’s life, the root zone should be a comfortable environment [6].

Digital twins (DT) encompass a variety of technologies, including artificial intelligence, augmented reality, the Internet of Things, communication technologies, embedded technologies, big data, processing techniques, data security, and cloud computing, among others [27]. DT can be characterized as an adaptive model of a living or non-living physical system that aims to construct, monitor, and enhance the performance of its actual counterpart and give end users a more realistic experience [28]. The lifecycle of a real machine, for example, can be applied to DT at any point in time. DT can be applied to the design of the product, to enhance the physical model, and to perform preventative maintenance. Despite the fact that DT technology actively participates in the development and marketing of several manufacturing and aviation. With the use of meteorological information, the DT idea can be used to improve the forecasting of nutrient solution temperature [29]. A predictive model for the temperature of the nutrient solution can be created by utilizing DT to determine the relationship between nutrient solution temperature and meteorological parameters. Farmers can utilize DTs to predict how well such cooling devices would function when they are used in a hydroponics farm without actually installing the actual units. It assists the farmers in developing a practical first plan for their farm and evaluating the performance impacts of adding new resources, including fans and heaters.

6. IoT-based hydroponics system

The application of modern information and communication technologies (ICTs) in agriculture is the foundation of the high-tech, expensive “smart farming” system. In IoT-based smart farming, a system is developed for sensor-assisted crop field monitoring and irrigation system automation [30]. Two businesses, ATLAS Scientific and Libelium Waspmote, offer electronic sensors and microcontroller-based systems for detecting environmental factors and water quality [31]. According to the surveys, many scientific articles have examples of these solutions [32, 33]. It is essential to use other important ICTs, such as big data [34], blockchain [35], and neural networks [36], which have been successfully employed in other scenarios like these to produce precise and efficient agriculture. Examples of IoT applications in agriculture include open-field farming and greenhouse cultivation [37, 38]. The most often observed metrics are temperature and humidity [37, 38], however other elements including light [39] and crop-specific traits [37] are also regularly noted. Several studies monitored variables such as soil moisture, temperature, humidity, and light in order to automate the irrigation system [39, 40]. The iPONICS system makes an effort to take advantage of some of the technologies mentioned above in order to offer a simplified, inexpensive, yet creative hydroponic solution that can be used by even hobby-type hydroponic systems [31]. The design and execution of a cutting-edge, low-cost IoT-based hydroponics monitoring and control system were demonstrated in many circumstances [31]. The system is made up in particular of a specialized wireless sensor network for controlling the watering process and monitoring the crucial hydroponics parameters. It offers the customer a simple web-based application to keep tabs on their crops while also alerting them with the proper alarms and warnings. This makes it much easier to observe numerous hydroponic greenhouses with little effort and without having to take any action. The proposed system specifically aims at hydroponic cultivation, in contrast to the systems covered previously. Using Arduino, Raspberry Pi 3, and TensorFlow, a prototype for the growth of a tomato plant was created [30]. Machine-to-machine connection and autonomous, intelligent control of the hydroponic system is made possible by the use of IoT. The system as it was designed is complex enough to give the necessary control action for the hydroponic environment based on the numerous acquired input parameters [30].

7. Small and medium-scale food production using hydroponic

Small firms have sprung up as a result of indoor production, boosting regional economies. The profitability of an indoor urban vertical farming (IUVF)-based company to that of a greenhouse was compared [41]. Due to the greenhouse’s high maintenance costs, the results demonstrate that IUVF is more profitable on a small- to medium-sized scale than it is in the greenhouse. In order to set up a hydroponics farm, it is important to take into account the cost of various pieces of equipment, such as heating, ventilation, air conditioning (HVAC), fans, irrigation systems, control systems, railways, and lighting. The adoption of hydroponics as a farming technique is significantly hampered by the enormous initial cost of the system [42]. Thus, it is crucial to create new, better goods and services to aid the hydroponic system. Such technologies must be scaleable to meet growers’ needs, not just for large-scale operations but also for medium- and small-scale ones, taking into account the limited amount of space that may be used for farming. Hydroponics is essential for the establishment and might make a substantial contribution to achieving sustainable development goal 11 (SDG 11). However, it requires the creation and uptake of the right technology. A framework that integrates heterogeneous devices on various computing layers to monitor and optimize the production process was designed to describe some technologies suitable for indoor farming [43]. In addition, they created the AgroRobot, an aeroponics-based robot for growing microgreens. Additionally, a number of project accessories, like culture trays, are created utilizing 3D printing technology. Hydroponics industry applications of Agriculture 4.0 are already well underway. A graphical user interface for indoor hydroponic production of leafy species, for instance, was created by the open-source Mycodo Environmental Regulation System [10].

8. Interlink between agriculture 4.0 and hydroponics

Hydroponics fits well into the framework of Agriculture 4.0 as large corporations increasingly use developments in indoor vertical farming, artificial intelligence, and plant biology to create a wide range of products [44, 45]. Hydroponics has secured a key position in the development of future food production systems, supported by cutting-edge, creative technology and a strong scientific foundation to ensure high output. Hydroponics may be very helpful in achieving SDG 11 which includes sustainability and resiliency of urban areas. The challenge is to adapt these technical developments to medium- and small-scale businesses that are prevalent in urban and peri-urban populations. Due to technological breakthroughs in electronics, which have led to the adoption of equipment, temperature and moisture sensors, aerial imaging, and GPS, modern farms. Precision irrigation, pest control, plant disease identification, and production management were all made possible by the integration of ideas such as artificial intelligence, the Internet of Things, and big data into autonomous food production systems. This revolution, dubbed “Agriculture 4.0,” promises to seamlessly combine agricultural practices with cutting-edge technology, such as sensors, gadgets, machinery, and information technology. Until ideas like eco-agriculture [46], agro photovoltaics [47], and precision agriculture [48] are included in global farming practices and culture, Agriculture 4.0 has not yet been widely accepted. In order to achieve it, agriculture and technology will need to create a common ground for both farmers and technologists. The first step is to understand the best uses of technology and demand innovations that address the true needs of the food supply and value chains in order to meet producer expectations for highly improved products, services, and processes to support sustainable and effective food production in urban and peri-urban settlements. Aerial and satellite photography, robots, temperature and moisture sensors, GPS technology, and other sophisticated technologies are just a few of the ones that are being used more and more to enhance the entire food value chain and make businesses safer, more efficient, and more environmentally friendly [49].

9. Conclusion

Agriculture is a key component of the Indian economy. As a result of rising food demand, rising labour costs, unfavorable environmental conditions, and dwindling agricultural land, indoor farming techniques like hydroponics and aeroponics are becoming more and more popular. Hence, there is no mention of soil-based on the conventional manner of growing plants. That indicates that plants can develop if certain conditions are met. In this context, the concept of hydroponic farming is introduced in the farming system. In this method, mineral fertilizer solutions in water serve as a solvent, allowing plants to absorb nutrients from the soil more effectively. A variety of flowers, vegetables, and herbs can be grown with hydroponics. Due to the advancement of IoT, farmers may now automate hydroponic culture. Monitoring of water level, pH, temperature, velocity, and light intensity can be done with the help of IoT. For instance, the water tends to freeze in some areas throughout the winter, which could entirely obstruct the agricultural process. The water temperature sensors on the hydroponics farm can identify the temperature loss and alert the farmer as necessary. Expanding the research area, and study period, and investigating alternative methods of a more cost-effective hydroponic farming system, farmers allow to innovate in the farming system at a lower cost to produce high-quality crops.

Acknowledgments

We express our gratitude to the editor and reviewers for their valuable feedback on the manuscript.

Conflict of interest

The authors declare no conflict of interest.

Contribution of the authors

Writing of the manuscript: SD and BM; Correction of the manuscript: AS and SD.