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ABSTRACT

Soilless farming is an emerging concept towards smart agriculture, which refers to the efficient management of agricultural farms using modern information and communication technologies to increase the quantity and quality of agricultural produce while reducing the human labor required. It is helping to grow pesticide free vegetables, herbs and flowers indoors in urban and sub-urban areas without soil. In this article an attempt has been made to make farmers aware of adopting this farming technique by giving a detailed description of development, different types, opportunities and challenges of soilless farming.

Keywords: Soilless farming, Smart Agriculture, Information and Communication, Pesticide free vegetables

Smart agriculture refers to the concept of agricultural management that uses modern technologies such as Internet of Things (IoT), soil scanning, automated sensor based irrigation, soilless farming with the aim of enhancing the quality and quantity of agricultural produces. It is such a meaningful effort towards a bright future with the introduction of better agricultural technologies, with objective to cost effective, better efficiency, quality and higher productions. Basically, soilless farming refers to growing a wide range of horticultural crops in various pots, containers, pipes and trays with various growing mediums or substrates contained inside grow bags such as vermiculite, rock wool, and coconut fiber or coco pit.

History of Soilless farming

Soilless farming technology was developed by German botanists Julius von Sachs and Wilhelm Knopp during the period 1859 to 1875. In India, it was started in the year 1946 by an English scientist WJ Shal to Douglas. He set up a laboratory in the Kalimpong area of ​​West Bengal and wrote a book on hydroponics called Hydroponics - The Bengal System.

This farming approach is technically feasible because soil is not addressed in the photosynthesis process. Under this technology, we can monitor the daily needs of our farms as well as fertilizers and pesticides use. In the present scenario, soilless farming is emerging as a promising alternative towards smart agriculture. As we know, soil is a medium commonly used for growing plants, which provides the support, nutrition, air and water needed for optimum growth of flora and fauna. But in recent time, due to the soil borne diseases, nematodes, drainage and other soil borne factors, this farming technology is proven to be very useful. Apart from it, it has also emerged as a promising alternative to resolve some serious challenges that affect crop production such as climate change, paucity of arable land, reduced per capita availability of water and food, etc. Furthermore, soilless culture is becoming increasingly popular as a technology and has become an alternative to poor soil health and abundant recurrent soil-borne diseases sites. In case of protected farming, continuous crop production results high soil salinity, damage soil structure as well as increase in pH and electrical conductivity (EC). Therefore, this technique is very useful in protected farming.

Globally, Methyl bromide is the most effective fumigant being used for soil treatment and it has been proved that it is damaging the atmosphere`s vital ozone layer. Therefore, most countries have banned methyl bromide application for soil treatment. Under soilless farming this types of chemical is not applied for soil amendments.

In India, for the promotion of soilless farming technology, the central and state governments have subsidized the capital cost for farmers willing to spend on soilless farming (hydroponics).Maharashtra government has provided 50% subsidy for adopting soilless farming (hydroponics) technology for growing animal feed (Daga, 2020).

Similarly, a separate subsidy has been prepared by the National Horticulture Board (NHB) for each state of the country. The average yield of lettuce was also recorded between 9-10 tonnes per acre per year and 300-400 tonnes per acre per year under soil based agriculture and hydroponics agriculture, respectively (Anonymous, 2021)

Advantages and limitations of soilless farming

It is a feasible option for efficient use of land and water resource. In urban and peri-urban areas where arable land is polluted, its importance increases. According to the Food and Agriculture Organization (FAO), under soilless systems, vegetable production increases about 20–25% than conventional systems. But due to higher input cost, it is limited only to high value crops. It also required utmost care with regard to plant health, environment control and irrigation management. The benefits and limitations of soilless farming are shown in Figure 1 and 2.

Classification of soilless farming

It is classified into four types such as solid media culture, hydroponics, aeroponics and aquaponics, based on the type of substrates and containers, the nutrient system for the plant and drainage (Figure 3a and 3b).

In solid media culture, coco-peat, pearlite, vermiculite, vermicompost, gravel, tur, rockwool, saw dust, coconut fiber and peat moss are commonly used. These are mainly four types such as Trench or Trough Technique, Hanging Bag Technique, Pot Technique and Grow Bag Technique. Apart from it, in hydroponics, plants are grown in liquid medium contained in a pipe or container, which has two types of circulating and non-circulating systems.

In case of circulating,  the nutrient solution moves around the root zone of the plant and is collected, replenished and reused as per the requirement, which are mainly of Deep flow technique (DFT) and Nutrient Flow Technique (NFT) types whereas non-circulating system is a system in which the nutrient solution is not circulated but is used only once. These are mainly of three types such as capillary action, root deeping and floating technique. In Aeroponics, the nutrient solution is sprayed every 2-3 minutes for a few seconds by hanging the roots of the plant in the air suspended in the holes of the styrofoam panels and also properly watered and aerated as needed.It is found suitable for growing leafy vegetables such as spinach, lettuce, etc. inside protected structures. In this, double crops can be grown by efficient technology. However, Aquaponics is a type of aquaculture, in which fish and other aquatic animals and plants are easily grown using hydroponics method. In this system, fish feces replenish the organic manure of the plants and the plants purify water for fish. The detailed classification of soilless farming is shown in Figure 3.

Strategies for irrigation scheduling and fertigation

Drip irrigation systems are best suited for timely water and nutrients application to crops grown in soilless media, especially in-line and stack drippers. In it, low volume high frequency irrigation is more popular. Irrigation and fertigation scheduling is very sensitive to horticultural crop and therefore appropriate fertigation management is essential. For growth of vegetables and flowers on sand dunes in greenhouse and in dormant substrates, there should be special and precise control of fertigation as inert media have very low cation exchange capacity and therefore do not provide nutrients. Fertigation is the only source of nutrients in soilless system. In soilless system for fertigation, it is recommended to use at least two tanks (A and B) for stock solution due to discrepancy problem between different water soluble fertilizers. Tank A should contain calcium and magnesium related fertilizers and tank B should contain phosphorus and sulfur related fertilizers. Nitrogen and potassium fertilizers can be used in both tanks, while chelated micronutrients should be part of tank B. The stock material is taken from both the tanks and mixed with irrigation water usually 1-3 liters of concentrate mixed with 1000 liters of normal irrigation water to prepare the solution (Hassan et al., 2018).

Recent advances in irrigation scheduling and fertigation

Nowadays, automatic irrigation is being popularized for soilless farming, in which farming community can control and operate the whole soilless system from their homes using digital mode such as mobile.In it, with the help of soil, pH and temperature sensors using the IoT, they provide suitable environment to crops and they get rid of the dependency of the crops on the weather, as well as also increase the productivity. In this context, recently C—DAC has also developed automated hydroponics system (Figure 4).

It is a closed loop control system in which a calculated flow of water and nutrients is carried out in a five layer mixing tank. The solution is pumped into a pipe tube, where the plants are grown with a suitable supporting cup. Plant roots directly absorb water and nutrients. The overflow solution is collected in the recycle tank and pumped back to the mixing tank for reuse. The automation system enables for easy graphical user interface (GUI) based programmable timing control and another monitoring system for simultaneous control of the temperature, pH and EC of the solution.

 Case study of soilless farming

There have been successful applications of soilless farming on a global scale, for example in Tokyo, where the growing population has made land extremely valuable and has turned to hydroponic rice production (Feltman, R., 2013). Rice is successfully grown in underground vaults without the use of soil. Not only are these, instead of the traditional single crop, four crop rotations being grown annually. Hydroponics has also been used successfully in Israel, which has a dry climate. In this country, a company “Organitech” uses hydroponic systems to grow large quantities of berries, citrus fruits, and bananas in 40 foot long shipping containers that could not be grown in the climate here. It is found that this advance technology produce 1,000 times higher yield in the same size area of ​​production (Dholwaniet al., 2018). India is not an exception and the Defense Bio-Energy Research Institute, Haldwani has successfully developed a hydroponics system combining soilless farming with rainwater harvesting techniques in Himalayan regions (Pant et al., 2018). The experience has been gained in successful cultivation of various crops in hydroponics system using single nutrient solution at different altitudes and also developed suitable nutrient schedule for broad range of vegetables. Apart from this, now many large cities of country are turning towards soilless farming and are making a unique contribution towards smart agriculture. Large number of startups of the country like Aqua farms, Letcetra Agritech etc. are also actively participating in increasing its popularity (Wangchuk, R.N., 2019) and few important startups shown in Figure 5.

Conclusion

Soilless farming can play a magnificent role in producing green, healthy and safe horticulture produce throughout the year. However, gap of technical knowledge, systematic protocols, procedures and input management are some of the major constraints in the expansion and popularity of this technology. Yet, its technological benefits are encouraging growers and professionals to start soilless farming with investments in kitchen gardens, terraces, balconies and farms. The initial cost in adopting this technology is high, but off-season farming is a better viable option for more earning and fresh vegetables and flowers supply in urban areas. It is fast catching up technology not only among progressive producers but also among urban and peri-urban households and is a commendable and worthwhile effort towards smart agriculture.

References

Anonymous.2021. https://www.datamintelligence.com/research-report/india-hydroponics-market

Daga, A. (2020). Hydroponic Farming & Subsidy. Available at:https://finraja.com/hydroponic-farming-subsidy/uncategorized/

Dholwani, S. J., Marwadi, S. G., Patel, V. P., & Desai, V. P. (2018). Introduction of Hydroponic system and it’s Methods. Inte. Jour. for Rese. Tren. andInno, 3(3), 69-73.

Feltman, R., (2013) Available link: https://qz.com/115226/photos-the-nine-story-tokyo-office-building-thats-also-a-farm/

Hasan, M., Sabir, N., Singh, A. K., Singh, M. C., Patel, N., Khanna, M., &Pragnya, P. (2018). Hydroponics Technology for Horticultural Crops. Tech. Bull. TB-ICN, 188(2018), 30.

https://www.cdac.in/index.aspx?id=pe_aee_AutomatedHydroponicsSystems

Pant, T., Agarwal, A., Bhoj, A. S., Joshi, R. P., Prakash, O., &Dwivedi, S. K. (2018). Vegetable cultivation under hydroponics in Himalayas: Challenges and opportunities. Def. Life Sci. J, 3, 111-119.

Wangchuk, R.N. (2019). Eight Hydroponics Startups Helping Urban Indians Grow Their Own Food! Available link:https://www.thebetterindia.com/195582/hydroponics-startup-grow-vegetables-home-hyderabad-bengaluru-delhi-india/

 

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