Terrestrial farming, a traditional agriculture practice is based on the use of soil as a medium to grow plants. Soil provides essential nutrients, retains water, helps in aeration, and provides anchorage to the plant for successful growth. At the same time, it also provides habitat to numerous microorganisms living close to the vicinity of plants. Often, disease-causing microorganisms pose threats to the plants, resulting in stunted growth. In India, the livelihood of around 50 per cent of the population depends upon agriculture, which accounts for 12 per cent of the national GDP . In the era of industrialization, urbanization, and rise in the human population, a country like India is facing a decline in per capita hectare of agricultural land. Additionally, agricultural practices in India are hampered with over-fertilization, poor irrigation methods, excessive use of pesticides, and unpredictable seasonality; which either reduce the land productivity or contaminate the harvest.
Over the centuries, humans have evolved with innovative technological solutions to the given contemporary problems. For example, the case of permaculture in Dead Sea Valley, Jordan and the expansion of agricultural farms on barren lands in Leh-Ladakh. The Fourth Industrial Revolution includes hydroponics as an industry and projects it to be the neo-Malthusian solution to the global population rise. In cities, where the conglomeration of cemented structures shelters the massive human populations disconnect the human population from agriculture practices, which cause several tangible and intangible costs. In hydroponics, plants can be grown without using soil under controlled conditions like maintaining air and root temperature, availability of light, water, and nutrients. A square meter area could be converted into multiple acres through vertical farming. From a conservative point of view, this technique reduces water usage by half as compared to soil cultivation . In urban areas, where there is a scarcity of space, hydroponics enables people to grow vegetables and herbs in their houses and over their rooftops. Thus, urban areas can be the next agricultural grounds.
Figure 1. Basic Hydroponics assembly
However, the hydroponics technique has its own limitations such as maintenance of pH levels (5.5 to 6.5), monitoring of nutrient supplies, etc. Below or above this range of pH reduces the availability of essential nutrients required by plants. Hence, expertise in the technique and sophisticated instruments is required. Nutrient availability can also be a limiting factor. Depending on the availability, people can utilize metabolic waste of bats, birds and fishes in the mixture of nutrient solution. But, again, careful handling of excreta is required otherwise the collection and use of metabolic waste can cause several unknown diseases . In order to grow the non-seasonal varieties of crops in a greenhouse environment, proper attention is required to maximize yield and to control plant diseases. In the absence of pollinators in this system, manual pollination may be required and thus, again requires scientific knowledge and skills. Globally, this model of agriculture has been imagined in the form of skyscrapers of crops standing within cities (For e.g., University of Arizona’s Controlled Environment Agriculture Centre, run by Gene Giacomelli) . However, in the local context of India, there can be several other challenges and limitations. For example, the huge dependency of farmers on cities, affordability of hydroponics models (even within cities), insufficiency and inefficiency of water treatment plants in cities, development status of the country, psychological scepticism, etc.
Our ancestors took thousands of year in optimizing the productivity of soil through several practices. The present agricultural practices largely depend on fertilizers, microorganisms, manure, vermicomposting, etc. As of now, we imagine hydroponics as a practice of preparation for the contingent global food insecurity. Presently and practically, in the short term, we think that the hydroponics setup can be installed either on river banks or in peripheries of cities. Within cities, the model can be promoted at an individual level or in the form of public vertical gardens. The public vertical gardens are possible through state-sponsored programs using rooftops of public buildings like schools, hospitals, government offices, abandoned private properties or bare governmental lands, etc. Above all, the hydroponics model at least present aesthetic value to the urban life which connect it to the natural processes. We assume many children in cities find it difficult to understand from where a tomato or a carrot comes! Although hydroponics is still an evolving science, lots of optimization and governmental support is required for the success of this technology. In the past, the hydroponic models have failed to encourage the general public, but still, it may be used as a reference point to start with . Who knows, the next Antilia is not a residential but a commercial agricultural setup using hydroponics!
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