Annunciating the Present Context and Future Directions of Soilless Cultivation of Horticultural Crops for a Sustainable Agriculture

The world is facing threats such as the shrinkage of farmlands, an ever-increasing population, and the looming vulnerability of the climate, all of which warrant alterating of traditional agricultural practices to ensure food and nutritional security. Crop cultivation, especially of horticultural crops, which are highly dependent on ecology, is mostly affected by climatic factors. Furthermore, rapid urbanisation has boosted crop diversification, and several exotic and off-season crops are now available in the market that cannot be grown traditionally. Under these contexts, the age-old method of soil-based cultivation may not fit the growing demands. To address these pressing issues and natural vagaries, soilless cultivation (SLC) practices are gaining pace. Among SLC, hydroponics, aquaponics, aeroponics and vertical farming in soilless media have become popular in recent years. SLC is well-suited for growing green leafy vegetables and herbs, annual and high-value crops, such as strawberries, saffron, etc. Hydroponics is the practice of growing plants in a nutrient-rich water solution that offers control over environmental variables and enhances input use efficiency, yield and quality. Aeroponics is an advanced version of hydroponics where nutrient-rich mist is sprayed intermittently onto roots suspended in the air. Aeroponics reduces water and nutrient usage and enhances crop growth. Aquaponics is a synergistic integration of hydroponics and aquaculture, which combines SLC and fish farming in a closed loop. All SLC techniques offer a paradigm shift from traditional farming to resource-efficient and climate-resilient crop cultivation practices that enable high-quality farm produce. Crops are prone to various pests and diseases in orthodox cultivation practices; whereas SLC reduces the risks of abiotic and biotic stresses and thus reduces the possibility of pesticide residue in the harvested crops. Recent developments in digital agriculture have provided ample scope for the adoption of artificial intelligence, machine learning and the Internet of Things for automation, where a congenial microclimate can be created under controlled environment conditions with precision input management. Under these circumstances, it is observed that current agriculture has welcomed such a transformation of farming techniques in urban and peri-urban areas, aligning with the Development Goals (SDGs), which will further expand its arena. The chapter focuses on the methodology of SLC practices, their pros and cons, and future perspectives.