Hydroponic crops can be grown using a variety of media and production systems (NFT system, wick system, drip system, ebb flow system etc.). EC and pH management are required to successfully handle these hydroponic systems (water quality and nutrient solution maintenance). These hydroponics systems have gained rapid adoption due to disciplined management of their resources and food production. Although the hydroponic system was developed in a closed-loop system, and substrate nutrition increases production, it is not cost-effective to develop this system on big scale. It is critical to design a low-cost hydroponic structure that decreases reliance on human labour and lowers overall startup cost in order to increase the commercialization of hydroponic farms. We need more research to develop more productive and cost-effective organic nutrient solutions and improve hydroponic crop production systems. In this review paper, we will discuss the opportunity and challenges in hydroponic crop production systems.

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Agrochemicals which ushered in the 'green revolution' in the 1950-60's, boosted food productivity, but at the cost of environment and society. It increased food production but also destroyed the 'physical, chemical and the biological properties' of soil over the years of use. It killed the beneficial soil organisms and also impaired the power of 'biological resistance' in crops making them more susceptible to pests and diseases. No farmland of world is free of toxic pesticides today. Over the years it has worked like a 'slow poison' for the soil and society. According to UNEP and WHO nearly 3 million people suffer from 'acute pesticide poisoning' and some 10 to 20 thousand people die every year from it in both the developed and the developing countries. Organic farming by earthworms (Sir Charles Darwin's 'friends of farmers') can provide a sustainable and also highly economical solution to the various problems created by the destructive agrochemicals in farm production. Earthworms vermicompost are scientifically proving to be an 'extraordinary powerful growth promoters and protectors' for crops (5-7 times over other bulky organic fertilizers and 20-40 % higher over chemical fertilizers). They are rich in NKP, micronutrients, beneficial soil microbes like 'nitrogen-fixing' and 'phosphate solubilizing' bacteria, 'mycorrhizal fungi', humus and growth hormonesauxins, gibberlins and cytokinins. It has very high 'porosity ', 'aeration', 'drainage' and 'water

Fourteen genotypes of tomato collected from different sources were evaluated inside naturally ventilated polyhouse at Polyhouse Complex, Department of Horticulture (Vegetable and floriculture), BAU, Sabour, Bhagalpur during 2018-2019. The experiment was laid out in RBD with three replications. Data from analysis of variance depicted that mean sum of squares of all genotypes were highly significant for all traits under study except titratable acidity and β-carotene which indicated the existence of ample genetic variability among the genotypes. Genotype NS 4266 had least days to first flowering, days fifty percent flowering, lowest number of locules, highest plant height at 60 DAT along with maximum β- carotene & lycopene content; TODINDVAR-8 had lowest number of nodes to first flower and maximum average fruit weight; Palam Tomato Hybrid-1 displayed maximum no. of flower per truss; Heemshikhar had lowest no. of days to first fruiting; TODINDVAR-5 had highest no. of fruit per truss; Arka Abha showed earliest days to first picking; San Marzano had maximum polar diameter and plant height at final stage of harvesting; TODINDVAR-6 show maximum equatorial diameter and lowest titratable acidity; Arka Samrat had maximum pericarp thickness; Hawaii 7998 was observed with maximum no. of fruit per plant; Arka Vikas had maximum TSS content. However, Pant Polyhouse Tomato-2 contained maximum ascorbic acid. Different types of fruit shapes viz. flat round, oval, round, heart shaped, cylindrical and fruit colour viz. red, pink, yellow-orange was exhibited by various genotypes. All the genotype displayed the absence of green shoulder on fruit except San Marzano. Three genotypes namely Palam Tomato Hybrid-1 (5.72 kg/plant), Heemshikhar (4.85 kg/plant) and NS 4266 (4.82 kg/plant) was identified for higher yield among all the genotypes.

A field experiment was conducted during rabi season at Trihut college of Agriculture Dholi, Muzaffarpur to evaluate the response of sources (Elemental sulphur and gypsum) and different doses (15, 30 and 45 kg S ha-1) of sulphur growth yield and quality of onion. Bulb yield, nutrient content in onion and nutrient uptake were significantly improved by the application of sulphur by gypsum over elenmental sulphur. Amongst sulphur doses, the application of sulphur at 40 kg/ha showed significant superiority over others, however it was at par to sulphur at 30 kg/ha.