Application of highly sustainable and productive inputs is required to increase food production in order to feed the growing world population while using the same amount of land. Thus, in its very first attempt, the Tamil Nadu Agricultural University (TNAU), Coimbatore, Tamil Nadu, has produced water soluble fertilisers (WSF) named as TNAU-Water Soluble Fertilizers (TNAU-WSF), and it is necessary to optimise on various crops. One of the most essential vegetables in Indian cuisine is the small onion, which has a high demand but a low productivity. The use of TNAU-WSF was initiated to improve small onion crop productivity and quality. Eight treatments were incorporated in a field experiment that was set up using a Randomised Block Design (RBD), including soil test-based applications (STB) of 75%, 100%, and 125% NPK ha-1 as TNAU-WSF, with and without sulphur (S) and TNAU liquid multi micronutrient (TNAU LMM) and the absolute control. With small onion (CO 4), each treatment was replicated three times. Soil test based application at higher nutrient level (125% NPK) recorded higher nutrient availability, plant nutrient content and enhanced bulb quality (crude protein and total sugars) of small onion. The correlation study revealed that treatments with higher nutrient availability had a high impact on nutrient content and bulb quality of small onion.

Enhancing the food production for the growing world population has needed application of highly sustainable and efficient inputs to produce more food per unit of land. Hence, Tamil Nadu Agricultural University (TNAU), Coimbatore, Tamil Nadu has produced Water soluble fertilizers (WSF) in its maiden attempt and it is necessary to optimize on different crops. Small onion is one of the most important vegetables in the Indian diet and it has high demand but low productivity. To enhance crop productivity and quality of small onions, the application of TNAU-WSF was taken up. A field experiment was laid out in a Randomized block design (RBD) incorporating 8 treatments comprising of application of RDF at100% NPK as TNAU WSF, soil test based application of 75%, 100%, 125% NPK ha-1 as TNAU-WSF with soil application of sulphur (S) and foliar spray of TNAU Liquid multi micronutrient (LMM) and without S and TNAU LMM and absolute control. Each treatment was replicated thrice with onion (CO 4). Soil test based application of 125% NPK ha-1 as TNAU-WSF with sulphur (S) and TNAU LMM recorded significantly higher in plant height (54.01 cm), the number of leaves per bulb (8.56), leaf greenness (67.5 SPAD), root length (5.42 cm), polar bulb diameter (4.38 cm), equatorial bulb diameter (2.72 cm) fresh bulb weight (74.21 g), bulb yield (1751 t ha-1) and quality attributes like total soluble solids (TSS) (14.78 °Brix), ascorbic acid content (15.34 mg 100 g-1), pyruvic acid content (2.27 µmol g-1). However, soil test based application of 100% NPK ha-1 as TNAU-WSF was found to be an ideal rate to attain the economic target yield of the onion crop.

To achieve sustainability in agricultural crop production, water-soluble fertilizers were produced around the world. With this view, Tamil Nadu Agricultural University, Coimbatore, has produced TNAU-Water Soluble Fertilizers (TNAU-WSF). The field experiment was carried out in the farmer’s field at Devarayapuram, Coimbatore, to assess the effect of newly synthesized TNAU-Water Soluble Fertilizers (TNAU-WSF) on nutrient uptake and nutrient use efficiencies of  small onions. The experiment was conducted in Randomized block design (RBD), which includes eight treatments of different nutrient levels of soil test based application from 125%, 100% and 75% NPK as TNAU-WSF with sulphur and TNAU Multi Micronutrient (TNAU-LMM). The results were obtained as the soil test based application of 125% NPK as TNAU-WSF with sulphur and TNAU-LMM recorded higher nutrient uptake (N, P, K, and micronutrients) and nutrient use efficiencies (agronomic efficiency and apparent nutrient use efficiency) compared to other nutrient levels (100% and 75%).