Integrated Nutrient Management in Onion-A Review

Abstract

Onion (Allium cepa L.) is a bulbous vegetable crop and cultivated in many parts of the world. Onion is majorly used in our daily diet for its nutritional value. In onions, sulfur-containing compounds and allinase enzymes are responsible for their lachrymatory effect and pungency. Flavanoid compounds in onions like kampeferol and quercitin show anti-inflammatory and antioxidant properties. Globally, India stands second in onion production, book keeping for 10 % of total production from 16 % of total area. As per FAO data (2012), China leads the world in production (20.5 million tonnes), followed by India (13.3 million tonnes). Maharashtra, Madhya Pradesh, Karnataka, Rajasthan, Bihar, Gujarat, Andhra Pradesh, Haryana, West Bengal, Gujarat, and Uttar Pradesh are the top onion-producing states in the country, contributing nearly 90% of the country’s overall onion production. Maharashtra stands first in production with 8,854.09 thousand tonnes with 38.09 percent share, followed by Madhya Pradesh (15.92 percent share) and Karnataka (12.85 percent share) (https://agriexchange.apeda.gov.in). Onion is a nutrient-sensitive crop and the nutrient requirement varies with cultivar, location, and season. Fertilizer recommendation for onion crop is 100-150 kg N, 40-80 kg P2 O5, and 0-125 kg K2 O per hectare (Source: NHB). Many studies have reported that 2.1 kg N, 0.75 kg P2 O5 , 2.2 K2 O, and 0.28 kg S per hectare of nutrients are removed by onion crop to produce a bulb yield of 1 ton (DOGR, 2015). Use of synthetic fertilizers alone causes leaching, increases toxicity, and degrades the soil environment. A Study by Kwaghe et al. (2017) have shown that nutrient uptake by the onion crop enhanced to 0.76, 43.82, and 2.42 kg/ha by the combination of both organic and inorganic fertilizers, thereby increasing the crop yield. Therefore, a rising need exists to provide an adequate and balanced nutrient application for attaining good crop yield and quality without affecting soil fertility status. This INM based approach for nutrient management has a positive impact on plant growth, agricultural sustainability, and fertility of soil. Hence to enhance soil fertility and to improve the nutrient uptake, the concept of Integrated Nutrient Management (INM) could be adopted.