Background

• Crops require the right mix of three nutrients viz. nitrogen, phosphorus, and potassium or NPK (N helps in plant growth and development, P not only accelerates blooming and the growth of roots but also helps plants to withstand stress and K helps the process of photosynthesis and is essential to plant growth). 
• Imbalanced use of N, P and K leads to the loss of fertility of the soil over a period of time, which affects efficiency of fertilizer use and crop productivity. 
• In India, urea, a nitrogen-based fertilizer, is the most commonly used fertiliser because it is highly subsidised. The overuse of nitrogenous fertilizers has led to an imbalanced fertilizer application in the country, heavily skewed toward nitrogen. 
• This imbalance has resulted in an abnormally high NPK ratio of 10.9:4.9:1 against the recommended ratio of 4:2:1. 
• This imbalance causes problems, right from stagnating or declining productivity to soil sickness, widespread deficiency of secondary nutrients and micronutrients, and soil alkalinity and salinity. 
• Eventually, it results in reduced efficiency of fertilizers, low yields and low profitability for farmers.

About NBS Scheme

• In order to promote balanced fertilization of soil, Nutrient Based Subsidy (NBS) programme for fertilizer was initiated in 2010. 
• Under the scheme, a fixed amount of subsidy decided on an annual basis is provided on each grade of subsidized Phosphatic and Potassic (P&K) fertilizers based on its nutrient content. 
• The scheme aims at ensuring balanced nutrient application to the soil.
• It also aims at improving agricultural productivity and promoting the growth of the indigenous fertilizers industry.
• The scheme is being implemented by the Department of Fertilizers under the Ministry of Chemicals and Fertilizers.

https://pib.gov.in/PressReleasePage.aspx?PRID=2079052