176 Indian Journal of Agricultural Sciences 89 (11): 1928–31, November 2019/Article Establishing critical limits of sulphur for groundnut (Arachis hypogaea) RAHUL KUMAR 1 , G C HAZRA 2 , RUMA DAS 3 , S P MAJUMDER 4 , DHANESHWAR PADHAN 5 and A C DAS 6 Bidhan Chandra Krishi Viswavidyalaya, West Bengal 741 252, India Received: 23 March 2019; Accepted: 22 April 2019 ABSTRACT Sulphur is essential for growth and development of groundnut (Arachis hypogaea L.). Defciency of S is widespread in soils of India, and is becoming a major concern for the quality and yield of groundnut crop. Therefore, a study was conducted to investigate the response of groundnut to S application in alluvial Inceptisols of West Bengal with four levels of S, i.e. 0, 15, 30 and 45 kg/ha. The critical limits of Sulphur in soil and plant for defciency, adequacy and toxicity were determined from Bray percent yield (BPY). The amount of CaCl 2 extractable S in soils varied from11.90–29.17 mg/kg while the critical level for defciency of S in groundnut was graphically 18.6 mg/kg and statistically 19.58 mg/kg in soils. Application of S increased groundnut yield signifcantly, concentration of S in plant and its uptake by groundnut parts. The critical limit was determined to be 3.0 g/kg for groundnut plants and 4.42 g/ kg for groundnut nuts at harvest. Key words: Critical limit, Groundnut, Inceptisols, S uptake Present address: 1 Senior Research Fellow (rahulyadkumar@ gmail.com), 3 Scientist (rumadas13@gmail.com), Division of SSAC, ICAR-IARI; 2,6 Professor (gchazra@rediffmail.com, acdas2@rediffmail.com), 4,5 Research Scholar (sp_mjmdr@ rediffmail.com, dhaneshwar.padhan@gmail.com), Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya. Sulphur is a structural constituent of organic compounds, some of which are uniquely synthesized by plants, providing human and animals with essential amino acids (methionine and cysteine). Sulphur involved in chlorophyll formation, activation of enzymes and is a part of vitamins such as biotin and thiamine (B1) (Hegde and Sudhakarababu 2007). It is a master nutrient for oilseed production as each unit of fertilizer S generates 3-5 units of edible oil (Ramdevputra et al. 2010). Role of S in Indian agriculture is now gaining importance because of the recognition of its role in increasing crop production, not only of oilseeds, pulses, legumes and forages but also of many cereals (Singh et al. 2000). Sulphur defciency is extensive particularly in the areas where crop is intensively cultivated with the use of S free fertilizers (Basak et al. 2002). At present, defciency in soils of various Indian states varies from 5–83% with an overall mean of 41% (Singh 2001). Groundnut (Arachis hypogaea L.) is one of the most important oilseed crops of India occupying 2/3rd area under oilseeds. The high-energy value, protein content and minerals make groundnut a rich source of nutrition at a comparatively affordable price. Besides, it’s a valuable source of vitamins E, K and B. It is the richest plant source of thiamine and is also rich in niacin, which is low in cereals. The groundnut grown on light textured soils generally suffers from S defciency due to leaching of sulphate. The crop responds signifcantly to the application of S in the light textured soil (Giri et al. 2014). Because of the increasing area under groundnut cultivation and emerging S defciency, judicious application of S fertilizer is required. To attend to this issue, it is important to evaluate the critical concentration of this nutrient in soils and plants for optimum crop nutrition. In this context, the present investigation was done to study the response of groundnut to different rates of S application and to establish the critical limit of sulphur in soils as well as in plants in alluvial Inceptisols of West Bengal. MATERIALS AND METHODS Twenty surface soil samples (0-15cm) were collected from different locations of seven districts (Coochbehar, Jalpaiguri, Uttar Dinajpur, Burdhawan, Bankura, Hoogly and Nadia) under the different agroclimatic zones of West Bengal, India during 2016. Samples were air-dried, ground and passed through a 2 mm nylon sieve. The soil samples were analyzed for pH (Jackson 1973), clay content (Bouyoucos 1962) and organic carbon (Walkley and Black 1934), Available S (Chesin and Yien 1951). A pot culture experiment was conducted on smaples collected from twenty different locations at Central Research Farm, BCKV, Gayeshpur (Latitude 22°58’ º N, Longitude 88°29’E, Altitude 9.75 m amsl) using groundnut as test crop during 2016. Ten kg of soil was transferred into each pot. Recommended doses of N, P 2 O 5 and K 2 O @20, 60 and 60 kg/ha, were applied as Urea, SSP and KCl respectively. The N was https://doi.org/10.56093/ijas.v89i11.95345