Effect of Different Rate and Time of Application of Slag based Gypsum on Nutrient Use Efficiency, Quality and Yield of Groundnut

Background: Slag based gypsum (SBG) is a value-added product of iron and steel industry. Application of gypsum as source of calcium and sulphur for groundnut cultivation is common practice and mainly applied during peg initiation stage of groundnut. However, its effect is mainly influenced by the type of soil and dissolution of gypsum, which facilitates the yield and quality of groundnut. Hence, field experiments were conducted to know the effect of application of different rates of SBG as basal and split application on soil properties, yield, quality, nutrient use and uptake efficiency of groundnut in acidic soil. Methods: This study contains of seven treatments which includes recommended dose of fertilizer (RDF) with three levels of SBG (375, 500 and 625 kg ha-1) was applied as basal and split and 500 kg natural gypsum (NG) ha-1 was applied as basal dose according to package of practice (POP) of University of Agricultural Sciences, Bangalore by using randomly complete block design (RCBD) at Agricultural Research Station, Balajigapade during kharif 2018 and 2019. Result: The pooled data of two field experiments on groundnut revealed that application of RDF + 625 kg SBG ha-1 as 50% at sowing + 50% at peg initiation stage recorded higher pod (28.01 q ha-1), haulm (54.46 q ha-1), kernel (20.59 q ha-1), protein (89.70 q ha-1) and oil (7.06 q ha-1) yield when compared to other treatments. There was an increase in pod, haulm and oil yield of groundnut by 11.62, 20.59 and 17.99%, respectively with the split application of 625 kg SBG ha-1 (50% at sowing + 50% at 30 DAS) over NG applied treatments. Split application of SBG significantly increased the availability of nutrients in post harvest soils than basal application. Significantly higher S and Ca nutrient use efficiency (33.98 and 28.93 kg produce/kg S and Ca utilized, respectively) and uptake efficiency (0.39 and 1.29 kg kg-1, respectively) was recorded with the split application of SBG @ 375 kg ha-1.