Influence of Sulphur and Plant Growth Regulators on Nutrient Concentration and Available Soil Nutrient Status in Summer Groundnut (Arachis hypogaea L.)

A field experiment entitled “Effect of sulphur and plant growth regulators on nutrient concentration and available soil nutrient status in summer groundnut (Arachis hypogaea L.).” was carried out under irrigated sulphur deficient conditions in medium black clayey soil during summer 2014 at Junagadh (Gujarat). The experiment consisting of 20 treatment combinations, comprising 4 levels of sulphur (0, 20, 40 and 60 kg S ha⁻¹) and 5 levels of plant growth regulators {Control (water spray), NAA @ 40 ppm at 25 DAS, GA₃@ 20 ppm at 25 DAS, NAA @ 40 ppm twice at 25 and 50 DAS and GA₃ @ 20 ppm twice at 25 and 50 DAS}. These treatments were evaluated under factorial randomized block design with 3 replications. Results indicated that sulphur application up to 40 kg ha⁻¹ significantly increased N, P and S concentrations in pods and haulm of groundnut except N concentration in pods and S concentration in haulm where significant response was obtained only up to 20 kg S ha⁻¹. A significant improvement in available nitrogen, phosphorus and sulphur status in soil was observed after harvest of crop due to application of sulphur up to 40 kg ha⁻¹ except available nitrogen which was at par with 20 kg S ha⁻¹. Application of GA₃ @ 20 ppm twice at 25 and 50 DAS recorded the maximum nitrogen, phosphorus and sulphur concentrations in both pod as well as haulm in groundnut, available P and S status over rest of the treatments and was closely followed by foliar spray of NAA @ 40 ppm twice at 25 and 50 DAS.