Assessment of Nitrogen and Sulphur Nutrition to Optimize the Yield and Quality of Groundnut (Arachis hypogaea L.)

A field experiment was conducted during February 2023 to June 2023 at Kerala Agricultural University, College of Agriculture, Padannakkad, Kasargod with the objective of formulating a nutrient schedule for groundnut, consisting different sources of nutrients (especially nitrogen and sulphur), time and method of application. The experiment was laid out in randomized block design with 9 treatment combinations of 2 factors, viz., Nutrient Schedule (S) and Foliar Nutrition (F), with 3 treatments each, viz., S1: nitrogen (10 kg ha-1) and sulphur (20 kg ha-1) as per package of practices as basal, S2: nitrogen and sulphur each @ 10 kg ha-1 in 2 equal splits (one as basal and the other at 20 days after sowing), S3: control (without nitrogen and sulphur), F1: foliar application of urea and potassium sulphate @ 1% each at 10 and 30 days after sowing, F2: foliar application of nano urea @ 3 ml 1-1 and nano sulphur @ 1 ml 1-1 each at 10 and 30 days after sowing, F3: control (without foliar application). The main effects of the treatments were significant with S1 recording taller plants at 20 (8.16 cm), 40 (18.05 cm) and 60 (30.34 cm) days after sowing and S2 at 80 days after sowing (37.61 cm). Foliar nutrition was found effective with application of nano fertilisers (F2), recording 11.17%, 27.02% and 18.75% taller plants than control at 40, 60 and 80 days respectively after sowing. The treatment combination S1F2 recorded the tallest plants at different growth stages with heights 18.61 cm, 34.50 cm and 41.50 cm respectively at 40, 60 and 80 days after sowing. The leaf area of groundnut varied significantly with treatments and their combinations. Application of nitrogen and sulphur @ 10 kg ha-1 each in 2 splits (S2) was superior to other treatments in recording higher leaf areas at 40, 60 and 80 days after sowing with respective values of 747.16 cm2, 1435.60 cm2 and 1216.20 cm2. Foliar nutrition with conventional urea and potassium sulphate (F1) recorded significantly higher leaf area at 40 (734.87 cm2) and 60 (1382.70 cm2) days after sowing and it was at par with foliar application of nano fertilisers (F2) at 40 days after sowing (716.70 cm2). Application of nitrogen and sulphur in 2 splits and foliar spray of nano urea and nano sulphur (S2F2) recorded maximum leaf area at 60 (1543.83 cm2) and 80 (1341.51 cm2) days after sowing. The plants which received nitrogen and sulphur in two equal splits (S2) and foliar application of nano urea and nano sulphur (F2) or their combination (S2F2) were superior in terms of kernel yield of groundnut with values 1925.87 kg ha-1, 1801.70 kg ha-1 and 2109.80 kg ha-1 respectively. The highest oil content was obtained with the treatment S2 (48.01 %) and it was on par with S1 (47.73 %). The effect of foliar nutrition was also significant and the treatments F2 and F1 were on par and they recorded 48.04 % and 47.81 %, respectively. Integrated application of nitrogen and sulphur each @10 kg ha-1as basal and foliar spray of nano fertilisers (S1F2) recorded the highest (49.30 %) oil content and it was on par with S2F1 (49.10 %) and S2F2 (48.4 %).