Optimization of nitrogen and potassium Fertigation schedules on nutrients uptake of sunflower
K Preethika Reddy, M Uma Devi, V Ramulu, M Madhavi
A field experiment was conducted at Water Technology Centre, College farm, Rajendranagar, Hyderabad during rabi 2017-18 with sunflower (var. DRSH-1). The experiment was conducted in a randomized block design with three replications in a sandy clay loam soil, alkaline in reaction, non saline, low in available nitrogen, medium in available phosphorus and potassium. The treatments were nine with combinations of N (75 kg ha-1) and K (30 kg ha-1) fertilizers applied by fertigation through ventury at different intervals viz., 3 days and 4 days. Drip irrigation was scheduled once in 2 days at 0.8 Epan. Fertigation was imposed at 16 DAS to 88 DAS and completed in 19 and 10 splits in 4 and 8 days interval respectively. The source of N and K fertilizers was urea and potassium sulphate respectively. At harvest, the total N content ranged from 0.59 to 0.89 % and 1.37 % to 1.84 % in sunflower stalk and shoots respectively. The total P content ranged from 0.12 to 0.21, 0.24 to 0.32% in sunflower stalk and shoots respectively. The total K content ranged from 0.91 to 1.46, 0.58 to 0.87% in sunflower stalk and shoots respectively. At harvest, the highest total uptake of N (281.6 kg N ha-1), P (55.5 kg P ha-1) and K (252.6 kg K ha-1) was noticed in T7 (75-30 kg N and K2O ha-1 at 4 days interval). Significant correlations were noticed between uptake of N, P and K with sunflower seed yield.