Effect of Nitrogen and Potassium Fertigation Schedules on Plant Growth Parameters and Fertilizer Use Efficiency of Sunflower

A field experiment was conducted at Water Technology Centre, College farm, Rajendranagar, Hyderabad with sunflower (variety DRSH-1) during rabi 2017-18 in a randomized block design with three replications and 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 E pan. 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. The soil was sandy clay loam in texture, alkaline in reaction, non saline, low in available nitrogen, medium in available phosphorus and potassium. The amount of total irrigation water applied was 3188 m3 and 4666 m3 in drip irrigation and furrow irrigation treatments, respectively. The N and K fertigation (75-30 kg N-K2O ha-1) at 4 days interval has recorded relatively higher plant growth parameters like number of leaves plant-1 (25.5), plant height (208 cm), SPAD Chlorophyll Meter Reading (55.7), leaf area index (3.5) and dry matter (158.1 g m-2) which were on par with N and K at 8 days interval. Higher N-FUE (12.8 kg seed yield / nutrient applied) and K-FUE (25.6 kg seed yield / kg nutrient applied) was recorded in application of N+K at 4 days interval.