Nitrogen and Potassium Based Fertigation Response on Plant Growth, Yield and Quality of Sweet Orange (Citrus sinensis Linn. Osbeck) cv. Sathgudi

Sweet orange ( Citrus sinensis Linn. Osbeck) is the major fruit crop in the state grown in nearly 2.5 lakh ha with a production of 3.25 lakh MT. Sweet orange respond very well to the application of nutrients either through soil or through fertigation. Though 70 % of area is under drip irrigation farmers are applying fertilizers through soil only. Hence the present study is taken up to find out the optimum doses of N & K that can be applied through fertigation which will increase the nutrient use efficiency and reduce the cost on labour . The treatments in the experiment included T 1 - 100% of the recommended dose Nitrogen and Potassium applied through fertigation system, T 2 - 75% of recommended dose N and K applied through fertigation system, T 3 - 50% of recommended dose N and K applied throu gh fertigation system and T 4 - recommended dose of N and K are applied directly to the soil. The recommended dose of nutrients were 1500g N, 350g P 2 O 5 & 400g K 2 O per plant per year applied to soil in two split doses during July and January months. Urea and Muriate of Potash were used as source of N and K in the fertigation treatments. Fertigation treatments were given at 15 days interval and fruit yield and quality were measured at harvest. Results have indicated that highest growth parameters i.e., plant height (3.09 m) canopy volume (20.9 m 3 ) were recorded when 50 % recommended dose of N &K were applied. However, the number of fruits per tree (345.69) and fruit yield (61.69 kg/tree ) were found significantly highest in plants supplied with N &K at 75% recommended dose through fertigation. The same treatment has also given the highest C: B ratio of 1:2.29.