Evaluation of placement methods for urea supergranules in wetland rice (Oryza soil sativa) B.K. MISHRA, A.K. DAS, A.K. DASH, D. JENA , S.K. SWAIN^

Abstract

-- A field experiment was carried out in a lowland soil, having fine loamy mixed hyperthermic Epiaquept, during winter season of 1994-95 and 1995-96 to evaluate the method of urea supergranule (USG) placement in wetland rice (Oryza sativa L.). The experimental plan was randomized block design with 3 replications. The USG was applied @ 76 kg Nlha either as surface broadcast or as deep placement at soil depths of 2.5, 5 or 7.5 cm by manual or mechanical means along with prilled urea (PU) split. Placement of USG significantly increased both the grain and straw yields of rice in comparison to PU or USG broadcast. The response of rice to nitrogen was more under USG placement than split application of PU. Nitrogen-use efficiency of rice was increased from 18 -, kg grainlkg N applied as PU to as high as 26 kg grainlkg N applied as USG. Similarly, the relative efficiency of USG was increased by 40% over PU. The apparent recovery of N in rice was also increased from 21% in case of PU to 40% for USG.