Effect of timing and graded levels of nitrogen and potassium in SRI cultivation

A field experiment was carried out at Annamalai University Experimental farm, Annamalai nagar, during Kuruvai and Navarai in the year 2008-09. To study the timing and graded levels of nitrogen and potassium in rice crop under SRI (System of rice intensification) cultivation. The experiment was laid out on deep clay soil by adopting randomized block design with factorial technique (FRBD). The results of field experiment revealed that the maximum growth and yield attributes were recorded in the treatment which received P2O5 as fully basal dose and nitrogen as three split doses viz., 50% basal and 25% each at tillering and panicle initiation stages. Potassium was applied as 33.3% K2O each at 15, 30 and 45 DAT. This treatment significantly recorded higher grain yield of 6278.7 kg ha-1 in field experiment – I and 6577.9 kg ha-1 in field experiment – II; and the straw yield of 7010.3 and 7309.7 kg ha-1 in field experiment I and II respectively. The shoot and grain uptake of nutrients (N, P and K) were high during 15, 30 and 45 DAT and at harvest which received 33.3 % K2O each at 15, 30 and 45 DAT