Effect of azolla and inorganic N combined.
1987
Chandrasekharan V. | Thangamuthu G.S. | Balasubramanyan P.
The effect of azolla and inorganic N on growth and yield of lowland rice variety Co 43 were studied during 1983-84 wet and dry seasons. Soil was clay loam, with 261 kg available N/ha, 15.9 kg P/ha, 460.7 kg K/ha, and pH 7.9. The design was a randomized block with four replications. Seedlings were transplanted at 30 d at 20- x 10-cm spacing. Prilled urea (PU) or urea supergranules (USG) alone or in combination with azolla at 75:25 were compared. N rate was 100 kg/ha for all the treatments except control. PU was split-applied: 50% basal, 25% at tillering, and 25% at panicle initiation stages; USG was applied all basal, point placed, one week after transplanting. Super phosphate at 22 kg P/ha and muriate of potash at 42 kg/ha were basally applied. Azolla was incorporated one week before transplanting. USG at 100 kg N/ha or azolla at 25 kg N/ha with USG at 75 kg N/ha were equal in increasing dry matter production, number of panicles, grain numbers and grain and straw yields in both seasons.
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