Response of transplanted rice to levels, splits and timing of NPK application
2009
Masthanareddy, B.G. | Hebbara, M. | Patil, V.C. | Patil, S.G.
The effect of two levels (150:33:62 and 250:55: 104 kg N, P and K ha-I), two types of splits (N splits and NPK splits) and four timings and proportion of NPK application: 50% at transplanting (TR), 25% each at active tillering (AT) and panicle initiation(PI) (Ti), 33% each at TR, AT and PI (Tz), 25% each at TR, AT, PI and panicle emergence (PE) (T3) and 25% each at TR, AT, PI and 12.5% each at PE and beginning of grain filling stage (BGF) (T 4) on losses, uptake and use efficiency of N in transplanted rice (Oryza sativa L) was studied at Agricultural Research Station, Gangavathi, Kamataka, during kharif 2000 and summer 2001. Ammonia volatilization losses accounted for less than 7% of the applied N. Application of 250:55:104 kg N, P and K ha-1 recorded higher ammonia loss (9.71 and 9.19 kg N ha-I, during kharifand summer, respectively) than recommended level of 150:33:62 kg N, P and K ha-I (7.69 and 7.45 kg N ha-I, respectively).l:Iowever, split and timing of NPK application had no significant effect on total ammonia losses. The leaching losses of N ranged from 3.6 to 7.0% of applied N. The losses were significantly higher at 250:55:104 kg N, P and K ha-I (12.92 and 10.83 kg N ha-I during kharif and summer, respectively) than the recommended dose. Leaching losses were more under NPK splits than N splits. Split application of NPK upto beginning of grain filling stage for long duration rice cultivars in kharif and upto panicle emergence stage for medium duration rice cultivars in summer improved the recovery efficiency of N and resulted in higher N uptake and grain yield.
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