RICE RATOONING - IRRI books - International Rice Research Institute

90 RICE RATOONINGTable 4. Yield of main and ratoon crops of rice at Karemane village, Karnataka,India, 1977-78.Main cropTreatment a Grain yield N applied(t/ha)(kg/ha)Ratoon crop(t/ha)Grain yield% ofmain cropF 0 N 0F 0 N 0F 0 N 120F 0 N 120 P 26F 0 120 P 26 K 50F + N 0F + N 0F + N 0F + N 60F + N 90Mean2.12.03.04.65.53.13.33.33.34.23.405025250500.512.512.512.5–2.37.06.56.34.27.76.14.25.24.65.411035021713776248185127158110159a F 0 = no farmyard manure (FYM), F = 12 t FYM/ha.Fertilizer and grain yieldAnother study of rice ratoon cropping patterns with Intan was conducted on aprivate farm in Chikkamagalur District in the 1977-78 wet season. The experimentwas seeded in June 1977, transplanted on 16 Jul, and harvested on 12 Dec. Theratoon crop was ready for harvest on 24 Apr 1978, but was harvested on 2 Maybecause it was maintained as a demonstration crop for visitors. Main and ratooncrop yields obtained in the experiment at Karemane village, Karnataka (1977-78),are given in Table 4.The ratoon crop, which matured in 133 d, generally yielded more than themain crop (Table 4). Ratoon crop yields ranged from 76 to 350% of the main cropyields. As with N applied 30 d after cutting main crop, at 0 kg N/ha yields averaged93% of main crop yield; at 12.5 kg N/ha, 132%; at 25 kg N/ha, 180%; and at 50 kgN/ha, 300%. The ratoon crop had 24% shorter growth duration and 59% highermean yield than the main crop. This good yield does not represent an average farmsituation and needs clarification.Because the main crop treatments were not originally planned for a ratooncrop study, lack of replications limits the data’s value. But the treatment thatreceived the recommended dose of N-P-K in the wet season and N in the ratoon cropmay be close to an average farm situation. Interestingly, ratoon yields were high evenin plots where the main crop yields were low.PERFORMANCE IN FARMERS’ FIELDSData on main and ratoon crop yields and on crop duration were collected from 14randomly selected private farms (Table 5). The ratoon crops showed a wider rangeof yields than did the main crops. Yields ranged from 0.68 t/ha to more than 4 t/ha.However, mean yields are encouraging and suggest that the system has highpotential. But more research is needed to stabilize yields by developing varietiessuitable for ratoon cropping and optimum management practices.