RICE RATOONING - IRRI books - International Rice Research Institute

12 RICE RATOONINGrelating to seed viability are available, but cooking quality and nutritive value of seedof ratoon rice are yet to be studied.RATOONING IN RICE-BASED CROPPING SYSTEMIn an analysis of double-cropping yield potential of three cropping sequences, Baharand De Datta (2) observed the following yields: 1) 11.7 t/ ha for transplanted -transplanted rice cropping sequence; 2) 11.4 t/ha for transplanted - direct seeded;and 3) 7.6 t/ ha for transplanted - ratooned. Although the ratoon crop gave a loweryield, it matured earlier (Table 7) and required less water, input, and labor cost. Thesystem appeared useful for increasing production with limited resources.It is also essential to work out yield performance under a system of directseededrice followed by transplanted rice. It is expected that the system will givehigher yields by reducing missing hills per unit area and produce maximum numberof tillers.In studies on nitrogen fixation by blue-green algae (BGA), Watanabe et al (26)noted that BGA could fix nitrogen more efficiently in ratoon rice than in the maincrop. There is need for intensive research on BGA and other biofertilizers to reducedependency on nitrogen, an expensive chemical input.ECONOMICS OF RICE RATOONINGThe average yield of lntan in the blast-free areas in the Coorg District (Karnataka) isestimated at 3.5 t/ha. The levy rate of rice in 1986 was Rs.1650/t (US$114/t). Ifratoon cropping is to be economical, it should yield at least 50% of the main crop.Total returns per ratoon crop would then be Rs.2887.50/ha (about US$199/ha).The farmer will realize a net profit of Rs. 1382.50, or US$95.70, which is significant(Table 8).More detailed studies on the economics of rice ratooning as a whole areneeded to determine whether ratooning will be a profitable enterprise in rice-basedcropping system areas.Table 7. Double-cropping grain yield performance of six semidwarf rice varietiesin three cropping systems. aCultivarProductionGrain yield (t/ha) Field duration (d) (kg/ha per d)T-T T-DS T-R T-T T-OS T-R T-T T-OS T-RIR206l-464-2lR1561-228-3IR74782-6IR28lR2061-465-1lR2061-632-3-110.211.78.711.89.19.49.310.47.69.68.98.76.47.65.18.76.47.31831771651831771801971971741971971971631531351671721425666536251524753444946443950385237-a T = transplanted, DS = direct-seeded, R = ratooned. Source: Bahar and De Datta(2).