RICE RATOONING - IRRI books - International Rice Research Institute

ALTERNATIVE TO DOUBLE CROPPING IN TROPICAL ASIA 13Table 8. Costs of rice ratooning – an estimate for lntan rice grown in Coorg Districtof Karnataka, India, in 1986.Expenditure/hacostRs US $Nitrogen fertilizer (75 kg N/ha)Irrigation (at 4 irrigation/mo)10 mo 5 laborers aWeeding twice at 15 laborers/ha30 laborersPlant protection chemicalsHarvesting charges - 25 laborersThreshing, winnowing, and other postharvest chargesTotal cost of cultivation/ha375.0052.50315.00250.00262.50250.001505.0025.903.6021.7017.2018.1017.30103.80a Labor charges/day for 8 h work is Rs. 10-50 or US$0.72/individual.CONCLUSIONThe available literature on ratoon rice to date is only suggestive rather thandefinitive. Systematic research on ratoon cropping, its adoption, and economics isneeded to make this unique cropping system a practical and paying enterprise.There is significant scope to adopt this technology, particularly in the tropicalmonsoon areas where rice is the principal crop. Where rice is cultivated mostly as amonocrop, resources go to waste during the off-season. The area that could be putunder a ratoon system could be roughly estimated as 30% of the rice area in tropicalAsia, or about 26.63 million hectares (as of 1978). The average yield of rice in tropicalAsia is 2.7 t/ha. The data available on ratoon rice indicate that yields up to 50% ofthe main crop are possible.Assuming that the entire lowland rice area can be put under ratooning, thetotal production from ratoon cropping could be as high as 35.95 million tonsannually.FUTURE DIRECTIONS1. Most of the work on ratooning so far has dealt with irrigated rice. Research onratooning under residual moisture (rainfed), which is much more important, isscanty. There is need to know the prospects of ratooning in rainfed conditions totide over moisture stress during later growing phases of the crop.2. The genetics of inheritance of ratooning has not been properly understood. Thisshould be given major emphasis, and systematic breeding efforts should beundertaken to synthesize cultivars specially for ratooning.3. Cultivars suitable for different climates, altitude, and purposes should beidentified to optimize ratoon rice yields.4. Studies on control of tillering and growth analysis should be initiated todetermine the physiological phenomenon involved in tiller regulation and cropgrowth.