RICE RATOONING - IRRI books - International Rice Research Institute

122 RICE RATOONINGEXPERIMENTS ON RATOON CROPPINGIn areas where the ahu-sali sequence is maintained, the sali crop yield is very low,rarely exceeding 2 t/ha.But our studies (3) revealed that the most promising ratoon variety, C-3810, aderivative of Manila × IR22, produced a yield of 4 t/ha for the main crop and 2 t/hafor the ratoon crop in 179 d. Further studies the following year confirmed thestability of the ratoon yield for this variety.Thus, ratooning the ahu crop would be more profitable, giving higher totalyields of main plus ratoon crop, than late-planting a sali crop. Moreover, ratoonyields would be obtained at little added labor cost.On the other hand, early harvest of the ratoon crop would allow for timelyplanting of dry-season crops like wheat, rapeseed, and legumes in the same field.Such a three-crop sequence might be difficult with a sali main crop of rice in thesequence.Studies on cutting heights for ratoon cropping showed that ratoon yieldsremained about the same for cutting heights from 15 to 45 cm; below 15 cm, ratoonyields declined drastically.CONCLUSIONOn the whole, there appears to be distinct scope for rice ratoon cropping in thenortheastern region. However, we need to• survey the areas where ratoon cropping can be fitted profitably into thecropping sequence of the region;• identify suitable high-ratooning varieties for different types of land,emphasizing conversion of single-cropped ahu rice to double-croppedareas; and• evolve location-specific agronomic measures for stabilizing ratoon yields ata high level.REFERENCES CITED1. Anonymous. 1982. Basic statistics of North Eastern region. North Eastern Council. p. 34.2. Chauhan, J.S., B.S. Vergara, and F.S.S. Lopez. 1985. Rice ratooning. IRRl Res. Pap. Ser. 102. 19 p.3. Das, G.R., and T. Ahmed. 1982. The performance of semidwarf varieties as ratoon crop after summerharvest. Oryza 19(3/4):159-161.