RICE RATOONING - IRRI books - International Rice Research Institute

130 RICE RATOONINGvakiambiaty, hosy, vatomandry, gondra, tsipala, ririnina, and asarake in differentregions of Madagascar and generally different varieties and different lands are used.These local terms can be broadly translated as first, intermediate, and second-seasonrice crops; slash-and-burn type (tavy); and upland rainfed (tanety) rice crops.Madagascar has tremendous potential for increasing rice production andcould become a top exporter of rice in Africa in the future.PREVIOUS WORK ON RICE RATOONINGAlthough little work has been done on ratoon cropping in Madagascar, literature isavailable in report form from Lac Alaotra region (786 m), where testing for ratooncropping was carried out by Arraudeau and Dechanet (1) from 1960 to 1963. Theytested some varieties during a 3-yr period. No. 34 (Makalioka local selection) andChianung 8 were kept as control without ratooning and Taichung 150, Kameji,No. 1300, Shinei, Tomoe Masari, Toyokekari, and Shintsu were ratooned inreplicated trials. Ratoon crop yields ranged from 301 kg/ha for Toyokekari to 961kg/ha for Taichung 150. The main crop and ratoon crop yields of these varietiescould not surpass the yields of Chianung 8 (5.3 t/ha) and No. 34 (7.4 t/ha). Otherstudies showed that short-duration (122-146 d) Taiwanese and japonica varietiesproduced higher ratoon yields than long-duration checks Chianung 8 (153 d) andNo. 34 (176 d). The total yield ranged from 2.0 t/ha for Shintsu to 7.4 t/ha forNo. 34. Taichung 150 gave a total yield (main crop and ratoon crop) of 5.03 t/ha.Arraudeau and Dechanet concluded that the role of short-duration varieties isimportant because harvest is in March when rice is scarce and expensive ascompared with No. 34 which is harvested in April-May. These early varieties can beused for ratoon yield. However, the ratoon crop yields were not superior to those ofNo. 34 in quality and quantity, and bird damage was considerable.Dobos (3) also studied ratooning of rice at Lac Alaotra. He used 6 varieties, in5 replications, 2 cutting heights of main crop, and 100 kg N/ha for the main crop and40 kg N/ha for the ratoon crop.He concluded that 5 cm cutting height produced more homogeneous andsynchronous ratoons than 30 cm. Kaoshung 21 was best for fodder crop yield.Denton (2) mentioned that local variety Mampana is used for ratoon croppingin Marozafy village in Mananjary area in the southeast coast. The variety is seeded inNovember and December, transplanted in February, and harvested in April andMay.POSSIBLE AREASThere are several areas where ratoon cropping can be practiced in Madagascar(Fig. 1) but the following three areas could be more important in near future, withproper varietal selection.1. Marovoay region. Total rice area in this region is about 30,000 ha. Threetypes of rice culture are grown in the area.