RICE RATOONING - IRRI books - International Rice Research Institute

RICE RATOONING IN THE DOMINICAN REPUBLIC 632. The spring crop and the ratoon of rice in the Dominican Republic (7).The ratoon crop in the Dominican Republic is managed as a specific crop,with the objective of increasing its productivity. It is not simply left in the field forwhatever rice it yields. In fact, when the main crop stubble is left in the field withoutapplying additional inputs, farmers call the crop riso to distinguish it from the retoño(ratoon) that requires a second cutting after main harvest (5).The riso system is usually practiced by farmers who grow a photoperiodsensitivecultivar which they do not believe would yield a second crop if the stubble isrecut lower after main crop harvest. They seem to be aware that lower buds have notbeen affected by photoperiodic cycles with the same intensity as the higher buds.These farmers are happy with whatever riso crop they harvest, usually in about 60 d.The first activity in ratooning is to recut the stubble as soon as possible afterharvest. Cutting heights vary within and among locations. During the second half of1985, 14 of 16 farmers in Jicomé cut the stubble at 10 cm or lower. In Castañuelas,farmers recut as high as 17.5 cm. In general, more than half of the farmers recutstubble at heights of 10 cm or less.After cutting, the stubble is allowed to regrow for 2 wk, after which it is firstirrigated and fertilized (Fig, 3,4). The stubble is flushed with water until the regrowthcan withstand continuous flooding. The first fertilizer application is usually acomplete formulation, but sometimes K is not used. After 1 mo, the field is handweeded and additional fertilizer is applied. Most farmers use only N, as urea orammonium sulfate, for the second application.Just before flowering (about 65 d after cutting), a second hand weeding isusually done followed by pesticide application — mainly insecticides against stink