RICE RATOONING - IRRI books - International Rice Research Institute

RICE RATOONING IN KERALA 229such injury. From this angle also, ratooning can be a useful alternative croppingsystem. Ratooning possibility in this situation is estimated at 1,000 ha.High-altitude areasLong duration of the first crop varieties due to cold weather makes irrigation waterscarce for a fresh crop over one-third of the hectarage at high altitudes. Ratooning isconsidered a possible way to bring an additional area of 8,000 ha in this region underrice with the limited water available.VARIETAL CHOICERatoon yields of some rice varieties were evaluated in three trials (Table 2, 3, 4). Theresults, although scanty, indicate that• for better ratoon yields, varieties of moderately long duration (140-160 d)are to be preferred.• the ratoon crop can be harvested in about 55-60 d after the main cropharvest, irrespective of the duration of the variety.• the grains from the ratoon crop are not as heavy and plump as those fromthe main crop.• per day productivity of the ratoon crop is comparable to, and even betterthan, that of the main crop.POTENTIALS AND PROBLEMSIn Kerala, where there has been a reduction of area under rice from 874,000 ha in1972-73 to 740,000 ha in 1982-83, bringing more new areas under rice is consideredvery difficult for socioeconomic reasons. The need is also to reduce cultivation costsby various technological adjustments. Ratooning, if well established with goodratooning varieties and appropriate ratoon management technologies, can be rightlyconsidered a new strategy with proportionately less pressure on its limited irrigationpotential.Table 2. Ratoon performance of seven short-duration rice varieties, Pattambi, India, 1981.Main crop aRatoon crop bVariety Duration Grain Per day Duration Grain Per day(d) yield yield (d) yield yield(t/ha) (g/m 2 ) (t/ha) (g/m 2 )Chianung Sen yu – 13IR9209-48-3-2lR9761-19-1IR13427-40-2-3-3lR13429-109-2-2-1IR13429-287-3Taichung Sen yu 285Mean1131041031131081131131103.64.94.94.64.64.83.64.43.24.74.74.14.34.23.24.151606151565151540.40.30.30.50.40.30.40.40.70.50.50.90.80.60.70.7a Fertilizer was applied to supply 40 kg N, 20 kg P, and 20 kg K/ha. b No fertilizer was applied.