RICE RATOONING - IRRI books - International Rice Research Institute

RATOONING IN CHINA 83Table 2. Rice variety 40-1 ratoon yield performance (1).Year Location Area (ha)Yield (t/ha)Main crop Ratoon crop Total19841985FCRI aHuang Gong County0.076 7.8113.37.204.674.1612.4811.36a Food Crop Research Institute, Hubei Academy of Agricultural Sciences,Wuchang County.1,000-grain weight = 25.4 g). High grain yields are obtained in both main and ratooncrops (Table 2).The total grain yield of main and ratoon crops of the variety 40-1 equaled thatof double-cropped rice. In addition, the labor force required is substantially reducedand the seedbed from which a certain amount of grain can be obtained is saved, for atotal saving of 0.6 t grain/ha (1).Plant heights of main and ratoon crops of the variety 40-1 were 94 cm and64 cm, respectively; the variety also had high tillering, large culms, and a strong rootsystem. The panicles of the main crop were large (106 filled grains/panicle). Theuppermost bud of the stubble was 24 cm above ground level, cutting height wasabout 30 cm. Each of the buds above and at ground level might regrow. The 40-1ratoon crop produced 465 panicles/m 2 and 46 filled spikelets (89%) per panicle andgrain quality was good, surpassing that of the main crop.A plan for ratoon cultivation of some 5,333 ha may be carried out to confirmthe performance of the varieties and cultural techniques in Hubei Province in 1986.Medium-duration hybrid rice. Cooperative experiments on growing mediumdurationhybrid ratoon rice were conducted in southeast Sichuan Province by 12institutes and colleges from 1983 to 1985. Demonstration fields of 1,346 ha showedthat, on an average, the main crop yielded 7.9 t/ha and the ratoon crop 1.8 t/ha.Grain yield was 25.9% higher than that of the local medium-duration hybrid rice(17). This hybrid ratoon rice may be planted on 10,000 ha in southeast SichuanProvince in 1986. It is reported that Jiangjin county has 53,000 ha of mediumdurationrice, of which 6,666 ha will be used for a ratoon crop. To carry out thisproject, a videotape recording made of the ratoon demonstration field in 1985 wasbroadcast repeatedly over a countywide television network to acquaint farmers withratoon crop cultural techniques. Cultural practices recommended for mediumdurationrice ratooning in southeast Sichuan Province are1. Use Zai Sheng You, Ai You 1, Shan You 63, for hybrid ratoon rice (Table3). The hybrid Zai Sheng You (Choayang 1A/Taiguodao Xuan) wasdeveloped by Sichuan Agricultural University. Its growth duration is 155 dfor the main crop and 55-60 d for the ratoon crop.2. Fertilize for ratoon tiller sprouting. Apply 35-70 kg N/ ha to the main crop14 d before harvest to increase sprouting rate and promote early andvigorous ratoon crop growth.3. Use a main crop cutting height of 30 cm. The buds at the second, third, andfourth nodes will regrow. For such a high-cut ratoon crop, weeding is notnecessary.