RICE RATOONING - IRRI books - International Rice Research Institute

N FERTILIZER MANAGEMENT FOR MAXIMUM RATOON YIELDS 193Table 5. Lemont ratoon crop yield as influenced by N applied immediately aftermain crop harvest at Beaumont, Texas.Main cropN appliedAverage ratoon crop yield (t/ha),postflood after main crop1984 and 1985N timing a harvest (kg/ha) Low main crop N High main crop NNo applicationPDPD and HdHdHd20561120561120561120561120561121.92.62.81.72.52.72.02.53.12.22.93.52.42.93.31.72.32.91.82.22.62.22.53.22.12.82.92.22.73.1LSD (.05) = 0.25a PD = panicle differentiation. Hd = heading, Hd2 = 2 wk after initial heading.rice yields. Data suggest that N application at main crop PD followed by Napplications near main crop heading would increase total yields of certain varieties.However, additional experiments will be required to verify this.Applying one-half or all of the postflood N at heading or 2 wk after headingrather than at PD provided earlier ratoon crop tillering and 7-10 d earlier ratooncrop maturity.Nitrogen fertilizer applied immediately after main crop harvest has a moreevident and positive influence on ratoon crop yields than N applied before main cropharvest.REFERENCES CITED1. Bahar, F. A., and S. K. De Datta. 1977. Prospects of increasing tropical rice production throughratooning. Agron. J. 69:536-540.2. Chauhan, J. S., B. S. Vergara, and F. S. S. Lopez. 1985. Rice ratooning. IRRl Res. Pap. Ser. 102.19 p.3. Dat, T. V., and M. L. Peterson. 1983. Performance of near-isogenic genotypes of rice differing ingrowth duration. II. Carbohydrate partitioning during grain filling. Crop Sci. 23:243-246.4. Evatt, N. S. 1958. Stubble rice production tests 1956-57. Prog. Rep. 2018, Texas Agric. Exp. Stn.,Texas A&M Univ., College Station, Texas.5. Hsieh, C. F., C. Y. Lin, and T. S. Lai. 1983. Effects of nitrogen fertilizer and delaying harvest on therecovery rate of ratoon rice. Bull. Taichung Dist. Agric. Imp. Stn. 7:38-44.6. Ichii, M. 1984. Studies on the utility of ratoon traits of rice as the indicator of agronomic characters inbreeding. Mem. Fac. Agric., Kagawa Univ., No. 44. 49 p.7. Mengel, D. B., and F. E. Wilson. 1981. Water management and nitrogen fertilization of ratoon croprice. Agron. J. 73:1008-1010.8. Murata, Y., and S. Matsushima. 1975. Rice. Pages 73-99 in Crop physiology. L. T. Evans, ed.Cambridge Univ. Press, United Kingdom.