Critical saline concentration of soil and water for rice cultivation on a reclaimed saline soil

摘要

Reclaimed tidal areas for rice cultivation are irrigated with salt mixed water when there is severe drought. Therefore, we identified the critical concentration of saline water for rice growth on a reclaimed saline soil in Korea. The experiment wasconducted at the Kyehwado substation of the National Honam Agricultural Experiment Station (NHAES) during 2001-2002. Two experimental fields with 0.1-0.2 percent for low soil salinity and 0.3-0.4 percent for medium soil salinity levels were used. The experiment involved four levels of salt solution mixed with sea water (at 0.1, 0.3, 0.5, 0.7 percent) compared with a control using tap water in a split-plot design with three replicates. Saline solution was applied only two times at seedling stage (10 DATand 25 DAT) for 5 days. Gyehwabyeo and dongjinbyeo, japonica rice varieties, were used in this experiment. Plant height and number of tillers sharply decreased in the 0.5 percent saline water in low soil salinity level and 0.1 percent in medium soil salinity level. For yield components, panicle number per unit area and percentage of ripened grain dramatically decreased in the 0.5 percent saline water in low soil salinity and 0.1 percent in medium soil salinity level. But 1,000-grain weight of brown ricedecreased sharply in the 0.5 percent saline water in low soil salinity and 0.3 percent in medium soil salinity, indicating that this component was not much affected unlike other yield components. Milled rice yield decreased significantly with saline water level in both low and medium soil salinity. In the 0.7 percent low saline soil, the yield index was only 36 percent compared with the control. In medium soil salinity, even the control plot showed only 62 percent yield index compared with the controlin the low soil salinity treatment. Results indicated that the critical concentration of saline water for rice growth in terms of economical income of rice production was 0.5 percent in low soil salinity and tap water in medium soil salinity.