摘要：The reclaimed lowlands of Indonesia with the respective of 256 hectares of secondary block consisting of 16 hectares of tertiary blocks,were used for rice plant production. Paddy was planted during the rainy season of November to February. Then follow with water melon in March to May and during dry season from June to September corn is cultivated. One of the main factor on determining the cropping time is the fluctuations of water table in lowland area. Water retention (controlled drainage) mode was applied by the farmers especially during the rice growing period. The release of water in the canal to a depth of -50 cm below the canal bank had lowered the water table level to -20 cm. Therefore study aimed is to investigate the ralation of ammonium and nitrate soil with water table dynamics. The study wasto conducted within two growing season (wet and dry season). Soil sample were taken after nitrogen fertilizer appplication for analyzing soil ammonium and nitrate. The result showed tha groundwater level did not show the effect on nitrate release on the urea application stocked. However,on the high ground water level it appears to be more in control of ammonium release compared to the ground water level of -20 cm..
