Soil Improvement (Nampong series) by Ruzi and Verano with Chemical Fertilizer   Seri Chaturangkakul Somnuk Sritongchim Yuwadee Buttrama and Arthit Sukhasem   ABSTRACT         The study on Soil improvement (Nampong series) by Ruzi and Verano with chemical fertilizer was conducted in Boarabu district Mahasakam province during 1992 - 1994. The experiment design was RCB with 3 replications while treatments used in this study were ;- the ratio of planting seed between Verano and Ruzi by weight (1 : 1, 1 : 2, and 2 : 1) also chemical fertilizers (15-15-15) were applied at the rates of 0 , 10, 20, 30, and 40 kg/rai accordingly. The objectives of this study were to find out suitable rates of chemical fertilizer applied, the best planting seed ratio between Verano and Ruzi and also soil chemical changed. The result of this study showed that yield of Verano and Ruzi fresh weight were statistically different as effected by chemical fertilizer in all rates (4,913 6,871 6,026 7,435 and 7,716 kg/rai) The ratio of planting seed found that the best ratio between Verano and Ruzi was 2 : 1 gave the yield was 6,950 kg/rai . Using vary rate of seeds was not make soil fertility diferrent.         Keyword : Ruzi, Verano, Chemical Fertilizer