Effect of cassava starch waste and potassium on Khao Dowk Mali 105 rice

Abstract

The experiment was conducted to investigate the effect of cassava starch waste (CSW) and potassium (K) on Jasmine rice CV. Khao Dawk Mali 105 (KDML 105) rice grown in Korat soil series was conducted in a farmer field in Ubon Ratchathani province. Experimental design was arranged in Factorial in RCBD. The first factor comprised the application of CSW at rates of 0, 0.5 and 1 t/rai. The second factor consisted of K fertilization at rates of 0, 0.25, 0.5, 0.75, 1 and 1.25 of the recommended rate basing on soil analytical data, which was 2.4 kg/rai of K₂O. Result showed that CSW applied as soil amendment reduced soil acidity, increased organic matter and available K, especially when applied at the rate of 1 t/rai and, as a consequence, significantly resulted in the rice having plant height, number of panicle per hill and straw weight all greater than that of the control but unclear in the case of rice grain weight. The soil fertilized with K at the highest rate of 3.0 K₂O/rai gave the greatest rice grain and straw weight (349 and 307 kg/rai, respectively), however; the differences were not clear when compared to other treatment using lower rates, but the amounts were significantly higher than those obtained from the control (278 and 209 kg/rai, respectively. The addition of K promoted better nutritional quality of KDML 105 rice grain, especially when applied solely at the rate of 2.4 kg K₂O/rai, and together with CSW at the rate of 1 t/rai that significantly stimulated the highest iron concentration in rice grain of 13.1 mg/kg. Potassium had no impact on K uptake in plant tissues while the highest K uptake in rice straw was found in soil amended with CSW at the rate of 1 t/rai. Rice grain yield had a liner correlation with K concentration in grain (r=0.51**) more significantly than the other plant nutrients.