Effects of Potassium Fertilizer on Grain Qualities of Khaw Dauk Mali-105 Rice

Abstract

Eight pot and field experiments were conducted to examine the effects of K fertilizer on grain qualities of Khaw Dauk Mali-105 aromatic rice. The qualities of cooked rice were evaluated by sensory methods. The results led to the following conclusions and recommendations. 1) The aroma and glassiness of cooked milled rice were relates to paddy yields, shoot dry matter (DM) and rates of K fertilizer but not to percent K in paddy and in shoot. 2) The softness of cooked rice was related to percent K in paddy and in shoot but not to paddy yields, Shoot DM and rates of K fertilizer. 3) The whiteness was related to paddy yields, shoot DM and rates of K fertilizer and percent K in shoot but not to percent K in paddy. 4) The stickiness was not related to paddy yields, shoot DM, rates of K fertilizer, percent K in paddy and percent K in shoot. 5) The strongest aroma was obtained from K fertilizer at the rate that was so much higher than the rate that produced maximum paddy yield that the paddy yield was reduced to 82% of the maximum. 6) The softest cooked rice was obtained when percent K in paddy and in shoot were 0.23 and 1.18 respectively, which was obtained from the K fertilizer rate that began to produce maximum paddy yield. 7) The whitest appearance was obtained in the rice with K fertilizer at the rate was so much higher than the rate that began to produce maximum paddy yield that the paddy yield was reduced to 98% of the maximum or that gave 1.98% K in the shoot. 8) The glassiest cooked rice was obtained with K fertilizer at the rate that was no much higher than the rate that produced maximum paddy yield that paddy yield was reduced to 55% of the maximum. 9) To produce high yield with high qualities, K fertilizer should be applied at the rate that begins to produce maximum paddy yield. 10) Rice grown on soils with K higher than the level that begins to produce maximum paddy yield would produce grains with stronger aroma, more whiteness and better glassiness but lower softness than that grown on soils with K at the level that begins to produce maximum paddy yield.