The objective of this experiment is to study the effect of incorporated rice straw combined with chemical fertilizer (CF, basal with fertilizer 16-16-8, 40 kg/rai and top dressing with urea (46%N), 60 kg/rai) on rice yield, soil bulk density, pH and electrical conductivity. Six treatments with 4 replications in RCBD were laid out. Rice seeds cv. Phatumtani1 were sown. The results showed that plots with incorporated rice straw, 1-4 t/rai, gave rice yield ranged from 660 to 757 kg/rai, which higher than that of the control (283.55 kg/rai). Bulk density of the soil with combination of incorporated rice straw and CF were 1.27-1.17 g/cm, significantly different compared to the control, 1.45 g/cm. Rice straw at all rates with 1 Corresponding author: patsael@kku.ac.th * นกศกษา หลกสตรวทยาศาสตรมหาบณฑต สาขาวชาปฐพศาสตร คณะเกษตรศาสตร มหาวทยาลยขอนแกน ** อาจารย ภาควชาพชศาสตรและทรพยากรการเกษตร คณะเกษตรศาสตร มหาวทยาลยขอนแกน *** รองศาสตราจารย ภาควชาพชศาสตรและทรพยากรการเกษตร คณะเกษตรศาสตร มหาวทยาลยขอนแกน วารสารวจย มข. (บศ.) 13 (2) : เม.ย. ม.ย. 2556 2 chemical fertilizer did not affect soil pH during the growing season, but they increased the soil electrical conductivity (EC) with high significant differences through the growing season. Correlation coefficient (r) between rice straw rates and soil bulk density after growing season was negative significantly, while those between rice straw rates and electrical conductivity and rice yield were positive with very high significance. This experiment concluded that some physical and chemical properties of paddy soil as well as rice yield could be improved by rice straw incorporation. ค�าส�าคญ : ฟางขาว ผลผลตขาว คณสมบตของดน