Abstract: The study on the soil water content, temperature, bulk density, hardness, and mechanical components under 7 artificialEucalyptus forests and 1 Acacia forest in Dongcheng Town of Danzhou City showed that soil water content in the Eucalyptus forest with 50% coverage of understory vegetation was 11.2～62.9 g·kg^-3higher than that without understory vegetation, and 27.6～38.2 g·kg^-3 higher in the forest with litter coverage than without it. Soil temperature under the Acacia forest with understory vegetation was higher than that with no understory vegetation or with high coverage of forest canopy, but lower than that in open area. Soil hardness under the Eucalyptus and Acacia forests with understory vegetation was 5.49～18.76 kg·cm^-3 lower than that without understory vegetation, and soil bulk density under the Eucalyptus forests with high coverage of understory vegetation was 0.33～0.48 g·cm^-3 lower than that with low coverage of understory vegetation or without it, under Acacia forest, and at the plot with 30% of herbage coverage. The results indicated that understory vegetation, litter, and forest canopy were the important factors affecting the soil physical properties under Eucalyptus and Acacia forests, and thus, it was very important to remain some understory vegetations and litters of these forests for improving soil physical characteristics and developingEucalyptus and Acacia forests.

Key words: Chemical regulation agent, Rice, Insufficient illumination, Heading-filling, Comprehensive evaluation