Effects of Canopy Gaps on the Physical and Chemical Properties of Rhizosphere and Bulk Soil with Seasonal Changes

In order to understand canopy gap disturbance effects on soil nutrient dynamics in Platycladus orientalis plantations, soil physicochemical properties of pH, carbon and nitrogen in rhizosphere and non rhizosphere soil under 27 different scales of canopy gaps including small, medium and large were studied in southeastern slope of Jiuli Mountain in Xuzhou. The results showed that the water content of the rhizosphere and bulk soil was decreased by canopy gaps. The pH of rhizosphere and bulk soil under different scale canopy gaps was neutral and alkaline. The total content of carbon and nitrogen in rhizosphere and bulk soil decreased after forest canopy gaps formation. Canopy gaps reduced C/N in bulk soil. C/N ratio in rhizosphere soil under small scale canopy gaps was significantly higher than that in control group. This indicates that the effect of canopy gaps on the rhizosphere effect of soil C/N has a double feedback effect with the season. A canopy gap with a radius of 4 m is most favorable for forest development and nutrient cycling. The results can provide a scientific basis for the further understanding of the effect of canopy gaps on soil nutrient dynamics and the ability of forest disturbance to respond to stability mechanism of forest ecosystem.