Effect of Gap Size on Seasonal Variation of Soil Chemical Properties in Subtropical Forest, Southern China

Abstract

Gap area has an effect on the soil chemical properties. To find out whatever the effect of gap area on the soil chemical properties, gap area was divided into small, medium, and large gap sizes and under the canopy as control.  To determine the soil chemical properties such as pH, organic matter   (OM) (g/kg), total nitrogen (TN) %, total carbon (TC) %, C/N ratio, total phosphorus (TP) (g/kg), total potassium (TK) (g/kg), available phosphorus (AP) (mg/kg), available potassium (AK) (mg/kg), and hydrolysable nitrogen (HN) (mg/kg), the grid system (3×3 m²) was applied for collecting the soil samples over the entire gap area at 20 cm depth. The results showed that most of the soil chemical properties varied significantly with respect to the gap sizes and the seasons. The summer season had greatly influenced all the chemical properties when compared with the winter season. However, the soil chemical properties exhibited irregular variation in different gap sizes. Moreover, a strong significant positive correlation among TN, TC, C/N, and OM was found. The highest soil OM in the large gap size indicated the high potential of nutrient supply for the plant growth. The results of this study provide useful information for the regeneration and conservation of C. kawakamii.