The effects of different burning intensities on soil properties during recovery stage of forests in subtropical China

Abstract

In order to explore the dynamics of soil properties and identify critical soil indicators that can explain most of the variation of soil properties due to prescribed burning at different intensity levels during the recovery stage of forests in subtropical China, an experiment was conducted in humid subtropical forests located in Hunan of China. In the experiment, no burning (control), and low, moderate, and high intensity fires were designed; soil samples under the burning intensities were collected; and soil properties including bulk density (BD), pH, soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), and soil water repellency (SWR) were measured. Moreover, Pearson correlation analyses among the soil properties and principal component analysis under the burning intensities were carried out, and statistically significant differences of the soil sample means were also tested at the significant level of 0.05. The results showed that the increase of the burning intensity led to significant increases of BD, pH, and SWR; significant decreases of SOM; and no changes of TN, TP, and TK. Most of the correlation coefficients did not differ significantly from zero under the control, and the correlations became stronger and significant as the burning intensity increased. Some of the correlations even changed the signs. As the burning intensity changed from the control, low, and moderate to high, the critical soil indicators shifted from SOM, TN, and TP to BD, pH, and SWR.