炼山对杉木人工林生态系统的影响 Ⅰ炼山初期林地水土流失的初步研究

Effect of Control Burning on the Ecological System of Chinese fir Plantation

本文采用径流小区定位观测法分析研究炼山与不炼山的水土流失差异。通过一年的研究结果表明:炼山后第一年水、土、肥流失十分严重,炼山的年径流量为2743.49m^3/ha,年土壤流失量为24.811T/ha,分别是不炼山的11倍和88倍。大量水土流失伴随着养分流失。有机质、速效氮、磷和钾的流失量分别为不炼山的15倍、24倍、16倍和5倍。经回归分析、炼山因素在影响本区水土流失诸因子中占主导地位。在本试验条件下24°—32°可能是水流面蚀强度的临界坡度。

The method of the fixed position observation of the runoff plot was used in thsi paper to study difference of soil and water loss between the control burning and not burned. The results obtained from this study showed that the soil erosion, water and fertilty loss were very serious in the first year after control burning, theannual runoff amount of the control burning was 2743.49m3/ha; the loss of soil was 24.811T/haperyear, 11 times and 88 times that of the not burned, respectively. Soil erosion and water loss would be compared with nutrients. The losses of the organic matter, the availabilility of N, P, and K were 15 times, 24 times, 16 times and 5 times as large as that of the not burnt, respectively. Through the regression analysis, the results showed the control burning was the main factor affecting the soii erosion and water loss in the studied area. The slope of 24-32 was probably 1he critical slope of rainfall surface erosion intensity under this experimental condition.