岷江上游23年生油松纯林下凋落物与土壤截留降水的效应

Interception Effect of Precipitation by Litter and Soil under 23-Year Artificial Pinus Tabulae formis Forest in Upper Reaches of Minjiang River

为了评价人工林下凋落物与土壤截留降水的能力,定位监测和分析了岷江上游23年生人工油松纯林下凋落物层和土壤层对65次降水事件的截留与分配过程。结果表明,65次林外降水总量为400.9 mm,其中208.726mm以穿透雨、33.388 mm以树干茎流进入林地,凋落物层、土壤层分别截留25.695,214.375 mm,截留率分别是6.41％,53.47％。但林外降水量<0.3 mm时,不产生林内降水,凋落物与土壤层不能截留降水。在0.3～10 mm降水范围内,土壤截留量随着降水增大呈增加趋势,而凋落物层截留率先增后减,但降水量>10 mm后,土壤截留率逐渐趋于稳定,呈较小波动(63.46％～73.58％),而凋落物截留率趋于稳定,并略有下降趋势;土壤截留量与林内外降水量、土壤截留量与茎流量均呈显著线性相关关系。综合分析表明,人工油松林凋落物层和土壤层对降水均有一定的拦蓄截留效应,其中:土壤层>凋落物层,土壤层的截留量达同期林外降水量的1/2以上。

The precipitation characteristic and interception effects of precipitation by the litter and soil layer in the 23-year artificial Pinus tabulaeformis forest were monitored and studied in the upper reaches of the Minjiang River. The results showed that the total input of rainfall to the forest ecosystem was 400. 9 mm by 65 sampled events, of which the input of through-fall and stem-flow were 208. 726 mm, 33. 388 mm. The litter and soil in- tercepted by 25. 695, 214. 375 mm respectively, occupying 6. 41 %, 53. 47% of the total input of rainfall. The in- terception function of the litter layer cannot behave before the through-fall began under rainfall more than 0. 3 mm. The interception was much large difference among every layer when the precipitation is 0～15 mm at a time, headed for a specific value when the precipitation is over 15 mm at a time. The linearly relationship among soil in- terception, stem-flow, rainfall inside and outside of stands were established. And the results also showed that the layer of litter and soil in artificia1 Pinus tabulaeformls forest played a significant role in storage and interception to precipitation, and they performed different functions in the ecosystem. The effect of interception in the soil layer was higher than that in the litter layer, soil interception accounted for half of rainfall on an average.