摘要
以三峡库区柏木林为对象,定量研究了雨季(7月)林分中降雨的再分配及N、P两种养分元素的循环过程。研究结果表明:1)穿透雨量占总降雨量的79.70%,树干茎流占总降雨量的1.17%,树冠截留量占总降雨量的19.13%,地表径流系数平均为198%;2)由于淋溶作用,实际进入林地的穿透雨和树干茎流中总N和总P的含量均升高了较大的幅度。降雨时总N和总P含量的相对平衡值分别为0461 mg/L和0.075 mg/L,淋溶系数为1.86和2.94,迁移系数为0.57和0.29;3)柏木林生态系统中,N的总贮量为36. 00 x103kg/hm2,P的总贮量为2.512 X 103kg/hm2,其绝大部分(N为 99. 5%, P为 98. 8%)贮藏在土壤库中; 4)在有燃料输出的情况下,系统中的 N和 P循环效率分别为0.43和0.41。燃料的输出导致系统N和P循环效率降低,土壤中养分减少,从而导致系统养分的缺乏,生产力下降。
Based on the artificial Cupressus funebris forest in the Three-gorge region, a quantitative study on the redistribution of rainfall and nutrient cycling in rain season (July) were conducted. The through fall, the stemflow and the canopy interception accounted for 79. 70%, 1. 17 %, and 19. 13 % in the total precipitation, respectively. The average coefficient of the surface run - off was 1. 98 %. Because of the eluviation, the actual contents of total N and total P carried into the forestland by the throughfall and the stemflow had a great increase. In the rain process, the relative equilibrium levels of total N and total P were 0. 461 mg/L and 0. 075 mg/L, respectively, with leaching coefficients being at 1. 86 and 2. 94, respectively, and migration coefficients 0. 57 and 0. 29, respectively. In the Cupressus funebris forest ecosystem, the storage of N was 36. 00 X 103 kg/hm2 and P 2. 512 x 103 kg/hm2, with most of them stored in the soil. Under the condition of fuel output from the ecosystem, the cycling rate of N was 0. 43 and P 0. 41. The cycling rates of N and P decreased and the nutrient in the soil reduced as a result of fuel output. Consequently, the lackage of nutrients in the ecosystem was resulted and the lower productivity was therefore expected.
出处
《长江流域资源与环境》
CAS
CSSCI
CSCD
2000年第4期451-457,共7页
Resources and Environment in the Yangtze Basin
基金
国家自然科学基金重大项目!(39899370)
国家"九五"科技攻关资助项目!(96-920-04-12)
关键词
柏木林
降雨
养分循环
再分配
三峡库区
Cupressus funebris forest
rainfall
nutrient cycling
redistribution