杉木人工林水土流失及养分损耗研究
A Study on Soil Erosion and Nutrient Loss in Chinese Fir Plantation
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摘要: 1984~1996年在江西分宜县中国林科院亚热带林业实验中心的3个林场,分别对杉木人工林幼龄林、中龄林及近熟林进行了8组水土保持及养分循环方面多点的试验观测,对杉木人工林水土流失及养分损耗作了研究。结果表明,杉木人工林水土流失以幼林阶段为最大,其次中龄林阶段,最小是近熟林阶段。幼龄林地表迳流量为546.0m3·hm-2,土壤侵蚀总量为1005.0kg·hm-2,土壤侵蚀量尤为明显;中龄林地表迳流量为506.98m3·hm-2,土壤侵蚀总量为180.7kg·hm-2;而近熟林地表迳流量为477.25m3·hm-2,土壤侵蚀量可略而不计。幼龄林流失有机质50.049kg·hm-2,养分为31.508kg·hm-2;中龄林流失有机质为6.080kg·hm-2,养分流失量为2.096kg·hm-2,而近熟林养分流失量为10.784kg·hm-2,无有机质流失。幼龄林阶段土壤侵蚀量以造林当年为最大,以后逐年减少,第4年及以后随着林分郁闭度加大,流失量很少,而地表迳流量与林龄关系不密切。在板页岩发育的土壤条件下,土壤有较强的抗蚀能力,在杉木人工林经营的25a中,水土流失不严重,养分损耗很少。总的迳流量为1530.23m3·hm-2,侵蚀量为1185.7kg·hm-2,流失有机质为56.28kg·hm-2,流失养分44.383kg·hm-2,其中以流失钾肥为最多。因此在杉木人工林经营中,仅就地表迳流及侵蚀量而论,在板页岩发育的土壤上不会导致土壤退化。Abstract: A long term study was conducted on the soil and water conservation as well as the nutrient cycling in the juvenile, middle aged and pre matural Chinese fir plantation located in three forest farms attached to the Subtropical Forestry Experimental Center, Chinese Academy of Forestry (CAF) in Fenyi County of Jiangxi Province from 1984 to 1996.The results showed that the degree of soil erosion and nutrient loss occurred in Chinese fir plantation decreased with the increase of plantation age from juvenile to middle aged and to pre mature ones.For example, in the juvenile plantation the surface runoff was 546.0 m3·hm-2, soil loss was 1005.0 kg·hm-2, while in the middle aged plantation the surface runoff was 506.98 m3·hm-2, the soil loss was only 180.7 kg·hm-2 and in the pre mature plantation the surface runoff was 477.25 m3·hm-2,the soil loss was almost zero.For the nutrient loss, the loss of organic mater and the total loss of N, P, K were 50.049 kg·hm-2 and 31.508 kg·hm-2 in the juvenile plantation, 6.080 kg·hm-2 and 2.096 kg·hm-2 in the middle aged plantation, and 10.784 kg·hm-2 in the pre mature plantation.In the juvenile plantation, the soil loss occurred in maximum amount during the first year when the plantation was established and decreased year by year and came to an extremely little amount 4 years after the plantation establishment.For the surface runoff, it seemed no signiflcant relation to the plantation age.In the plantation with soil derived from slate, it had stronger resistance against soil erosion.However, during the whole rotation of Chinese fir plantation in 25 years, the total loss of soil or nutrient was very little, with accumulated amount of 1530.23 m3·hm-2 of surface runoff, 1185.7 kg·hm-2 of soil loss, 56.28 kg·hm-2 of organic mater and 44.383 kg·hm-2 of N, P, and K nutrients.K lost the most among all kind of nutrient elements.It was concluded that there would be no soil degradation in the Chinese fir plantation grown and managed at the site with soil derived from slate.