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采用原位 (In situ)模拟实验方法研究了外加 N源对杉木叶凋落物分解及土壤养分淋失的影响 ,结果表明 :施加 NH4+ - N时 ,杉木叶凋落物的失重率与对照 (未加任何 N的处理 )相比 ,没有差异 ;而施加 NO3- - N时 ,使杉木叶凋落物分解速率显著提高 (p=0 .0 5 ) ,达 10 %以上。与施加 NH4+ - N相比 ,施加 NO3- - N明显促进了杉木叶凋落物的分解 (p=0 .0 5 )。施加 NH4+ - N和 NO3- - N会产生负作用 ,使土壤养分淋失。在土壤表面覆盖杉木叶凋落物的同时施加 NO3- - N的处理比只覆盖杉木叶凋落物的处理 ,NH4+ - N和 Ca2 + 的淋失有所增加 ,但并不明显 (p=0 .0 5 )。施加 NH4+ - N使NO3- - N的淋失明显增多 ,因为提供更多的硝化 N源 ;除 Na+以外 ,施加 NH4+ - N使其它盐基阳离子淋失明显增多。土壤表面覆盖杉木叶凋落物但只用蒸馏水淋洗比直接淋洗裸露土表使所有养分元素的淋失都有所增多 ,但并没有显著差异 (p=0 .0 5 )。Ca2 + 的淋失在各种处理下是所有养分元素中最多的。
The effects of N sources on litter decomposition and soil nutrient leaching of Chinese fir were investigated by in situ simulation. The results showed that the weight loss rate of litter in Chinese fir was decreased with the increase of NH4 + - N N treatment). However, NO3- - N significantly increased litter decomposition rate of Chinese fir (p = 0.05), up to 10%. Compared with the application of NH4 + - N, the application of NO3- - N obviously promoted the decomposition of Chinese fir leaf litter (p = 0.05). The application of NH4 + -N and NO3- - N will have a negative effect, leaching soil nutrients. The leaching of NH4 + - N and Ca2 + was not significant (p = 0 .0) when NO3- - N was applied to the surface of the soil while covering litter of Chinese fir, 5). The leaching of NO3- - N significantly increased due to the addition of NH4 + - N because it provided more nitrifying N source. In addition to Na +, the NH4 + - N addition significantly increased leaching of other base salts. Soil surface covered with Chinese fir leaf litter but leached with distilled water only increased the leaching of all nutrient elements more than the direct leaching of bare soil, but with no significant difference (p = .0 5). Leaching of Ca2 + is the largest of all nutrient elements under various treatments.