【摘要】 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。更多还原

【Abstract】 The effect of nitrogen addition on decomposition of Chinese fir leaf litter and soil nutrient leaching was studied in situ using a self designed lysimeter. The addition of nitrate significantly (p =0 05) increased weight loss leaf litter by 10% above non addition of N (control) and addition of ammonium treatments. The addition of ammonium had no effect relative to the control treatment.The addition of nitrate or ammonium had a negative effect on soil nutrient leaching. Leaching of NH 4 + N and Ca 2+ increased under the +L+NO 3 treatment when compared with the +L N treatment, but no significant differences were detected (p>0 05). The addition of ammonium substantially increased the leaching of all base cations measured, with the exception of Na +. The amount of nutrient elements increased whilst the soil was covered with Chinese fir leaf litter compared with the bare soil when leached with distilled water, but this effect was not significant (p>0 05). Calcium was the most easily leached of all the nutrient elements.更多还原