Sun Li-Juan, Zeng Hui, Guo Da-Li
Shenzhen Key Laboratory of Recycling Economy, Shenzhen Graduate School, Peking University, Shenzhen 518055, Guangdong, China.
Ying Yong Sheng Tai Xue Bao. 2011 Dec;22(12):3087-93.
In July-December 2010, a complete factor-controlled experiment was conducted to study the effects of litter and mineral nitrogen addition on soil organic matter decomposition (soil respiration) at the depths of 0-10 cm and 20-30 cm in Dinghu Mountain National Reserve. Coniferous needle litter and broadleaved litter were added, respectively, and 70 g N x m(-2) x yr(-1) of NH4 NO3 was applied to simulate soil nitrogen saturation whereas soil mineral nitrogen was removed by ion-exchange membrane to simulate the decreased nitrogen absorption by root. The addition of both needle litter and broadleaved litter increased the respiration rate of soil-litter system significantly from July to November, but this effect disappeared in December. Both mineral nitrogen application and soil mineral nitrogen removal increased the soil-litter respiration significantly. These results suggest that litter decomposed completely in a short period therefor had limited effects on soil organic matter decomposition and accumulation, and thus, foliar litters could be not the major source of soil organic matter, whereas soil mineral nitrogen removal could obviously promote the soil organic matter decomposition in the system.
2010年7月至12月，在鼎湖山国家级自然保护区进行了一项完全因子控制实验，以研究添加凋落物和矿质氮对0 - 10厘米和20 - 30厘米深度土壤有机质分解（土壤呼吸）的影响。分别添加针叶凋落物和阔叶凋落物，并施入70克氮每平方米每年的硝酸铵以模拟土壤氮饱和，同时通过离子交换膜去除土壤矿质氮以模拟根系氮吸收减少。从7月到11月，针叶凋落物和阔叶凋落物的添加均显著提高了土壤 - 凋落物系统的呼吸速率，但这种效应在12月消失。施用矿质氮和去除土壤矿质氮均显著增加了土壤 - 凋落物呼吸。这些结果表明，凋落物在短期内完全分解，因此对土壤有机质分解和积累的影响有限，所以，叶片凋落物可能不是土壤有机质的主要来源，而去除土壤矿质氮明显促进了系统中土壤有机质的分解。
