黄土高原子午岭林区主要林分生态化学计量学特征

Ecological Stoichiometric Characteristics of Main Forest Stands in Ziwuling Forest Region on the Loess Plateau, China

论文以黄土高原子午岭林区4种林分(侧柏、油松、辽东栎、刺槐)的绿叶、凋落物(凋落叶、枯枝、果实)为研究对象,分析其C、N、P含量及化学计量学特征,并计算养分再吸收率,为黄土高原植被恢复建设及人工林合理种植规划提供理论依据。结果显示:植物叶片凋落前N、P均发生营养转移,油松N养分再吸收率最高(44.73%),刺槐P养分再吸收率最高(41.10%);刺槐相比于其他3种林分,绿叶C含量(413.94 g·kg^(-1))略低,且其4个组分N含量略高于其他林分的相应组分,绿叶、果实P含量相对较高;4种林分的枯枝C∶N、C∶P值最大,碳蓄积功能较强;叶片N∶P值均小于14,表明生长旺盛期林分主要受N限制。油松、刺槐养分再吸收能力强,是黄土高原森林区适宜植被恢复的造林树种。

To analyze carbon（C）, nitrogen（N）, phosphorus（P） and ecological stoichiometric characteristics in green leaf, litter, dead branch and fruit, four forest stands of different species（Platycladus orientalis, Pinus tabuliformis, Quercus wutaishanica and Robinia pseudoacacia L） in Ziwuling forest area on Loess Plateau were collected. The C, N, P contents and C∶N, C∶P, N∶P ratios were measured, and the variations of them were explored in the four forest stands.The results showed that N, P contents of plant were transferred before plant leaf withering and falling, and the resorption efficiencies of various nutrient elements were different. In this study,the highest resorption efficiency of N nutrient was 44.73%（Pinus tabuliformis）, the highest resorption efficiency of P nutrient was 41.10%（Robinia pseudoacacia L）, respectively. In addition, in Ziwuling forest area, the C content of green leaf under Robinia pseudoacacia L forest was 413.94 g·kg-（-1）, which was a little lower than that of other forest stands. However, the N contents of green leaf, litter, dead branch and fruit under Robinia pseudoacacia L forest were29.74, 17.10, 8.59, and 24.79 g · kg-（-1）, which were slightly higher than the corresponding components of other forest stands; the P contents of green leaf and fruit under Robinia pseudoacacia L forest were 2.43 and 2.53 g · kg^-1, which were higher than the corresponding components of other forest stands. The carbon accumulation capacities of these four forest stands were large. The resorption efficiencies of Pinus tabuliformis and Robinia pseudoacacia L were greater than that of Quercus wutaishanica and Platycladus orientalis. The C∶N, C∶P and N∶P ratios indicated that C accumulation was strong and that N, P nutrient were restricted by its ecosystem condition. The C∶N, C∶P ratios in dead branch were higher than the ratios in other components of the four species of plants. The N∶P ratios in green leaf of the four forest stands were all smaller than 14, showing that carbon accumulation capacity of dead branch was strong and the growth of the four forest stands were limited by N. This study found that Pinus tabuliformis and Robinia pseudoacacia L were more suitable for forest vegetation restoration on the Loess Plateau, China.