Zeng Quanchao, Lal Rattan, Chen Yanan, An Shaoshan
College of Natural Resources and Environment, Northwest A&F University, Yangling, P.R. China.
Carbon Management and Sequestration Center, The Ohio State University, Columbus, Ohio, United States of America.
PLoS One. 2017 Jan 11;12(1):e0168890. doi: 10.1371/journal.pone.0168890. eCollection 2017.
Caragana korshinskii, a leguminous shrub, a common specie, is widely planted to prevent soil erosion on the Loess Plateau. The objective of this study was to determine how the plantation ages affected soil, leaf and root nutrients and ecological stoichiometry. The chronosequence ages of C. korshinskii plantations selected for this study were 10, 20 and 30 years. Soil organic carbon (SOC) and soil total nitrogen (STN) of C. korshinskii plantations significantly increased with increase in the chronosequence age. However, soil total phosphorous (STP) was not affected by the chronosequence age. The soil C: N ratio decreased and the soil C: P and N: P ratios increased with increasing plantation age. The leaf and root concentrations of C, N, and P increased and the ratios C: N, C: P, and N: P decreased with age increase. Leaf N: P ratios were >20, indicating that P was the main factor limiting the growth of C. korshinskii. This study also demonstrated that the regeneration of natural grassland (NG) effectively preserved and enhanced soil nutrient contents. Compared with NG, shrub lands (C. korshinskii) had much lower soil nutrient concentrations, especially for long (>20 years) chronosequence age. Thus, the regeneration of natural grassland is an ecologically beneficial practice for the recovery of degraded soils in this area.
柠条锦鸡儿是一种豆科灌木，是一种常见物种，在黄土高原广泛种植以防止土壤侵蚀。本研究的目的是确定种植年限如何影响土壤、叶片和根系养分以及生态化学计量。本研究选择的柠条锦鸡儿人工林的时间序列年龄为10年、20年和30年。柠条锦鸡儿人工林的土壤有机碳（SOC）和土壤全氮（STN）随时间序列年龄的增加而显著增加。然而，土壤全磷（STP）不受时间序列年龄的影响。随着种植年限的增加，土壤C:N比降低，土壤C:P和N:P比增加。随着年龄的增长，叶片和根系中C、N和P的浓度增加，C:N、C:P和N:P比降低。叶片N:P比>20，表明P是限制柠条锦鸡儿生长的主要因素。本研究还表明，天然草地（NG）的恢复有效地保持并提高了土壤养分含量。与NG相比，灌木林地（柠条锦鸡儿）的土壤养分浓度要低得多，尤其是对于时间序列年龄较长（>20年）的情况。因此，天然草地的恢复是该地区退化土壤恢复的一种生态有益做法。
