College of Forestry, Hebei Agricultural University, Baoding, 071000, China.
Hebei Saihanba Mechanized Forest Farm, Chengde, 067000, China.
Sci Rep. 2024 Aug 28;14(1):20022. doi: 10.1038/s41598-024-71162-3.
Different vegetation restoration methods have improved soil quality to varying degrees. This study, focused on the forest-grassland-desert transition zone in the Hebei-Inner Mongolia border region, and employed a systematic grid sampling method to establish fixed monitoring plots in the Saihanba Mechanized Forest Farm and the Ulan Buh Grassland. The differences in soil quality evolution across various vegetation restoration methods under the same climatic and soil historical conditions were analyzed, elucidating the roles of these vegetation restoration methods in degraded forest ecosystems, with the aim of providing a reference for ecological restoration under similar land conditions. This study used a grid method to establish sample points in the forest-grassland-desert transitional zone and assessed five methods of vegetation restoration sites: artificial forest composed of native species of Larix principis-rupprechtii (FL), artificial forest composed of exotic Pinus sylvestris var. mongolica (FP), natural secondary broad-leaved forest (FN), open grassland (GO), and enclosed grassland (GC). The differences in soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkaline hydrolysis nitrogen (AN), rapidly available phosphorus (AP) and rapidly available potassium (AK) among the different vegetation restoration sites were compared via variance analysis, and the soil quality index (SQI) was calculated to assess the soil quality at the sample points. The SOC, TN, and AN contents of forest soil were significantly greater than those of grassland, and the TN, TP, AN, AK, and SOC contents of FL, FN, and GC were significantly greater than those of FP and GO. Among them, the TN, TP, and SOC contents were the highest in the FL, reaching 2.74, 0.39, and 47.27 g kg, respectively. In terms of ecological stoichiometric characteristics, the average N:P ratio in the study area was 6.68, indicating a serious lack of N in the study area. Among the different types of restoration sites, the effect was stronger in the FP than in the FL, and the TN and AN contents were only 1.48 g kg and 116.69 mg kg, respectively. The SQI in the FL was not significantly different from that in the FN or GC, but it was significantly greater than that in the FP and GO. These findings indicate that native tree species restoration in degraded forest ecosystems significantly improved soil quality, while the introduction of exotic tree species for afforestation had a minimal effect on improving soil quality.
不同的植被恢复方法在不同程度上改善了土壤质量。本研究以河北-内蒙古交界地区的森林-草原-荒漠过渡带为研究对象，采用系统网格采样法，在塞罕坝机械化林场和乌兰布和草原建立固定监测样地，分析了同一气候和土壤历史条件下不同植被恢复方法对土壤质量演变的差异，阐明了这些植被恢复方法在退化森林生态系统中的作用，为类似土地条件下的生态恢复提供参考。本研究采用网格法在森林-草原-荒漠过渡带建立样点，评估了五种植被恢复地点的方法：由乡土树种落叶松（Larix principis-rupprechtii）组成的人工林（FL）、由外来树种樟子松（Pinus sylvestris var. mongolica）组成的人工林（FP）、天然次生阔叶林（FN）、开放草地（GO）和封闭草地（GC）。通过方差分析比较不同植被恢复地点之间土壤有机碳（SOC）、总氮（TN）、总磷（TP）、总钾（TK）、碱解氮（AN）、速效磷（AP）和速效钾（AK）的差异，并计算土壤质量指数（SQI）评估样点的土壤质量。林地土壤的 SOC、TN 和 AN 含量显著高于草地，FL、FN 和 GC 的 TN、TP、AN、AK 和 SOC 含量显著高于 FP 和 GO。其中，FL 的 TN、TP 和 SOC 含量最高，分别达到 2.74、0.39 和 47.27 g kg-1。在生态化学计量特征方面，研究区平均 N:P 比为 6.68，表明研究区 N 严重缺乏。在不同类型的恢复地点中，FP 的效果强于 FL，TN 和 AN 含量分别仅为 1.48 g kg-1 和 116.69 mg kg-1。FL 的 SQI 与 FN 或 GC 无显著差异，但明显大于 FP 和 GO。这些发现表明，在退化森林生态系统中，乡土树种恢复显著改善了土壤质量，而引入外来树种造林对改善土壤质量的作用较小。
