Characteristics of carbon, nitrogen, and phosphorus in soil aggregates under different restoration methods on cut slopes in the Qinghai-Tibet Plateau mining area

This study systematically compared soil aggregate stability and carbon-nitrogen-phosphorus nutrient characteristics among three restoration methods for cut slopes (three-dimensional netting [TCS], frame beams [FCS], and galvanized wire mesh [GCS]) relative to unrestored cut slopes (UCS) in the Jiama Mining Area, Tibet. Microsoft Excel 2022 was used for data organization, while statistical analyses were conducted with SPSS 20.0. Statistical comparisons of restoration treatments for soil properties (nutrient indicators, enzyme activities) employed one-way ANOVA with Tukey's HSD multiple comparisons.
TCS exhibited significantly higher SOC content than FCS, GCS, and UCS. For aggregates smaller than 0.25 mm, FCS exhibited significantly higher SOC values than other restoration methods. While bulk soil SOC contents were significantly elevated in FCS and TCS compared to GCS and UCS, GCS and UCS did not differ significantly from each other. TCS exhibited significantly higher TN contents in most aggregate size classes compared to other treatments. Among the three restoration methods, only GCS exhibited lower TN contents than UCS across all aggregate size fractions. In bulk soil, TN contents in GCS and UCS showed no significant difference but were both significantly lower than those in TCS and FCS, with TCS also showing significantly higher TN content than FCS. A significant increase in TP content was observed in macroaggregates from TCS and FCS compared with GCS and UCS. Within the microaggregates fraction, TP concentrations were significantly elevated in FCS and UCS relative to TCS and GCS. TP concentrations in the < 0.053 mm fraction were significantly elevated in FCS relative to other treatments. In bulk soil, UCS had the highest TP content, significantly higher than that in TCS and GCS.
TCS exhibited significantly higher soil saccharase (SAC) activity across all aggregate size fractions compared to the other cut slopes. In aggregates smaller than 2 mm, both FCS and GCS exhibited higher SAC activity than UCS. Statistical analysis detected no significant variation in bulk soil SAC activity between GCS and UCS treatments. Both TCS and FCS exhibited higher urease (URE) activity than GCS and UCS. UCS exhibited significantly higher URE activity than GCS only in the microaggregates fraction. TCS exhibited significantly higher alkaline phosphatase (ALP) activity than the other cut slopes. Except in the microaggregates fraction, where FCS, GCS, and UCS showed no significant differences in ALP activity. In bulk soil, ALP activity differed significantly among the four slope types, with the hierarchy: TCS > FCS > GCS > UCS. Across bulk soil and > 0.053 mm aggregates, catalase (CAT) activity was significantly lower in GCS compared to other slope types. TCS demonstrated significantly higher CAT activity than other restoration methods in both bulk soil and < 2 mm aggregates, while FCS and GCS showed no significant difference.

本研究以西藏甲玛矿区的开挖边坡为研究对象，系统对比了三种修复方式——三维网植草护坡（three-dimensional netting, TCS）、框架梁护坡（frame beams, FCS）与镀锌铁丝网护坡（galvanized wire mesh, GCS）——与未修复开挖边坡（UCS）的土壤团聚体稳定性（soil aggregate stability）及碳氮磷养分特征。本研究采用微软Excel 2022进行数据整理，使用SPSS 20.0完成统计分析。针对土壤属性（养分指标、酶活性）的修复处理间统计比较，采用单因素方差分析结合Tukey HSD多重比较检验。
三维网植草护坡的土壤有机碳（soil organic carbon, SOC）含量显著高于框架梁护坡、镀锌铁丝网护坡以及未修复开挖边坡。对于粒径小于0.25 mm的团聚体，框架梁护坡的SOC含量显著高于其他修复方式。与镀锌铁丝网护坡和未修复开挖边坡相比，整体土壤的SOC含量在框架梁护坡和三维网植草护坡中显著提升，而镀锌铁丝网护坡与未修复开挖边坡的SOC含量无显著差异。三维网植草护坡在多数粒径级别的团聚体中全氮（total nitrogen, TN）含量显著高于其他处理。在三种修复方式中，仅镀锌铁丝网护坡在所有团聚体粒径分级中的TN含量均低于未修复开挖边坡。整体土壤中，镀锌铁丝网护坡与未修复开挖边坡的TN含量无显著差异，但二者均显著低于三维网植草护坡和框架梁护坡，且三维网植草护坡的TN含量也显著高于框架梁护坡。大团聚体中的全磷（total phosphorus, TP）含量在三维网植草护坡和框架梁护坡中显著高于镀锌铁丝网护坡和未修复开挖边坡。在微团聚体组分中，框架梁护坡和未修复开挖边坡的TP浓度显著高于三维网植草护坡和镀锌铁丝网护坡。粒径小于0.053 mm组分的TP浓度在框架梁护坡中显著高于其他处理。整体土壤中，未修复开挖边坡的TP含量最高，显著高于三维网植草护坡和镀锌铁丝网护坡。
三维网植草护坡在所有粒径级别的团聚体中土壤蔗糖酶（saccharase, SAC）活性均显著高于其他开挖边坡修复方式。在粒径小于2 mm的团聚体中，框架梁护坡和镀锌铁丝网护坡的蔗糖酶活性均高于未修复开挖边坡。统计分析显示，整体土壤的蔗糖酶活性在镀锌铁丝网护坡与未修复开挖边坡间无显著差异。三维网植草护坡和框架梁护坡的脲酶（urease, URE）活性均高于镀锌铁丝网护坡和未修复开挖边坡。仅在微团聚体组分中，未修复开挖边坡的脲酶活性显著高于镀锌铁丝网护坡。三维网植草护坡的碱性磷酸酶（alkaline phosphatase, ALP）活性显著高于其他开挖边坡修复方式。除微团聚体组分外，框架梁护坡、镀锌铁丝网护坡与未修复开挖边坡的碱性磷酸酶活性无显著差异。整体土壤中，四种边坡类型的碱性磷酸酶活性存在显著差异，排序为：三维网植草护坡 > 框架梁护坡 > 镀锌铁丝网护坡 > 未修复开挖边坡。在整体土壤和粒径大于0.053 mm的团聚体中，镀锌铁丝网护坡的过氧化氢酶（catalase, CAT）活性显著低于其他边坡类型。三维网植草护坡在整体土壤和粒径小于2 mm的团聚体中的过氧化氢酶活性均显著高于其他修复方式，而框架梁护坡与镀锌铁丝网护坡间无显著差异。