华蓥市山区典型林分土壤团聚体稳定性及抗蚀能力

  目的  探究四川省华蓥市典型林分下土壤团聚体稳定性变化特征及其影响因素，为阐明该地区团聚体组成及其稳定性机制提供理论依据。  方法  选取华蓥市山区5种典型林分(柏木Cupressus funebris纯林、杉木Cunninghamia lanceolata纯林、马尾松Pinus massoniana-檵木Loropetalum chinense混交林、马尾松-杉木混交林、近自然经营杉木纯林)为研究对象，通过测定林分表层(0~15 cm)和亚表层(15~30 cm)土壤理化性质，分析土壤理化性质对团聚体变化特征和土壤抗蚀性的影响。  结果  ①5种典型林分土壤大团聚体质量百分比为77%~93%，且不同林分间平均质量直径(MWD)和土壤可蚀性存在显著差异(P＜0.05)，其平均质量直径柏木林最大(2.33 mm)，马尾松-檵木混交林最小(1.53 mm)。土壤可蚀性从大到小依次为近自然经营杉木纯林、柏木林、杉木纯林、马尾松-杉木混交林、马尾松-檵木混交林。②冗余分析表明:速效钾、土壤总孔隙度和土壤有机碳与平均质量直径呈显著正相关(P＜0.05)，与土壤可蚀性呈显著负相关(P＜0.05)；土壤容重与平均质量直径呈显著负相关性(P＜0.05)，与土壤可蚀性呈显著正相关(P＜0.05)。  结论  5种典型林分中，柏木林和近自然经营杉木纯林土壤水稳性团聚体最稳定、抗侵蚀性强，马尾松-檵木混交林土壤水稳性团聚体稳定性最低。传统经营模式下柏木林地土壤团聚体更稳定，土壤抗蚀性更强；近自然经营模式有利于土壤团聚体稳定性和土壤抗蚀性的提高。图3表3参32

Soil aggregate stability and anti-erodibility of typical forest stands in Huaying mountain area

  Objective  The objective of this study is to explore the characteristics and influencing factors of soil aggregate stability under typical forest stands in Huaying City, Sichuan Province, so as to provide theoretical basis for elucidating the composition and stability mechanism of soil aggregates in this area.  Method  Five typical stands (Cupressus funebris pure forest, Cunninghamia lanceolata pure forest, Pinus massoniana-Loropetalum chinense mixed forest, P. massoniana-C. lanceolata mixed forest, and near natural C. lanceolata pure forest) were selected as the research objects. The soil physical and chemical properties of the surface layer (0?15 cm) and subsurface layer (15?30 cm) of the stands were measured to analyze the effects on aggregate change characteristics and soil erosion resistance.  Result  (1) The contents of soil macroaggregates in five typical stands were 77%?93%, with significant differences in mean weight diameter (MWD) and soil erodibility (K) among different stands (P＜0.05). The MWD value of C. funebris forest was the largest (2.33 mm, and that of P. massoniana-L. chinense mixed forest was the smallest(1.53 mm). The K values of soil erodibility from large to small followed the order of near natural C. lanceolata pure forest, C. funebris forest, C. lanceolata pure forest, P. massoniana-C. lanceolata mixed forest, and P. massoniana-L. chinense mixed forest. (2) Redundancy analysis (RDA) showed that available potassium, total porosity and organic carbon were significantly positively correlated with MWD and negatively correlated with K value, and soil bulk density was significantly negatively correlated with MWD and positively correlated with K value.  Conclusion  Among the five typical stands, C. funebris and near natural C. lanceolata pure forest have the highest stability of soil water stable aggregates and strong erosion resistance, while P. massoniana-L. chinense mixed forest displays the lowest stability of soil water stable aggregates. Under the traditional management mode, the soil aggregate of C. funebris is more stable and soil anti-erodibility is stronger. The near natural management mode is conducive to the improvement of soil aggregate stability and soil anti-erodibility. Ch, 3 fig. 3 tab. 32 ref.]