不同沙生植被土壤易氧化有机碳组分及其含量的差异

以9种沙生植被为研究对象,沙裸地为对照,采用野外调查与室内分析相结合的方法,分析不同沙生植被土壤易氧化有机碳(C_oc)各组分的变化特征,并在此基础上提出土壤有机碳活性系数和敏感指数,探讨不同沙生植被对改善土壤质量的影响。结果表明:沙裸地种植植被后,C_oc各组分和总有机碳(C_toc)含量显著增加,但C_oc各组分占C_toc的比例无明显变化;与其他沙生植被相比,刺槐林(Robinia pseudoacacia)、花棒(Hedysarum scoparium)、臭柏(Sabina vulgaris)和樟子松(Pinus sylvestris var.mongolica)对改善土壤质量,提高土壤有机碳活性的作用更加显著。敏感指数表明C_oc中第1部分(C_frac1)和第2部分(C_frac2)活性较强,其中C_frac1对土壤质量变化更加敏感,可以作为衡量土壤质量状况的良好指标。相关性分析表明C_frac1,C_frac2,C_frac3,C_frac4,C_oc与C_toc之间极显著相关 (P<0.01),与碱解氮和全氮成显著或极显著正相关(P<0.05或P<0.01),与全磷和速效磷之间的相关关系不显著,C_frac4和C_toc与速效钾之间极显著正相关(P<0.01),C_frac1,C_frac2,C_frac4,C_oc,C_toc与pH成显著或极显著负相关(P<0.05或P<0.01)。综上所述,C_frac1可作为衡量土壤质量状况的良好指标,刺槐、花棒、臭柏和樟子松这4种植物可作为毛乌素沙地改善土壤质量的优先考虑植被。

Variation Characteristics and Fractions of Oxidizable Organic Carbon in Different Sandy Vegetation Soil

The variation and fractions of oxidizable organic carbon (C_oc) from nine psammophytes were studied through field investigation and laboratory analysis. Soil sensitive index and the influence of different vegetations on soil quality improvement were also discussed. Results showed that the contents of C_oc and total organic carbon (C_toc) increased significantly by planting on bare sand, whereas the percentage of C_oc to C_toc had no change. Robinia pseudoacacia (RP), Hedysarum scoparium (HS), Sabina vulgaris (SV) and Pinus sylvestris var.mongolica (PS) improved soil quality and carbon activity more significantly compared with other vegetations. Sensitive index showed that the first (C_frac1) and second fraction (C_frac2) of C_oc had high activity, C_frac1 was more labile than C_frac2 and can be used to evaluate soil quality. Correlation analysis showed that there was a significant relationship among C_frac1, C_frac2, C_frac3, C_frac4, C_oc and C_toc (P<0.01), and they were positively correlated with available N and total N (P<0.05), but not correlated with total P and available P. Additionally, C_frac4 and C_toc were positively correlated with available P (P<0.01). There was a negative correlation between C_frac1, C_frac2, C_frac4, C_oc, C_toc and pH value (P<0.01 or P<0.05). In conclusion, C_frac1 can be used as a favorable indicator for soil quality evaluation. Robinia pseudoacacia (RP), Hedysarum scoparium (HS), Sabina vulgaris (SV), and Pinus sylvestris var.mongolica (PS) can be considered as preferential choice for soil quality restoration in Muus sandland.