不同类型盐碱土有机碳及微生物生物量碳的垂直分布特征

Vertical distribution patterns of organic carbon and microbial biomass carbon in different types of saline-alkali soil

基于新疆6种主要盐碱土类型的资料,研究了新疆主要盐碱土有机碳(SOC)和微生物生物量碳(MBC)的分布特征,探讨了其与环境因子的关系。结果表明:SOC在不同类型盐碱土中的大小顺序为纯苏打(CSD)>氯化物-硫酸盐(L-LS)>硫酸盐-氯化物(LS-L)>苏打(SD)>硫酸盐(LS)>氯化物(L);除LS和SD、SD和LS-L两两之间SOC没有显著差异外,其他各盐碱土类型之间均存在显著差异(P<0.05);在垂直剖面上,各盐碱土SOC都随着土层深度的增加而表现出降低的趋势,并存在明显的分层特征;随着土壤盐碱类型和植被类型的变化,MBC在不同类型盐碱土中的大小顺序依次为CSD>LS>L-LS>SD>LS-L>L;除L-LS和SD之间没有显著差异外,其他各盐碱土类型之间MBC含量均存在显著差异(P<0.05);不同类型盐碱土的MBC差别较大,且与SOC含量大小并不一致,可能是微生物需要的生境和食性特征不一样决定的;同一盐碱土类型内,MBC剖面具有显著的分层特征。MBC随深度的增加而显著减少,其递减率在不同盐碱土类型之间存在明显差异;MBC与土壤含水量、土壤容重的关系并不像一般的研究结果认为具有显著的线性相关关系,未表现出明显的规律性。

Based on the investigation data of six main types of saline-alkali soil in Xinjiang of Northwest China, this paper analyzed the spatial distribution patterns of organic carbon （OC） and microbial biomass carbon （MBC） in these soils, and explored the relationships between the soil OC and MBC and environmental factors. The OC content in the soils was in the order of pure soda （CSD） 〉 chloride-sulfate （L-LS） 〉 sulfate-chloride （LS-L） 〉 soda （SD） 〉 sulfate （LS） 〉 chloride （ L）, and significant difference （ P 〈 0.05 ） was observed among the different types of saline-alkali soil, with the exception between LS and SD, and between SD and LS-L. The OC content in the soils decreased with depth, and had obvious stratification characteristics. Similar- ly, the MBC in the soils was in the order of CSD 〉 LS 〉 L-LS 〉 SD 〉 LS-L 〉 L, and significant difference （P 〈 0.05 ） was existed among the different types of saline-alkali soil, with the excep- tion between L-LS and SD. The MBC in the soils had a great difference, and was not in accord- ance with the OC content, which could be explained by the differences in the habitat and feedingpattern of soil microbes. In a given soil type, MBC also had obvious stratiiication characteristics. The MBC decreased sharply with soil depth, and the decrement varied with soil types. Not as previously reported, the soil MBC in this study had no linear relationships with soil moisture con- tent and soil bulk density.