论文部分内容阅读
土壤活性有机碳组分对土地利用变化的响应规律已成为当前土壤碳和养分循环研究的一个热点.本文以黄土丘陵子午岭林区为研究区,通过分析天然乔木林转变为人工乔木林、天然乔木林转变为农田,天然灌木林转变为农田以及撂荒后土壤活性有机碳含量及其在土壤剖面上分布的差异,与浅层(0~60 cm)土壤对比,分析土地利用变化对深层土壤(60~200 cm)活性有机碳组分的影响.结果表明:1土壤易氧化性碳(LOC)和土壤微生物量碳(MBC)含量主要集中在0~60 cm土层,分别占0~200 cm土层含量的49%~66%和71%~84%.不同土地利用类型0~60 cm土层LOC和MBC含量差异显著,深层土壤含量差异不显著.2土地利用变化对土壤活性有机碳影响显著,浅层比深层反映敏感.天然乔木林转变成人工乔木林和农田、天然灌木林转变成撂荒地和农田这4种土地利用转变方式下,浅层土壤LOC分别减少了10%、60%、29%、40%,深层分别减少了9%、21%、12%、1%;浅层土壤MBC分别减少了24%、73%、23%、56%,深层土壤MBC分别减少了25%、18%、8%、11%.3土地利用变化改变了活性有机碳占总有机碳的分配比例.天然乔木林和天然灌木林转变成农田浅层土壤LOC/SOC比例增加,深层差异不大;天然灌木林转变为农田,浅层土壤MBC/SOC降低,深层差异不大.结果说明土壤活性有机碳含量和分配比例受土地利用变化的影响,与浅层相比,深层土壤有机碳具有较大的稳定性.
The response of soil active organic carbon components to land use change has become a hot spot in the research of current soil carbon and nutrient cycling.In this paper, the study area of Ziwuling mountain forest area is selected as the study area, and natural arbor forest is transformed into artificial arbor forest. Natural Compared with the shallow soil (0 ~ 60 cm), the change of active organic carbon and the distribution of soil active organic carbon after the conversion of arbor forest into farmland and natural shrub forest to abandoned farmland were analyzed. The effects of land use change on soil depth 60 ~ 200 cm). The results showed that: (1) The contents of LOC and MBC mainly concentrated in 0 ~ 60 cm soil layer, accounting for 0 ~ 200 cm 49% -66% and 71% -84% of the soil layer.The content of LOC and MBC in 0-60 cm soil layer of different types of land use is significantly different, while the difference of soil depth is not significant.2 The effect of land use change on soil active organic carbon Significantly, the shallow layer is more sensitive than the deep layer.Under the transformation of natural arbor forest into artificial arbor forest and farmland, natural shrubbery into fallow land and farmland, the LOC of shallow soil decreased by 10% and 60% , 29%, 40%, The soil MBC decreased by 24%, 73%, 23% and 56% in the shallow soil layer, and decreased by 25%, 18% and 8% in the deep soil layer, 11% .3 Changes in land use changed the distribution of active organic carbon (TOC) in total organic carbon (DOC). The ratios of LOC / SOC in the shallow soils transformed from natural and natural shrubs to farmland increased with little difference in depth; , And the MBC / SOC in shallow soil decreased with little difference in deep layer.The results indicated that the content and distribution proportion of active organic carbon in soil were affected by land use change, and soil organic carbon in deep soil had greater stability than shallow soil.