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以黄土高原沟壑区王东沟小流域为对象,研究了地形(塬面、塬坡和沟道)、土地利用(自然草地、人工草地、人工林地、农地和果园)对0～200cm土层内土壤有机碳(soil organic carbon,SOC)垂直分布特征的影响,以揭示黄土高原小流域深层SOC储量及其影响因素.结果表明,SOC含量除表层(0～20cm)沟道(10.0g·kg-1)大于塬面(7.8g·kg-1)和塬坡(8.2g·kg-1)外,塬面底层SOC均显著高于塬坡和沟道;塬坡和沟道SOC含量随深度增加而降低,而塬面上呈现SOC随深度增加降低-升高-降低的变化趋势.塬面上,SOC含量呈现人工草地(5.4g·kg-1)>农田(5.2g·kg-1)和果园(5.1g·kg-1)的趋势,影响深度为表层40cm;塬坡上,呈现自然草地(4.3g·kg-1)>人工林地(3.8g·kg-1)>人工草地(3.3g·kg-1)和果园(3.3g·kg-1)的趋势,影响深度达到100cm;而沟道内,林草地利用方式对整个垂直剖面分布的差异无显著影响.20～100cm土层SOC储量占0～100cm储量的67.6%;100～200cm土层SOC储量占0～200cm储量的37.3%,相当于0～100cm的63.8%.研究结果表明地形、土地利用显著(p<0.05)影响SOC垂直分布特征;黄土高原沟壑区深层SOC储量巨大,不容忽视.
Taking Wangdonggou watershed in the gully area of the Loess Plateau as an example, the effects of land use (natural grassland, artificial grassland, plantation land, farmland and orchard) on the topsoil of 0 ~ 200cm soil layer (SOC) in the Loess Plateau to reveal the SOC abundance and its influencing factors in the small watershed of the Loess Plateau.The results showed that the SOC content in the topsoil (0-20 cm) channel (10.0 g · kg -1) -1) were higher than those on the plateau (8.2 g · kg-1) and 7.8 g · kg-1 on the plateau, while SOC in the plateau and channel was significantly higher with depth (SOC) of artificial grassland (5.4g · kg-1)> 5.2g · kg-1 (farmland) on the plateau, (4.3 g · kg-1)> Artificial forest (3.8 g · kg-1)> artificial grassland (3.3 g · kg-1) and orchard (5.1 g · kg-1) g · kg-1 and orchard (3.3g · kg-1), and the depth of influence reached 100cm. However, the use of forest and grassland in the channel had no significant effect on the distribution of the entire vertical profile. The SOC of 20 ~ 100cm soil layer 0 ~ 100cm reserves 67.6% of the total SOC, accounting for 37.3% of the 0-200 cm stock in the 100-200 cm soil layer, equivalent to 63.8% of 0-100 cm. The results show that the terrain and land use significantly (p <0.05) affect the vertical distribution of SOC and the Loess Plateau gully Area deep SOC reserves huge, can not be ignored.