中图分类号：S153 文献标识码：A 文章编号：1007-0435（2025）07-2219-08

引用格式：，等.荒漠草原土壤碳分布特征及有机碳向无机碳酸盐的转移[J].草地学报，2025，33（7）： 2219-2226 WANG Xue-ren，YAO Jia，ZHANG Pu-he，et al.Characteristicsof Soil Carbon Distribution and Transferof Organic Carbon to Inorganic Carbonate in Desert Steppe[J].Acta Agrestia Sinica，2025，33（7） ：2219-2226

Abstract：In this study，the desert steppe in Siziwangqi，Inner Mongolia wasused as the studyarea to investi gate the vertical distribution characteristics of soil carbon，and the stable carbon isotope technique Was used to differentiate lithogenic carbonate（LC） and pedogenic carbonate（PC），to quantify the amount of fixed CO₂ and the proportion of the source in the formation process of PC，and finally to quantify the transfer of SOC to SIC. The results showed that in the plant growth period， the SOC content in the soil was 3.38-10.84g⋅kg^-1 and3.44～12.28g⋅kg^-1 ，respectively，and both of them showed a decreasing trend with the deepening of the soil layer；the carbonate content in the soil was 28.14-189.61 g⋅kg^-1 and 27.47-192.13g⋅kg^-1 ，showing an increasing and then decreasing trend with the deepening of the soil layer.During the plant growth period，the PC content in the soil layers of 40-60cm ， 60-80cm and 80-100 cm were 82.40，and 25.44g⋅kg^-1 ，the amount of fixed CO₂ was 18.13，24.87 and 5.60g⋅kg^-1 ;and the proportion of soil respiration from the source was 56. 91% ，51. 91% ，and 65.91% ，respectively. Soil respiration released CO₂ was the main contribution. Finally，the amount of SOC transferred to carbonate in the three soil layers was calculated to be 5.16，6.46， and 1.84g⋅kg^-1 . This study had a preliminary investigation of carbon transfer and provided a theoretical basis for subsequent research on the“carbon cycle”.

Key words：Soil carbon;Stable isotope;Profile characterization;Pedogenic carbonate;Carbon transfer

土壤碳库包括土壤有机碳（Soilorganiccarbon，SOC）和土壤无机碳（Soilinorganiccarbon，SIC），是陆地生态系统中最大且周转时间最长的碳库[1。王壤碳库既是维系地球生物化学循环的重要介质，同时也在维持陆地生态系统结构、分布和功能方面起到重要作用[2]，其含量极低的变动也会引起全球气候的巨大变化[3]。然而，以往的研究多集中于SOC^[4-5] ，而忽视了SIC在碳循环中的作用。土壤无机碳主要是指土壤碳酸盐，而碳酸盐根据其成因可分为原生碳酸盐（Lithogeniccarbonate，LC）和次生碳酸盐（Pedogeniccarbonate，PC）[6]。其中，次生碳酸盐是指土壤风化成土过程中形成的碳酸盐，其与原生碳酸盐的溶解及沉积平衡过程密切相关，在全球碳固持中起到重要作用。近年来，有研究者发现在干旱荒漠地区无机碳存在稳定的“碳汇\"现象，因此土壤无机碳库开始被更多的关注。

草地生态系统是陆地碳循环、碳截储的重要组成部分，全球草地生态系统碳储量约占全球陆地生态系统碳储量的 15.2% 。在我国，草原土壤无机碳库主要分布在北部及西北十旱地区草原和灌丛植被下[8]。内蒙古荒漠草原位于我国北部地区，因其气候干燥，较高的海拔及独特的成土母质等原因使得土壤内含有大量的无机碳酸盐[9]。土壤内碳酸盐存在一个溶解一沉淀一再结晶的动态变化过程。在植物生长期内，植物的呼吸速率及有机碳的矿化速率提高，产生了大量 CO₂ 气体，这些气体与土壤中的水分发生化学反应形成碳酸溶液，溶解了一部分碳酸钙后生成重碳酸钙，随着土壤水分的蒸发，重碳酸钙又沉淀成为碳酸钙[10]。……