Han Young-Soo, Tokunaga Tetsu K
Earth Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, USA; Korea Institutes of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon, Republic of Korea.
Earth Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, USA.
Chemosphere. 2014 Dec;117:87-93. doi: 10.1016/j.chemosphere.2014.05.084. Epub 2014 Jun 26.
Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.
大气中二氧化碳浓度不断增加以及随之而来的气候变化，引发了人们对土壤碳平衡管理的新兴趣。在此，我们在土壤柱中进行了实验，以确定添加和不添加硫酸钙矿物（硬石膏和石膏）时的碳质量平衡，假设这些矿物在微碱性条件下可促进土壤有机碳（SOC）的保留和方解石形式的土壤无机碳（SIC）沉淀。在经过一年测试的非饱和土壤柱中测量了三相（气相、液相和固相）中碳含量的变化，并确定了综合碳质量平衡。测试的土壤柱没有碳输入，在碳化学中仅假设微生物活动对碳的利用和碳转化。测量结果表明，碳储量的变化通过两个过程发生，即SOC损失和SIC增加。然而，处理过的土壤柱中测得的SOC损失低于相应的对照柱，这表明添加物促进了SOC的保留。SOC损失主要源于微生物呼吸作用和二氧化碳向大气中的损失，而非化学淋溶。硫酸钙矿物溶解产生的Ca(2+)和SO4(2)(-)增加似乎抑制了SOC的微生物氧化。在所测试的条件下，硫酸钙处理下每平方米土壤面积的SIC积累量在130至260克碳每立方米渗透水之间（净碳效益为20至120克碳每立方米渗透水）。这些结果证明了通过硫酸钙处理在微碱性土壤中增加碳固存的潜力。
