Laboratory of Conservation and Dynamics of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Avenida Francisco Salazar, P.O. Box 54-D, 01145, Temuco, Chile.
Network for Extreme Environmental Research (NEXER), Universidad de La Frontera, Temuco, Chile.
Sci Rep. 2021 Mar 19;11(1):6438. doi: 10.1038/s41598-021-84821-6.
When studying carbon (C) sequestration in soil, it is necessary to recognize the maximal storage potential and the main influencing factors, including the climate, land use, and soil properties. Here, we hypothesized that the silt and clay contents in soils as well as the clay mineralogy are the main factors affecting the maximal C and N storage levels of soils. This hypothesis was evaluated using a database containing the organic C contents of topsoils separated by ultrasonic dispersion to determine the particle size fractions. The slopes of the linear regressions between the C contents in silt and clay to the soil organic C (SOC) and between the N contents in silt and clay to the total N content were independent of the clay mineralogy (2:1, 1:1, calcareous soil, amorphous clays), climate type (tropical, temperate, and Mediterranean), and land use type (cropland, grassland, and forest). This clearly shows that the silt and clay content is the main factor defining an upper SOC level, which allowed us to propose a generalized linear regression (R > 0.95) model with a common slope, independent of the land use and climate type, to estimate the soil C sequestration potential. The implications of these findings are as follows: (1) a common slope regression was accurately calculated (0.83 ± 0.02 for C-silt + clay < 63 μm and 0.81 ± 0.02 for C-silt + clay < 20 μm) and (2) there was no asymptotic pattern found to support the existence of an SOC saturation pool.
在研究土壤中的碳（C）固存时，有必要认识到最大存储潜力和主要影响因素，包括气候、土地利用和土壤特性。在这里，我们假设土壤中的粉粒和粘粒含量以及粘土矿物学是影响土壤最大 C 和 N 存储水平的主要因素。这一假设是通过使用一个数据库来评估的，该数据库包含了通过超声波分散分离的表土中的有机 C 含量，以确定粒径分数。粉粒和粘粒中 C 含量与土壤有机 C（SOC）之间以及粉粒和粘粒中 N 含量与总 N 含量之间的线性回归斜率独立于粘土矿物学（2:1、1:1、钙质土壤、无定形粘土）、气候类型（热带、温带和地中海）和土地利用类型（耕地、草地和森林）。这清楚地表明，粉粒和粘粒含量是定义 SOC 上限的主要因素，这使我们能够提出一个具有共同斜率的广义线性回归（R>0.95）模型，该模型独立于土地利用和气候类型，用于估计土壤的碳固存潜力。这些发现的意义如下：（1）准确计算了共同斜率回归（0.83±0.02 用于 C-粉粒+粘粒<63 μm 和 0.81±0.02 用于 C-粉粒+粘粒<20 μm）；（2）没有发现渐近模式来支持 SOC 饱和池的存在。
