Polyakov Vyacheslav, Abakumov Evgeny, Lodygin Evgeny, Vasilevich Roman, Petrov Alexey
Department of Applied Ecology, Faculty of Biology, St. Petersburg State University, 7/9 Universitetskaya emb., 199034 St. Petersburg, Russia.
Arctic and Antarctic Research Institute, Beringa 38, 199397 St. Petersburg, Russia.
Molecules. 2024 Jun 25;29(13):3008. doi: 10.3390/molecules29133008.
The transition of soils into fallow state has a significant impact on the accumulation and transformation of soil organic matter (SOM). However, the issue of SOM transformation as a result of soil transition to fallow state in cryolithozone conditions is insufficiently studied. The aim of this study is to investigate the molecular weight (MW) distribution of humic acids (HAs) isolated from soils of central Yakutia. Native, fallow and agricultural soils in the vicinity of Yakutsk city were studied. MW distributions of HA preparations were obtained on an AKTAbasic 10 UPS chromatographic system (Amersam Biosciences, Uppsala, Sweden) using a SuperdexTM 200 10/300 GL column (with cross-linked dextran gel, fractionation range for globular proteins 10-600 kDa). The data on the molecular-mass distribution of HAs of fallow and agricultural soils of Central Yakutia were obtained for the first time. According to the obtained data, it was found that the highest carbon content in the structure of HAs was observed in agricultural soils (52.56%), and is associated with soil cultivation and fertilizer application. Among the HAs of fallow soils, we note that those soils that are in the process of self-vegetation have a relatively high carbon content in the HAs (45.84%), but the highest content was observed in fallow soils used as hayfields (49.98%), indicating that the reinvolvement of agriculture in fallow soils leads to an increase in the carbon content of HAs. According to the data of the MW distribution of HAs, it was found that the highest content of a high MW fraction of HAs was recorded in native soil (18.8%); this is due to the early stages of humification and the low maturity of organic matter. The highest content of a low MW fraction of HAs was recorded in agricultural soil (73.3%); this is due to the formation of molecular complexes of a "secondary" nature, which are more stable in the environment than the primary transformation products of humification precursors. The molecular composition of the HAs of fallow soils in the process of self-overgrowing is characterized by values closer to the HAs of native soils, which indicates their transformation towards HAs of native soils. The obtained results indicate that the reinvolvement of fallow soils leads to the transformation of the molecular composition of HAs towards HAs of agricultural soils, and to an increase in the resistance of SOM to biodegradation.
土壤向休闲状态的转变对土壤有机质（SOM）的积累和转化有重大影响。然而，在冻土带条件下，土壤转变为休闲状态导致的SOM转化问题研究不足。本研究的目的是调查从雅库特中部土壤中分离出的腐殖酸（HA）的分子量（MW）分布。对雅库茨克市附近的原生、休闲和农业土壤进行了研究。使用SuperdexTM 200 10/300 GL柱（交联葡聚糖凝胶，球状蛋白质的分级范围为10 - 600 kDa）在AKTAbasic 10 UPS色谱系统（瑞典乌普萨拉的Amersam Biosciences公司）上获得HA制剂的MW分布。首次获得了雅库特中部休闲和农业土壤中HA分子量分布的数据。根据所得数据发现，农业土壤中HA结构中的碳含量最高（52.56%），这与土壤耕作和施肥有关。在休闲土壤的HA中，我们注意到处于自然植被恢复过程中的那些土壤，其HA中的碳含量相对较高（45.84%），但用作干草地的休闲土壤中碳含量最高（49.98%），这表明农业重新参与休闲土壤会导致HA中碳含量增加。根据HA的MW分布数据发现，原生土壤中HA高分子量部分的含量最高（18.8%）；这是由于腐殖化早期阶段和有机质成熟度低所致。农业土壤中HA低分子量部分的含量最高（73.3%）；这是由于形成了“次生”性质的分子复合物，它们在环境中比腐殖化前体的初级转化产物更稳定。自然植被恢复过程中休闲土壤HA的分子组成特征值更接近原生土壤的HA，这表明它们向原生土壤的HA转化。所得结果表明，休闲土壤的重新利用导致HA的分子组成向农业土壤的HA转化，并导致SOM对生物降解的抗性增加。
