Abstract

Natural reforestation on abandoned arable lands is one of the characteristic processes that trigger the transformation of soil organic matter accompanied by changes in the abundance, biomass, and taxonomic structure of soil macrofauna. The assessment of the time for a potential return of soil properties and macrofauna to their natural state, dynamics of soil organic matter stocks, and the role of macrofauna in this process at different stages of postagrogenic successions is relevant in the context of predicting the changes in ecosystem components and their role in organic carbon sequestration under various land use scenarios. The stock of organic carbon, soil morphological properties, as well as the abundance, biomass, and taxonomic structure of soil macrofauna in arable lands of five stages of pine forest restoration (fallow meadows and pine forests of different ages), and primary forests in the Smolenskoye Poozerye (Smolensk Lakeland) National Park (Smolensk oblast, Russia) have been examined. The soils of 85–100-year-old pine forests retain the lower boundary of the former humus horizon; at the meadow stage, restoration signs appear, namely, a shallow humus horizon pierced with roots and later transformed into a raw-humus horizon in young forests. By the age of 80, the carbon stock in the mineral soil part restores to almost background values. The soil macrofauna composition radically changes with the substitution of meadow communities by forest ones. At the initial stages (in agrocenoses and fallow meadows), the macrofauna of organomineral soil horizons is prevalent, being represented by soil earthworms and larvae of scarab beetles. Further, the macrofauna of organic horizons is restored to contain a high share of saprophages, such as epigeic and epi-endogeic earthworms, which contribute to the differentiation of litter into subhorizons. The biomass of saprophages negatively correlates with the carbon stock in the mineral part of forest soils, its content in the litter, and litter thickness and positively correlates with the share of easily decomposable litter fraction.

中文翻译：

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斯摩棱斯克州西北部生长后沙质土壤中的大型动物和有机质（俄罗斯）

摘要

废弃耕地的自然再造林是触发土壤有机质转化的特征过程之一，伴随着大型土壤动物的丰度、生物量和分类结构的变化。评估土壤性质和大型动物恢复自然状态的潜在时间、土壤有机质库的动态以及大型动物在生后演替不同阶段在此过程中的作用，对于预测土壤有机质变化具有重要意义。生态系统组成部分及其在各种土地利用情景下的有机碳固存中的作用。有机碳储量、土壤形态特征以及丰度、生物量、对松林恢复五个阶段（休耕草地和不同年龄的松林）的耕地以及斯摩棱斯克湖区国家公园（俄罗斯斯摩棱斯克州）原始森林的大型土壤动物和分类结构进行了检查。85-100年树龄的松林土壤保留了以前腐殖质层的下边界；在草甸阶段，出现了恢复迹象，即浅腐殖质地平线被根刺穿，随后在幼林中转变为原始腐殖质地平线。到80岁时，矿质土壤部分的碳储量几乎恢复到背景值。随着草地群落被森林群落取代，土壤大型动物群落的组成发生了根本性的变化。在初始阶段（在农田和休耕草地），有机矿物土壤层的大型动物很普遍，以土壤蚯蚓和圣甲虫幼虫为代表。此外，有机层的大型动物群得到恢复，含有大量腐食体，例如表生和表内生蚯蚓，这有助于将凋落物分化为地下层。腐食体的生物量与森林土壤矿物部分的碳储量、凋落物中的含量和凋落物厚度呈负相关，与易分解的凋落物部分的份额呈正相关。