Abstract

The results of a long-term study of changes in soils and vegetation during postagrogenic succession of sown meadows on reclaimed peat soils (Eutric Histosols) are presented. The study was performed on experimental plots in the Korzinskaya Lowland (Karelia); sowing of perennial grasses was accompanied by the application of mineral fertilizers. Observations over changes in the vegetation communities along with the reduction of the peat thickness were conducted. The soil samples were analyzed for the organic carbon, total nitrogen, and available phosphorus contents and for the pH of salt extracts. Vegetation was described using the Braun-Blanquet approach; the botanical composition and the biomass of herbs were assessed by their cutting and weighing. Nematode communities were characterized by their taxonomic diversity, population density, and eco-trophic structure. The analysis of soil profiles demonstrated that the thickness of the peat deposits decreased over 40 years of observation (1974–2015). The direction of vegetation succession on sown meadows was dictated by the type of fertilization. Two plant communities were formed: Deschampsieta caespitosae humidiherbosum developed on the plots treated with mineral fertilizers, and Elytrigeto magnograminosoherbosum community developed on the plots treated with mineral and organic fertilizers. The main changes in soil nematode communities during the long-term succession were related to their eco-trophic structure. Two trophic groups exhibited an obvious response: the relative abundance of nematodes associated with plants decreased, whereas the share of plant-parasitic nematodes increased. In addition, it was found that the species composition of herbs predetermined the ecological specialization of dominant plant-parasitic nematode taxa.

中文翻译：

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泥炭土壤和植被的农艺转化后土壤线虫群落的变化

摘要

提出了在再生的泥炭土（Eutric Histosols）上播种后的草地进行农耕后演替期间土壤和植被变化的长期研究结果。该研究是在Korzinskaya Lowland（卡累利阿）的实验地块上进行的；多年生禾草的播种伴随着矿物肥料的应用。观察了植被群落的变化以及泥炭厚度的减少。分析土壤样品中的有机碳，总氮，有效磷含量以及盐提取物的pH。使用Braun-Blanquet方法描述了植被；通过切割和称重来评估草药的植物成分和生物量。线虫群落的特征在于其分类学多样性，人口密度，和生态营养结构。对土壤剖面的分析表明，经过40年的观察（1974-2015年），泥炭沉积物的厚度减小了。施肥类型决定了播种草地上植被演替的方向。形成了两个植物群落：在用矿物肥料处理的地块上发展了Deschampsieta caespitosae湿地植物，而在用矿物肥料和有机肥料处理的地上发展了Elytrigeto magnograminosoherherum群落。长期演替过程中土壤线虫群落的主要变化与其生态营养结构有关。两个营养族表现出明显的响应：与植物相关的线虫的相对丰度降低，而植物寄生线虫的比例增加。此外，还发现草药的物种组成预先确定了优势植物寄生线虫类群的生态专业化。