In Eastern Spain, almond trees have been cultivated in terraced orchards for centuries, forming an integral part of the Mediterranean forest scene. In the last decades, orchards have been abandoned due to changes in society. This study investigates effects of changes in land use from forest to agricultural land and the posterior land abandonment on soil microbial community, and the influence of soil physico-chemical properties on the microbial community composition (assessed as abundances of phospholipids fatty acids, PLFA). For this purpose, three land uses (forest, agricultural and abandoned agricultural) at four locations in SE Spain were selected. Multivariate analysis showed a substantial level of differentiation in microbial community structure according to land use. The microbial communities of forest soils were highly associated with soil organic matter content. However, we have not found any physical or chemical soil property capable of explaining the differences between agricultural and abandoned agricultural soils. Thus, it was suggested that the cessation of the perturbation caused by agriculture and shifts in vegetation may have led to changes in the microbial community structure. PLFAs indicative of fungi and ratio of fungal to bacterial PLFAs were higher in abandoned agricultural soils, whereas the relative abundance of bacteria was higher in agricultural soils. Actinomycetes were generally lower in abandoned agricultural soils, while the proportions of vesicular-arbuscular mycorrhyzal fungi were, as a general trend, higher in agricultural and abandoned agricultural soils than in forests. Total microbial biomass and richness increased as agricultural < abandoned agricultural < forest soils.

中文翻译：

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西班牙东部山区农业梯田废弃后土壤微生物群落结构的变化

在西班牙东部，几个世纪以来，杏仁树一直在梯田中种植，形成了地中海森林景观中不可或缺的一部分。在过去的几十年里，由于社会的变化，果园被废弃了。本研究调查了从森林到农业用地的土地利用变化和后遗弃地对土壤微生物群落的影响，以及土壤理化性质对微生物群落组成的影响（评估为磷脂脂肪酸的丰度，PLFA）。为此，在西班牙东南部的四个地点选择了三种土地用途（森林、农业和废弃农业）。多变量分析表明，根据土地利用，微生物群落结构存在显着差异。森林土壤微生物群落与土壤有机质含量高度相关。然而，我们还没有发现任何能够解释农业土壤和废弃农业土壤之间差异的物理或化学土壤特性。因此，有人认为农业引起的扰动停止和植被变化可能导致微生物群落结构发生变化。废弃农业土壤中指示真菌的 PLFAs 和真菌与细菌 PLFAs 的比率较高，而农业土壤中细菌的相对丰度较高。放线菌在废弃农田土壤中普遍较低，而水泡-丛枝菌根真菌在农田和废弃农田土壤中的比例总体上高于森林。