Soil micro-food webs play an important role in ecosystem functions through energy flow; they are strongly influenced by land use types. Previous studies have typically utilized the space-for-time substitution or single-time sampling method to reflect the land-use change effects by comparing differences among existing land-use types. These methods would increase random error. Research on how synchronized land-use change (starting at the same time and place) influences soil ecological processes and functions is urgently needed. Based on a controlled field experiment and seven years of observations, this study explored the effects of land-use change from natural shrubland to cropland (maize), forage land (tall-grass forage), and economic forest land (walnut plantation) on the community structure and energy dynamics of the soil micro-food webs. Cropland simplified the complexity of the soil food webs compared to the other three land-uses. Forage grassland maintained the highest biomasses of soil total microbes, fungi, and arbuscular mycorrhizal fungi. In addition, economic forest land improved the flow uniformity of the micro-food web by increasing energy transfer from resources to bacterivores, fungivores, and herbivores while decreasing herbivore energy flow to omnivores-predators. Omnivore abundance and nematode diversity were important predictors of total energy flux and flow uniformity of the soil micro-food webs, respectively. In addition, omnivores maintained the complexity of soil micro-food webs by promoting interactions among trophic groups through top-down control. Soil organisms are sensitive to the response of agricultural management and planting time, and it may take several years or more to reach a dynamic equilibrium. Different types and levels of ecosystem disturbance (e.g., tillage and no-tillage, fertilizer rates, aboveground biomass removal intensity) may be the major drivers of soil community during land use change. Our findings highlight the importance of conservation agriculture in maintaining soil food web structure and energy flow for future sustainable land uses, and that promoting omnivore abundance is essential for food web complexity and stability.

中文翻译：

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七年土地利用变化期间，干扰强度塑造土壤微食物网组成和能量通量

土壤微食物网通过能量流动在生态系统功能中发挥重要作用；它们受到土地利用类型的强烈影响。以往的研究通常采用空间换时间或单次抽样的方法，通过比较现有土地利用类型之间的差异来反映土地利用变化的影响。这些方法会增加随机误差。迫切需要研究同步土地利用变化（同时、同一地点开始）如何影响土壤生态过程和功能。本研究基于对照田间试验和七年的观测，探讨了土地利用从天然灌木林到耕地（玉米）、饲草地（高草饲草）和经济林地（核桃林）的变化对土地利用的影响。土壤微食物网的群落结构和能量动态。与其他三种土地利用相比，农田简化了土壤食物网的复杂性。饲草草地土壤总微生物、真菌和丛枝菌根真菌生物量最高。此外，经济林地通过增加从资源到食菌动物、食真菌动物和食草动物的能量转移，同时减少食草动物到杂食动物-捕食动物的能量流动，改善了微食物网的流动均匀性。杂食动物丰度和线虫多样性分别是土壤微食物网总能量通量和流动均匀性的重要预测因子。此外，杂食动物通过自上而下的控制促进营养群体之间的相互作用，从而维持了土壤微食物网的复杂性。土壤生物对农业管理和种植时间的反应很敏感，可能需要几年甚至更长的时间才能达到动态平衡。不同类型和水平的生态系统干扰（例如耕作和免耕、施肥量、地上生物量去除强度）可能是土地利用变化过程中土壤群落的主要驱动因素。我们的研究结果强调了保护性农业在维持土壤食物网结构和能量流动以实现未来可持续土地利用方面的重要性，并且促进杂食动物丰富度对于食物网的复杂性和稳定性至关重要。