Long-term continuouscroppingcan lead to the deterioration of soil environment and the decrease of soil productivity. However, the biological mechanism on the negative effects of long-term continuous cropping has not been extensively explored. Soil nematode food web with multiple trophic levels play critical roles in nutrient cycling and energy flowing in the agroecosystem. Quantifying the carbon flux through different trophic channels within the nematode food web can indicate how continuous cropping influences carbon cycling in the agroecosystem by altering soil biota communities. Therefore, the effects of continuous peanut cropping with different years (1, 5, 20, and 30 years) on soil properties, soil nematode community composition, carbon flux within nematode food web and crop yields were investigated. Results showed that soil pH significantly decreased with increasing continuous cropping years. Differently, soil organic carbon and total nitrogen were the highest in 20-year, and decreased in 30-year of continuous cropping. As continuous cropping years increased, the relative abundance of microbivorous nematodes decreased and that of plant parasites reached as high as 76.11 % and 68.22 % in 20- and 30-year, respectively. Pearson correlation analysis revealed the nematode diversity, the carbon flux uniformity and peanut yield had a significant negative correlation with continuous cropping years. The random forest model indicated that the soil pH and the relative abundance of plant parasites were the key influence factor of the carbon flux uniformity within soil nematode food web. Outbreaks of plant parasites lead to the disruption of carbon flux uniformity within soil nematode food web, which can increase the risk of peanut yield decline after long-term continuous cropping. In conclusion, continuous peanut cropping changed soil properties, reduced soil nematode diversity, and disturbed the multitrophic carbon flux complementarity and uniformity in soil nematode food web, ultimately limiting the crop productivity. This study enhances our understanding of the importance of the resource transfers among soil food web in maintaining sustainable agroecosystem productivity.

中文翻译：

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连作障碍：来自土壤线虫食物网内群落组成和碳通量不平衡的见解


长期连作会导致土壤环境恶化，土壤生产力下降。然而，长期连作负面影响的生物学机制尚未得到广泛探索。具有多个营养级的土壤线虫食物网在农业生态系统中的养分循环和能量流动中起着关键作用。量化线虫食物网中不同营养通道的碳通量可以表明连作如何通过改变土壤生物群落来影响农业生态系统中的碳循环。因此，研究了不同年份（1、5、20 和 30 年）连作花生对土壤性质、土壤线虫群落组成、线虫食物网内碳通量和作物产量的影响。结果表明，随着连作年限的增加，土壤 pH 值显著降低。土壤有机碳和全氮在 20 a中最高，在 30 a连作中下降。随着连作年限的增加，微生物食性线虫的相对丰度下降，植物寄生虫的相对丰度在 20 年和 30 年分别高达 76.11% 和 68.22 %。Pearson 相关分析显示，线虫多样性、碳通量均匀性和花生产量与连作年限呈显著负相关。随机森林模型表明，土壤 pH 值和植物寄生虫的相对丰度是土壤线虫食物网内碳通量均匀性的关键影响因素。 植物寄生虫的爆发导致土壤线虫食物网内碳通量均匀性的破坏，这会增加花生长期连作后产量下降的风险。综上所述，连续种植花生改变了土壤性质，降低了土壤线虫多样性，扰乱了土壤线虫食物网中的多营养碳通量互补性和均匀性，最终限制了作物的生产力。这项研究增强了我们对土壤食物网之间资源转移在维持可持续农业生态系统生产力中的重要性的理解。