Abstract C input to soil together with plant-microbial-soil organic matter (SOM) transformations are key ecological drivers for soil functioning in perennial cropping systems. In this study, we assessed the effect of three woody (poplar, black locust, willow) and three herbaceous (giant reed, miscanthus, switchgrass) perennial energy crops (PECs) on SOM pools, soil microbial biomass and metabolism and soil P forms distribution. After 9 y from plantation on a low-grade arable land, PECs significantly increased SOM content as much as 3.9 g kg−1 (+23 %) in the topsoil (0−30 cm). At the same time active C increased by 194 mg kg−1 (+ 43 %) and microbial biomass by 10.7 mg g−1 (+ 80 %). Microbial catabolic activity as measured respectively with twenty enzymes activities (EA) involved in C-, N-, P-, and S- cycling increased by 90 % and C substrate utilization profile (CSU - Microresp™) showed an increase of respiration rate by 13 % on average of all 16 substrates utilized. PERMANOVA and dbRDA analysis indicated that activity of microbial community associated with PECs differed significantly from that of arable land, with herbaceous PECs significantly increasing EA involved in C and N cycling while woody PECs increasing those involved in P-cycling. Interestingly, organic P forms content (monoester- and diester-P) along with its contribution to total NaOH-EDTA extractable soil P increased in all PECs, but more in woody than herbaceous ones. Functional diversity and evenness of microbial community resulted higher under herbaceous than woody PECs. Depth decay relationships of Bray Curtis similarity for EA patterns, more than CSU profile, was significantly smaller in woody and arable land than in herbaceous PECs, indicating a significant control of plant C inputs to soil from deep-rooting systems on proximate agents of belowground functioning. Our investigation highlighted the higher capability PECs, compared to annual cropping systems, in coupling nutrients cycling with C cycling, with the high C input being most probably the driving factor. Therefore, PECs might be ultimately considered not just as energy crops but also as a valuable strategy for revitalizing depleted soils by conventional agricultural practices.

中文翻译：

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多年生能源作物的高碳输入可促进地下功能并增加土壤有机磷含量

摘要 土壤碳输入以及植物-微生物-土壤有机质 (SOM) 转化是多年生作物系统土壤功能的关键生态驱动力。在本研究中，我们评估了三种木本植物（杨树、刺槐、柳树）和三种草本植物（巨型芦苇、芒草、柳枝稷）多年生能源作物 (PECs) 对 SOM 库、土壤微生物生物量和代谢以及土壤 P 形态分布的影响. 在低等级耕地种植 9 年后，PEC 显着增加了表土（0-30 厘米）中 SOM 含量高达 3.9 g kg-1 (+23 %)。同时，活性碳增加了 194 mg kg-1 (+ 43 %)，微生物生物量增加了 10.7 mg g-1 (+ 80 %)。分别用参与 C-、N-、P-、和 S-循环增加了 90%，C 底物利用率曲线 (CSU-Microresp™) 显示所有 16 种底物的呼吸速率平均增加了 13%。PERMANOVA 和 dbRDA 分析表明，与 PEC 相关的微生物群落活动与耕地显着不同，草本 PEC 显着增加了参与 C 和 N 循环的 EA，而木质 PEC 增加了参与 P 循环的 EA。有趣的是，所有 PEC 中有机 P 形式的含量（单酯和二酯 P）及其对总 NaOH-EDTA 可提取土壤 P 的贡献增加，但在木本植物中比草本植物更多。草本 PEC 下微生物群落的功能多样性和均匀度高于木本 PEC。EA 模式的布雷柯蒂斯相似度的深度衰减关系，超过 CSU 剖面，木本和耕地中的 PEC 显着小于草本 PEC，表明植物 C 从深根系统对土壤的输入对地下功能的近因有显着控制。我们的调查强调，与一年生作物系统相比，PEC 在养分循环与 C 循环耦合方面具有更高的能力，高 C 输入很可能是驱动因素。因此，PECs 最终可能不仅被视为能源作物，而且还被视为通过传统农业实践振兴贫瘠土壤的宝贵战略。与一年生作物系统相比，在养分循环与碳循环耦合方面，高碳输入很可能是驱动因素。因此，PECs 最终可能不仅被视为能源作物，而且还被视为通过传统农业实践振兴贫瘠土壤的宝贵战略。与一年生作物系统相比，在养分循环与碳循环耦合方面，高碳输入很可能是驱动因素。因此，PECs 最终可能不仅被视为能源作物，而且还被视为通过传统农业实践振兴贫瘠土壤的宝贵战略。