Qian Xu , Zhiyuan Yao , Yupei Chen , Na Liu , Zhuoran Teng , Donglin Huang , Weidong Cao , Yakov Kuzyakov , Tahir Shah , Na Zhao , Zhaohui Wang , Dabin Zhang , Yajun Gao
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引用次数: 0
Abstract
The input of organic C strongly alters the magnitude and direction of the microbial mineralization of soil organic matter (SOM), a phenomenon known as the “priming effect” (PE). The C:N ratios of additives are expected to affect the intensity of PE as it balances the C and N requirements of microbial growth. Growing of green manure (GM) crops in agricultural system strongly regulates PE intensity as it enhances the level and stability of SOM. However, the driving factors of additive C:N ratios and long-term GM crops on PE remain unclear. We addressed this knowledge gap by performing a 92-day incubation of 10-year summer fallow-wheat and GM-wheat soils by adding mixtures of 13C-labelled glucose and ammonium sulfate differing in the C:N ratio (15 vs. 50). The PE was increased by 148–288 % due to the high C:N ratio of the added mixtures, indicating that the quality of input exerted effects on the PE across the two soils. The PE of green manured (GMd) soil was increased by 23 % (p < 0.05) compared with that of summer fallow soil, as microorganisms produce extracellular enzymes such as β-glucosidase and leucine aminopeptidase to co-metabolize SOM. Nevertheless, compared with the summer fallow soil, 26 % more glucose-C was sequestered in GMd soil to compensate for C loss. We propose a conceptual model of “N mining” and “co-metabolism” to explain the effect of additive C:N ratio on PE in the soils under different GM practices. The “N mining” is the main cause of PE when the additive C:N ratio is high, and the “co-metabolism” becomes the dominant factor in long-term GMd soil with high SOM content and stability. Our findings demonstrate the importance of long-term incorporation of GM-driven changes in organic C inputs and SOM content and stability in regulating PE and soil C dynamics. Understanding the C dynamics under long-term GM practices contributes to formulate optimized agricultural strategies for promoting C sequestration and accurately predict soil C dynamics in the future.
有机碳的输入会强烈改变土壤有机质(SOM)微生物矿化的程度和方向,这种现象被称为 "引物效应"(PE)。添加剂的 C:N 比率预计会影响 PE 的强度,因为它会平衡微生物生长对 C 和 N 的需求。在农业系统中种植绿肥(GM)作物可提高 SOM 的水平和稳定性,从而对 PE 强度产生强有力的调节作用。然而,碳氮比添加和长期种植转基因作物对 PE 影响的驱动因素仍不清楚。为了填补这一知识空白,我们在 10 年夏季休耕-小麦土壤和转基因-小麦土壤中添加了 13C 标记的葡萄糖和硫酸铵混合物,并进行了为期 92 天的培养。由于添加的混合物的 C:N 比值较高,PE 增加了 148-288%,这表明投入物的质量对两种土壤的 PE 都有影响。与夏季休耕土壤相比,绿肥(GMd)土壤的 PE 增加了 23 %(p < 0.05),这是因为微生物产生了β-葡萄糖苷酶和亮氨酸氨肽酶等细胞外酶来共同代谢 SOM。尽管如此,与夏季休耕土壤相比,GMd 土壤中多固存了 26% 的葡萄糖-C,以补偿 C 的损失。我们提出了一个 "氮开采 "和 "共代谢 "的概念模型,以解释不同转基因实践下土壤中添加剂 C:N 比率对 PE 的影响。当添加剂 C:N 比值较高时,"N 开采 "是造成 PE 的主要原因,而在 SOM 含量和稳定性较高的长期转基因土壤中,"协同代谢 "则成为主要因素。我们的研究结果表明,长期转基因驱动的有机碳输入、SOM 含量和稳定性的变化对调节 PE 和土壤碳动态非常重要。了解长期转基因实践下的碳动态有助于制定促进碳固存的优化农业战略,并准确预测未来的土壤碳动态。
期刊介绍:
Applied Soil Ecology addresses the role of soil organisms and their interactions in relation to: sustainability and productivity, nutrient cycling and other soil processes, the maintenance of soil functions, the impact of human activities on soil ecosystems and bio(techno)logical control of soil-inhabiting pests, diseases and weeds.