Plant species and plant neighbor identity affect associations between plant assimilated C inputs and soil pores
Plant species and plant neighbor identity affect associations between plant assimilated C inputs and soil pores
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DOI：
10.1016/j.geoderma.2021.115565
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发表时间：
2022-02
期刊：
影响因子：
6.1
通讯作者：
H. Zheng;A. Guber;Y. Kuzyakov;W. Zhang;A. Kravchenko
中科院分区：
文献类型：
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作者：
H. Zheng;A. Guber;Y. Kuzyakov;W. Zhang;A. Kravchenko
众所周知，更大的植物多样性有助于土壤碳的获得，但这种影响的确切机制仍在深入讨论中。一种植物是在单一栽培中生长还是在多物种混合中生长，都会影响植物同化物的分配、地下分泌物和微生物刺激。本研究的目的是研究间作对以前被忽视的植物-土壤相互作用的一个方面的影响，即对植物同化C在土壤孔隙系统中的分配位置以及随后与土壤孔隙分布有关的命运的影响。本研究的土壤来源于一种柳枝枝草(Panicum virgatumL.)(变种Caves‘n’Rock)(西南)、大蓝茎(Andrepogon GerardiiVitman)(BB)和野生佛手柑(Monarda fiumulosaL.)(WB)以单一栽培和间作对种植，并接受物种特有的13C脉冲标记(Kravchenko等人，2021年)。从实验盆栽中采集完整的土壤岩心(直径8 mm)，进行短期(10天)培养、X射线计算机微层析(µCT)扫描和土壤13C微采样。结果表明，在具有示范植物间C转移土壤的植物系统中，13C与植株终止后即刻的10微米厚的孔隙度和培养后的20~80微米厚的孔隙度呈正相关。在没有明显间作C转移土壤的系统中，~(13)C与20~30µm的孔隙度呈正相关，但在培养后这种相关性消失。在培养过程中，具有地下碳转移的系统的土壤表现出较低的根源碳损失，而植株间碳转移可以忽略不计的系统。促进植物间碳转移的因素似乎也导致根来源的C进入较小的气孔，并在那里得到更大的保护。
Greater plant diversity is known to facilitate soil C gains, yet the exact mechanisms of this effect are still under intensive discussion. Whether a plant grows in monoculture or in a multi-species mixture can affect allocation of plant assimilates, belowground exudation, and microbial stimulation. The goal of this study was to examine the effects of inter-cropping on a previously overlooked aspect of plant-soil interactions, namely, on locations where plant assimilated C is allocated within the soil pore system and its subsequent fate in relation to soil pore size distributions. The soil for the study originated from a greenhouse experiment with switchgrass (Panicum virgatumL.) (var. Cave'n'Rock) (SW), big bluestem (Andropogon gerardiiVitman) (BB), and wild bergamot (Monarda fistulosaL.) (WB) grown in monocultures and in inter-cropped pairs and subjected to species specific13C pulse labeling (Kravchenko et al., 2021). Intact soil cores (8 mm Ø) were collected from the experimental pots, subjected to a short-term (10 day) incubation, X-ray computed micro-tomography (µCT) scanning, and soil13C micro-sampling “geo-referenced” to µCT images. Results indicated that in the plant systems with demonstrated interplant C transfer soil13C was positively correlated with < 10 µm Ø pores immediately after plant termination and with 20–80 µm Ø pores after the incubation. In the systems without marked interplant C transfer soil,13C was positively correlated with 20–30 µm Ø pores, however, the correlations disappeared after the incubation. Soils from the systems with demonstrated belowground C transfer displayed lower losses of root-derived C during incubation than the systems where interplant C transfer was negligible. Factors facilitating interplant C transfer appear to also lead to placement of root-derived C into smaller pores and to its greater protection there.