Initial utilization of rhizodeposits with rice growth in paddy soils: Rhizosphere and N fertilization effects
Initial utilization of rhizodeposits with rice growth in paddy soils: Rhizosphere and N fertilization effects
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水稻土中水稻生长根际沉积物的初步利用：根际和氮肥效应
DOI：
10.1016/j.geoderma.2018.11.040
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发表时间：
2019
期刊：
影响因子：
6.1
通讯作者：
Wu Jinshui
中科院分区：
文献类型：
--
作者：
Liu Yalong;Ge Tida;Ye Jun;Liu Shoulong;Shibistova Olga;Wang Ping;Wang Jingkuan;Li Yong;Guggenberger Georg;Kuzyakov Yakov;Wu Jinshui
腐殖酸沉积是土壤微生物可利用的碳源和能量来源，在生态系统碳和养分循环的调节中起着重要作用，对碳的固存产生重要影响。水稻根碳在土壤中的动态及其在水稻生长过程中对微生物的分配，以及氮肥（N-NH 4+）施肥的影响知之甚少，特别是在微生物对根碳的初始吸收及其在整个生长期的利用方面。为了评估这两个过程，水稻植株在有或没有施氮肥（0和225 kg N-NH 4 +ha−1）的盆中生长，并在13 CO2脉冲标记后6小时内通过磷脂脂肪酸（PLFA）分析追踪13 C掺入微生物组。标记进行了5个生长阶段：分蘖，伸长，抽穗，灌浆，成熟。13 C纳入土壤微生物生物量C变化迅速，在开始的研究期间，伸长之前，但此后保持稳定。13 C纳入根际和散装土壤微生物生物量高于无N添加。这种刺激可能是由于过量增加植物体形成和根系分泌物后，施氮和增加同化碳输入到土壤中。结构方程模型表明，施氮强烈影响根际和非根际碳转移。因此，N-NH 4+的应用不仅可以增加根碳流入微生物，但它也可能增加根际对散装土壤微生物和随后的过程中有关的土壤碳循环的影响。
Rhizodeposition represents a readily available C and energy source for soil microorganisms, that plays an important role in the regulation of C and nutrient cycling in ecosystems and exerts a strong influence on C sequestration. The dynamics of rice rhizo-C in soils and its allocation to microorganisms during rice growth, as well as the effects of nitrogen (N-NH4+) fertilization are poorly understood, particularly with respect to the initial uptake of rhizo-C by microorganisms and its utilization during the entire growth period. To assess these two processes, rice plants were grown in pots with or without N fertilization (0 and 225 kg N-NH4+ha−1), and13C incorporation into microbial groups was traced by phospholipid fatty acids (PLFAs) analysis within 6 h after13CO2pulse labeling. Labeling was performed at five growth stages: tillering, elongation, heading, filling, and maturation.13C incorporated into soil microbial biomass C changed rapidly at the beginning of the study period, before elongation, but remained stable thereafter.13C incorporation into rhizosphere and bulk soil microbial biomass was higher with than without N addition. This stimulation was likely due to the excessive increase in phytomass formation and root exudates after N fertilization and the increased assimilate C input into the soil. Structural equation modelling suggested that N fertilization strongly affected carbon transfer between rhizosphere and non-rhizosphere. Hence, N-NH4+application may not only increase rhizo-C flow into microorganisms but it may also increase the effect of rhizosphere on bulk-soil microorganisms and subsequent processes related to soil C-cycling.