Sources and mechanisms of priming effect induced in two grassland soils amended with slurry and sugar
Sources and mechanisms of priming effect induced in two grassland soils amended with slurry and sugar
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DOI：
10.1016/j.soilbio.2005.06.025
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发表时间：
2006-04-01
影响因子：
9.7
通讯作者：
Bol, R
中科院分区：
文献类型：
--
作者：
Kuzyakov, Y;Bol, R
引发效应的机制和具体来源，即添加物质后土壤有机质分解的短期变化，目前仍不完全清楚。这些不确定性部分与方法有关，即到目前为止，只能确定释放的CO2中的两个C源。我们使用了一种新的方法来分离土壤中CO2排放中的三种碳（C）源。该方法基于在不同处理中源自C-3或C-4植物的不同物质的组合以及物质如C-3糖（来自甜菜）和C-4糖（来自甘蔗）的相同转化。我们研究了添加两种物质具有不同的微生物利用率，即浆料和糖的SOM或/和浆料分解在两个草原土壤中具有不同水平的C-org（2.3与5.1%C）的影响。施用泥浆对土壤有机质的分解有一定的促进作用。添加糖导致的变化的SOM和浆料分解清楚地表征为两个阶段：糖添加后，立即微生物切换从难以利用的SOM的分解容易利用的糖的分解。这个第一阶段非常短（2-3天），因此在其他实验中经常错过。第二阶段表现出轻微增加的泥浆和SOM分解（与无糖土壤相比）。通过对草地土壤CO2排放的3个来源的分析，得出了草地土壤中C的利用程度为：蔗糖>沼液>有机质的结论。此外，分解更惰性的C（这里SOM）在密集的糖分解期间强烈减少（负启动效应）。我们的结论是，启动效应涉及一系列的机制：（i）优先底物利用，（ii）活化的微生物生物量容易利用基板（iii）随后增加利用以下基板根据其利用率，（iv）下降到初始状态。(c)2005爱思唯尔有限公司保留所有权利。
The mechanisms and specific sources of priming effects, i.e. short term changes of soil organic matter (SOM) decomposition after substance addition, are still not fully understood. These uncertainties are partly method related, i.e. until now only two C sources in released CO2 could be identified. We used a novel approach separating three carbon (C) sources in CO2 efflux from soil. The approach is based on combination of different substances originated from C-3 or C-4 plants in different treatments and identical transformation of substances like C-3 sugar (from sugar beet) and C-4 sugar (from sugar cane). We investigated the influence of the addition of two substances having different microbial utilizability, i.e. slurry and sugar on the SOM or/and slurry decomposition in two grassland soils with different levels of C-org (2.3 vs. 5.1% C). Application of slurry to the soil slightly accelerated the SOM decomposition. Addition of sugar lead to changes of SOM and slurry decomposition clearly characterized by two phases: immediately after sugar addition, the microorganisms switched from the decomposition of hardly utilizable SOM to the decomposition of easily utilizable sugar. This first phase was very short (2-3 days), hence was frequently missed in other experiments. The second phase showed a slightly increased slurry and SOM decomposition (compared to the soil without sugar). The separation of three sources in CO2 efflux from grassland soils allowed us to conclude that the C will be utilized according to its utilizability: sugar > slurry > SOM. Additionally, decomposition of more inert C (here SOM) during the period of intensive sugar decomposition was strongly reduced (negative priming effect). We conclude that, priming effects involve a chain of mechanisms: (i) preferential substrate utilization, (ii) activation of microbial biomass by easily utilizable substrate (iii) subsequent increased utilization of following substrates according to their utilizability, and (iv) decline to initial state. (c) 2005 Elsevier Ltd. All rights reserved.