Agronomic amendments drive a diversity of real and apparent priming responses within a grassland soil
Agronomic amendments drive a diversity of real and apparent priming responses within a grassland soil
复制标题
DOI：
10.1016/j.soilbio.2023.109265
复制
发表时间：
2024-02
影响因子：
9.7
通讯作者：
Robert W. Brown;Eleanor Y. Reed;David R. Chadwick;P. Hill;Davey L. Jones
中科院分区：
文献类型：
--
作者：
Robert W. Brown;Eleanor Y. Reed;David R. Chadwick;P. Hill;Davey L. Jones
土壤碳（C）固存通常被视为有助于缓解气候变化的基于自然的解决方案。实现这一潜力的关键是更好地了解哪些碳投入促进了更大的长期碳储存。引发效应（PE）是由于向土壤中添加有机或矿物改良剂而引起的微生物土壤有机质（SOM）分解速率的变化。基质的表观PE（微生物生物量周转产生的CO2变化）经常被作为一个混杂因素进行研究，然而，由于C库分化的不确定性，真实的PE（天然SOM的分解）很少被测量。在这里，我们使用了50天的围隔生态系统的研究，比较各种常见的土壤改良剂（木材生物炭和灰分，蛋白质，氨基酸，葡萄糖，纤维素，牛粪（FYM），牛泥浆，无机N肥，和不同比例的小麦秸秆：芽混合物）对土壤的真实的和表观PE的影响，使用5岁的准稳定14 C标记的SOM和14 C标记的活性微生物生物量，分别。我们的研究结果表明，经常有显着的差异，在真实的和表观PE，为相同的修正案，方差的大小，在某些情况下，方向。我们在两个试验中确定了几个一致的PE驱动因素，然而，处理的初始C：N比与PE之间存在负相关关系，这表明虽然C修正物的营养化学计量很重要，但微生物群落底物的可用性和质量是决定其引发反应的关键。同样，背景对于解释也很重要，因为引起正启动的处理可能仍然在补充或增加土壤碳储量。
Soil carbon (C) sequestration is often viewed as a nature-based solution to help mitigate climate change. Key to realising this potential is a better understanding of which C inputs promote greater long-term C storage. The priming effect (PE) is the change in rates of microbial soil organic matter (SOM) decomposition caused by the addition of organic or mineral amendments to soil. The apparent PE (changes in CO2from microbial biomass turnover) of substrates is often studied as a confounding factor, however, the real PE (decomposition of native SOM) is rarely measured due to uncertainties in C pool differentiation. Here, we used a 50-day mesocosm study to compare the effect of various common soil amendments (wood biochar and ash, protein, amino acids, glucose, cellulose, cattle farmyard manure (FYM), cattle slurry, inorganic N fertiliser, and different ratios of wheat straw:shoot mixes) on the real and apparent PEs of soil, using 5-year old quasi-stable14C-labelled SOM and14C-labelled active microbial biomass, respectively. Our results show that there are often significant differences in the real and apparent PE, for the same amendment, with variance in magnitude and, in some case, direction. We identified few consistent drivers of PE across the two assays, however, there was a negative relationship between the initial C:N ratio of the treatment and PEs, suggesting that while the nutrient stoichiometry of the C amendment is important, the usability and quality of the substrate for the microbial community are key to determining its priming response. Equally, context is important for interpretation, as treatments that elicit positive priming may still be replenishing or increasing soil C stocks.