Milda Pucetaite, Per Persson, Julia Parker, Ulf Johansson, Edith C. Hammer
{"title":"Visualization of soil aggregate structures provides insights into their formation mechanisms induced by litter inputs","authors":"Milda Pucetaite, Per Persson, Julia Parker, Ulf Johansson, Edith C. Hammer","doi":"10.1016/j.soilbio.2024.109686","DOIUrl":null,"url":null,"abstract":"Soil aggregation is a dynamic process influenced by physical, chemical and biological factors; however, their individual and combined effect on the formation and turnover of aggregates is not well understood. The aim of this study was to examine incorporation of fresh litter inputs of different physicochemical properties including their carbon-to-nitrogen (C/N) ratio – maize (C/N = 12) and straw (C/N = 103) - into aggregates, <em>de novo</em> formed from mineral soil with or without the presence of microbiota. Using rare-earth element oxides, we labelled structures formed during a four-week incubation with a single litter type and traced their incorporation into newly formed aggregates after mixing them together and incubating for a subsequent seven-week period. To visualize them, we used synchrotron-based X-ray fluorescence microspectroscopy, which allowed us to demonstrate that presence of the plant-derived particulate organic matter was the key factor for the aggregate formation. Within the timescale of the experiment, neither microbial abundance nor the community composition had any significant effect. However, the relative increase in straw-associated soil in aggregates larger than 250 μm provided support for our hypothesis regarding impact of carbon-rich organic matter on macroaggregation, likely via promotion of fungal growth and hyphal enmeshing. Phospholipid fatty acid analysis further confirmed relatively higher abundance of fungi in macroaggregates in straw-containing soil. All in all, our study provides insights into the initial stages of aggregate formation following litter additions and development of associated microbial community. The spatial analysis enabled by the X-ray fluorescence microspectroscopy enabled visualization of internal aggregate structures, shedding light on the processes involved, which is not possible with bulk analysis alone.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"1 1","pages":""},"PeriodicalIF":9.8000,"publicationDate":"2024-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Soil Biology & Biochemistry","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1016/j.soilbio.2024.109686","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"SOIL SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Soil aggregation is a dynamic process influenced by physical, chemical and biological factors; however, their individual and combined effect on the formation and turnover of aggregates is not well understood. The aim of this study was to examine incorporation of fresh litter inputs of different physicochemical properties including their carbon-to-nitrogen (C/N) ratio – maize (C/N = 12) and straw (C/N = 103) - into aggregates, de novo formed from mineral soil with or without the presence of microbiota. Using rare-earth element oxides, we labelled structures formed during a four-week incubation with a single litter type and traced their incorporation into newly formed aggregates after mixing them together and incubating for a subsequent seven-week period. To visualize them, we used synchrotron-based X-ray fluorescence microspectroscopy, which allowed us to demonstrate that presence of the plant-derived particulate organic matter was the key factor for the aggregate formation. Within the timescale of the experiment, neither microbial abundance nor the community composition had any significant effect. However, the relative increase in straw-associated soil in aggregates larger than 250 μm provided support for our hypothesis regarding impact of carbon-rich organic matter on macroaggregation, likely via promotion of fungal growth and hyphal enmeshing. Phospholipid fatty acid analysis further confirmed relatively higher abundance of fungi in macroaggregates in straw-containing soil. All in all, our study provides insights into the initial stages of aggregate formation following litter additions and development of associated microbial community. The spatial analysis enabled by the X-ray fluorescence microspectroscopy enabled visualization of internal aggregate structures, shedding light on the processes involved, which is not possible with bulk analysis alone.
期刊介绍:
Soil Biology & Biochemistry publishes original research articles of international significance focusing on biological processes in soil and their applications to soil and environmental quality. Major topics include the ecology and biochemical processes of soil organisms, their effects on the environment, and interactions with plants. The journal also welcomes state-of-the-art reviews and discussions on contemporary research in soil biology and biochemistry.