The management and environmental factors controlling microbial biomass and community structure were identified in a three-year field experiment. here. After the easily available C was exhausted, soil properties regulated the microbial functional diversity, and the main parameters of soil properties were soil organic C and clay content. Total fiber content of organic material (cellulose, hemicellulose and lignin), total organic C, and total organic N were determined. 2018; 13(9):e0203812 (ISSN: 1932-6203) Basic soil parameters (e.g. Van Horn1, M. Lee Van Horn2, John E. Barrett3, Michael N. Gooseff4, Adam E. Altrichter3, Kevin M. Geyer3, Lydia … Ferralic Cambisol is found in the subtropical region with an acidic soil environment , Calcaric Cambisol is found in the warm temperate region with a weak basic or neutral soil environment, and Calcaric Cambiso is found in the cold temperate region with a weak acidic or neutral soil environment. https://doi.org/10.1371/journal.pone.0203812.s001, https://doi.org/10.1371/journal.pone.0203812.s002. To date, most studies of soil microbial characteristics with different organic materials amendment concentrated mainly on a certain soil or different soils under controlled laboratory conditions [17, 19]; little information is reported about comparative studies of microbial characteristics dynamics in soils developed from different parent materials after amendment with different organic materials under field conditions. Soil properties, such as parent material, soil organic matter, pH and clay content can also influence soil microbial biomass and functional diversity [19–21]. It has been showed that soil microbial diversity decreased with the increase of latitude and was positively correlated with air temperature , and Luvic Phaeozem in this study was developed from the highest latitude and the annual average temperature (4–5°C) in its local region was lower than the other two soils. Methodology, As a result, AWCD and McIntosh index were low in Calcaric Cambisol because of its high initial pH (Table 1) at the end of the 1st month. Different letters indicate significant differences at P < 0.05 among different materials in the same soil. https://doi.org/10.1371/journal.pone.0203812, Editor: Jingdong Mao, Old Dominion University, UNITED STATES, Received: March 9, 2018; Accepted: August 28, 2018; Published: September 13, 2018. There is a specific gas demand for different soil microbes including bacteria, fungi, and other microorga- nisms . Supervision, Soil pH was determined in water (soil: water = 1: 2.5). Factors affecting microbial biomass and dehydrogenase activity in apple orchard soils with heavy metal accumulation Author(s) ... except for As, increased significantly with decreasing soil pH. where Pi is the ratio of activities on each substrate to the sum of activities on all substrates and ni is the activities on each substrate. Data Availability: All relevant data are within the paper and its Supporting Information files. These community-level physiological profiles (CLPPs) have provided a rapid means for evaluating the structure and species composition of soil microbial communities. PLOS ONE, Sep 2018 Ling Li, Minggang Xu, Mohammad Eyakub Ali, Wenju Zhang, Yinghua Duan, Dongchu Li. Carbon sources can provide energy for microorganisms [46–47], and microorganisms can grow rapidly when they encounter abundant C sources, e.g., the significant increase in MBC in organic materials amendment treatments when compared with the control treatment in the three soils at the end of the 1st month (Fig 2). At the end of the 12th month, the soil organic C (SOC) and C/N ratio of organic materials significantly influenced AWCD, H’, D and U (P < 0.05), and the clay content significantly influenced H’ and D (P < 0.05). When compared with the control, all organic material treatments significantly increased the MBC while only the CM and PM treatments significantly increased the MBN in the three soils (P < 0.05, Fig 2A and 2C). Stepwise multiple regression analysis was applied to determine the key factors influencing microbial properties. Meanwhile, the low pH in the Ferralic Cambisol (pH = 5.2) would reduce the utilization of labile substrate by soil microbes [56–57] because of the toxic exchangeable Al in low pH soil ; however, the integrated effect of SOC, clay content and organic materials amendment could affect the response of microbial biomass to pH as shown by the non-significance of pH in explaining microbial biomass in the stepwise multiple regression analysis. Investigation, All the organic materials were oven-dried at 60°C, and passed through a 2-mm sieve. A one-way ANOVA was used to determine the differences of soil properties, chemical characteristics of organic material, and the above microbial parameters among organic material treatments at each soil. Qiyang Agro-ecosystem of National Field Experimental Station, Hunan, China. The experiment was carried out from June 5, 2012 to June 5, 2013 in the long-term experimental station of the Chinese Academy of Agricultural Sciences, Qiyang County (111°52′32″N, 26°45′12″E), Hunan Province. For more information about PLOS Subject Areas, click Soil available K was extracted with 1 M NH4OAc. Rainfall is usually the limiting factor for microbial biomass in southern Australia (figure 2). The objectives of the present study were therefore (1) to explore the changes in microbial biomass and functional diversity during the decomposition of organic materials in different soil types, and (2) to quantify the contributions of soil type and quality of organic materials to microbial biomass and functional diversity. Soil pH played an important role in shaping microbial community composition [27–28, 30], and the richness of soil bacterial (Shannon index) was lower in the acid soil . Soil and rhizosphere microbial communities in agroecosystems may be affected by soil, climate, plant species, and management. e0203812. Factors affecting soil microbial biomass and functional diversity with the application of organic amendments in three contrasting cropland soils during a field experiment. When compared with the manures, crop residues, in particular straws with low lignin and high C/N ratio, significantly increased the functional diversity indices at both sampling periods (P < 0.05). 1. The readings at 96 h incubation collected by Microlog Rel. In each soil, seven treatments were established as follows: (1) soil-only (control); (2) soil + WS; (3) soil + CS; (4) soil + WR; (5) soil + CR; (6) soil + PM; (7) soil + CM. Rainfall is usually the limiting factor for microbial biomass in southern Australia (figure 2). Roles li dp 1964@sohu.Com The ratio of belowground biomass to aboveground biomass was identified as the main indirect driving force of ecosystem C density by affecting … Soil microbial biomass is a critical factor in ecosystem nutrient cycling [ 16, 17, 18 ], and knowledge about its relation with the ecological stoichiometry of soil is crucial for us to gain insight into the nutrient cycling of terrestrial ecosystems [ 19, 20, 21, 22 ]. Ranjard and Richaume (2001)  found that 40–70% of the bacteria were located in the 2–20 and < 2 μm aggregates. Currently, these Chinese cropland soils have the obvious trend of acidification because of excessive N fertilizer application when compared with those soils 30 years ago . Soil type was the main plot factor and organic material was the subplot factor in a split-plot design with six replicates; three replicates were sampled at the end of the 1st month, and the other three replicates were sampled at the end of the 12th month. Nevertheless, at the end of the 12th month (Fig 2) the crop residue amendments with high C/N ratio induced significantly higher MBC and MBN than the manure amendments. Factors affecting soil microbial biomass and functional diversity with the application of organic amendments in three contrasting cropland soils during a field experiment PLoS One . Thus the microbial biomass was adversely affected by the slightly soluble fractions of Cu accumulated in apple orchard soils, whereas the dehydrogenase activity was affected by the water-soluble and exchangeable Cu of which amount depended on the soil pH. The WS and WR treatments significantly increased the AWCD, Shannon and McIntosh indices in Ferralic Cambisol and Luvic Phaeozem when compared with the control, and all organic material treatments increased the functional diversity indices in Calcaric Cambisol when compared with the control (P < 0.05, Fig 3B, 3D, 3F and 3H). Consequently, the comparison of microbial characteristics in different soil types can improve our understanding of the influence of soil properties on microbes. In China, the Ferralic Cambisol, Calcaric Cambisol and Luvic Phaeozem are the typical intensive cropland soils. Soil and rhizosphere microbial communities in agroecosystems may be affected by soil, climate, plant species, and management. Semantic Scholar is a free, AI-powered research tool for scientific literature, based at the Allen Institute for AI. [Article in Chinese] Li D(1), Wu Z, Chen L, Zhu P, Ren J, Liang C, Peng C, Gao H. Author information: (1)Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China. In agricultural systems, the return of organic materials to the soil is the most prevalent practice to maintain or improve soil fertility. Ling Li. Soil total P and available P were determined by the molybdenum-blue method at a wavelength of 880 nm. The microbial biomass is affected by factors that change the water or carbon content of soil, and include soil type, climate and management practices. Project administration, Organic material quality explained 29.5–50.9% of the variance in MBC and MBN when compared with the minor role of soil type (1.4–9.3%) at the end of the 1st and 12th months, and C/N ratio and total N of organic material were the main parameters. Soil properties had less influence on microbial biomass when compared with the organic material quality, with significant effects only observed at the end of the 1st month (Table 3). https://doi.org/10.1371/journal.pone.0203812.t004. Hence, it explained the lower functional diversity in Luvic Phaeozem than the other two soils. However, such a microbial pool size is transient, and the level of microbial biomass a soil can sustain under a steady-state condition depends on the protective capacity of the soil, which is governed by a dynamic interaction between clay and clay aggregates, soil microbial biomass and soil organic matter (Hassink and Whitmore 1997), and possibly climate (Insam 1990). The effects of biochar on soil microbial and enzyme activities are integrally linked to the potential of biochar in achieving these benefits. The AWCD and McIntosh index was primarily explained by the organic material species (38.4 and 40.3%, respectively), and the Shannon and Simpson indices were primarily explained by soil type (74.4 and 45.3%, respectively). Figure 2:Microbial biomass carbon over a year from a soil near Meckering, Western Australia. The Ferralic Cambisol developed from the quaternary red soil was located in Qiyang County, Hunan Province; this region has a subtropical climate, with an annual average temperature of 18°C and an average annual rainfall of 1255 mm. Soil properties, e.g., organic C and clay content were the predominant influence on microbial functional diversity in particular at the end of the 12th month (61.8–82.8% of the variance explained). Methodology, doi: 10.1371/journal.pone.0203812. While there is a benefit to increased soil C storage for biochars produced at temperatures >200ºC, they have no effect on soil microbial biomass and activity. The quality of applied organic materials can regulate microbial abundance and function [2–4]. National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China, Roles The Calcaric Cambisol developed from alluvial sediments of the Yellow River was located in Yuanyang County, Henan Province; this region has a temperate sub-humid climate, with an annual average temperature of 14.5°C and an average annual rainfall of 450–600 mm. Increased understanding of the size and function of microorganisms after application of different organic materials in different types of agricultural soil is therefore helpful to clarify the effect of organic materials and soil types on microbial characteristics. Soil moisture: Moisture is a critical factor for microbial growth in any environment including the soil. Microbially mediated processes in constructed wetlands are mainly dependent on hydraulic conditions, wastewater properties, including substrate and nutrient quality and availability, filter material or soil type, plants, and different environmental factors. The AWCD is calculated to reflect the utilization of single C sources by soil microorganisms: To evaluate the primary factors influencing microbial parameters, we analyzed MBC, MBN, AWCD, H’, D and U using a two-way analysis of variance (ANOVA) with soil and organic material types as independent factors and permitted to interact. A low biomass quotient or a high respiration quotient is considered to be an indication of stress from, for example, toxicity from metals in sewage sludge … At the end of the 1st month, soil clay content significantly influenced AWCD and U, pH significantly influenced D, and total nitrogen significantly influenced H’ (P < 0.05). https://doi.org/10.1371/journal.pone.0203812.t003. Yes The three surface soils (0–20 cm) were collected using a bucket auger sampler in May 2012, sieved through a 2-mm mesh, and the coarse crop residues, roots, and stones were removed. Copyright: © 2018 Li et al. In addition, soil microbial communities were largely affected by historical factors such as geographic location and soil type due to microbes dwelling in soil [20, 23, 66–67]. Yes Conceptualization, Writing – review & editing, Roles Microbial CLPPs in soil were determined by Biolog Eco plates (Biolog, Hayward, CA, USA). The average well color development (AWCD) and the functional diversity indices including Shannon, Simpson and McIntosh indices were often used to investigate the general structure and functional potential of soil microbial communities [13, 24]. Supervision, At the end of the 1st month, the contributions of soil type and organic material type were significant in explaining the variance in microbial functional diversity (P < 0.05, Table 3). Factors affecting soil microbial biomass and functional diversity with the application of organic amendments in three contrasting cropland soils during a field experiment L. Li, M. Xu, +3 authors Dongchu Li Published 2018 Methodology, https://doi.org/10.1371/journal.pone.0203812.g002. Aliquots of 150 μl of the 10−3 suspension was incubated in each well of Biolog Eco plates at 28°C and the absorbance was measured at 590 nm with an Emax precision microplate reader (Biolog, Hayward, CA, USA). Soil microbial biomass carbon (C) and nitrogen (N) (MBC and MBN) reflect microbial size and soil fertility status, and they act as the living nutrient pool in soil . We thank Catherine Dandie, PhD, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript. The management and environmental factors controlling microbial biomass and community structure were identified in a three-year field experiment. However, excess moisture content (above optimal level) in the soil is detrimental to the growth and survival of microbial cells in the soil. The soil physicochemical properties were shown in Table 1 and the average monthly rainfall and temperature of the study site during the sampling period were shown in Fig 1. https://doi.org/10.1371/journal.pone.0203812.t001, https://doi.org/10.1371/journal.pone.0203812.g001. Yes Competing interests: The authors have declared that no competing interests exist. PLoS ONE 13(9): Conversely, the N limitation was more serious in crop material treatments with high C/N ratio than in manure treatments (S1 Fig) ; the immobilized N induced by crop materials can be recycled in microorganisms with crop materials decomposition [47, 52]. Writing – review & editing, Affiliation The average well color development (AWCD) and the functional diversity indices, including Shannon (H’), Simpson (D) and McIntosh (U) indices, are important diagnostic indicators of soil quality . Microbial biomass C and N were estimated by the difference between the total organic C or total N in the fumigated and non-fumigated extracts with a conversion factor (KEC) of 0.38 and (KEN) of 0.45 [40–41], respectively. A high Pearson correlation coefficient (> 0.6) for PC1 in the organic material treatments was shown in Table 4. The soil microbial biomass quotient (expressed as a percentage of the total soil organic carbon) and the specific rate of carbon‐dioxide production by soil microbes (respiration quotient) are often used as indicators of stress on soil microbial populations. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The quality of organic materials is vital to maintain the microbial functional diversity because of the utilization of labile C or recalcitrant C by distinct microbial communities . These factors influence the species composition of soil microbial communities, but also their activity and functionality. PLoS One. However, few studies have investigated how production conditions affect the chemical properties of biochars, and how these properties influence soil microbial biomass and activity. However, the size and function of microorganisms is different in different soils, for example, high content of soil organic matter is generally associated with high microbial abundance and diversity [7–8]. biotic factors that controlled Rs. Introduction. Lignin is resistant to biodegradation and higher lignin content depresses microbial metabolism; this resulted in the negative correlation between lignin content and the diversity indices (Shannon and Simpson indices) in different organic material treatments at the end of the 1st month [17, 45]. Soil properties were more important than organic material properties in explaining the microbial functional diversity as shown in Table 3 [13, 18–19, 24]. Before the experiment, both Calcaric Cambisol from Zhengzhou and Luvic Phaeozem from Gongzhuling were moved to Qiyang County. Generally, soils with high SOC content had high microbial biomass [25–26, 53–54], and nutritional stress might occur when SOC was less than 1% . Formal analysis, No, Is the Subject Area "Simpson index" applicable to this article? The correlations between different abiotic factors and microbial groups described in this manuscript indicate both the complexity of the soil environment and its sensitivity to various stimuli. Investigation, Soil properties that affect microbial biomass are clay content, soil pH, and organic C content (figure 3). Although manures, with low C/N ratio and high nitrogen content, significantly increased microbial biomass when compared with crop residues at the end of the 1st month (P < 0.05), the crop residues significantly increased the microbial biomass when compared with manures at the end of the 12th month (P < 0.05). In the present study, organic materials amendment might have completely obscured the effect of soil properties on microbial biomass. To better compare the effects of exogenous organic materials and soil type on the microbial characteristics and to eliminate the effect of climate factors, Calcaric Cambisol and Luvic Phaeozem were moved to the subtropical region to accentuate the effects of global warming and soil acidification. Six organic materials (WS: wheat straw, CS: corn straw, WR: wheat root, CR: corn root, PM: pig manure, CM: cattle manure), and three contrasting soils (Ferralic Cambisol, Calcaric Cambisol and Luvic Phaeozem) were chosen. The quality of organic material, e.g., the C availability, the C/N ratio and N content, determines the size of the microbial biomass [13, 43–45] (Table 3). include increased soil carbon (C) sequestration, enhanced microbial activity, and altered soil nitrogen (N) transformations. Yes [Dynamics of microbial biomass P and its affecting factors in a long-term fertilized black soil]. Soil organic carbon (SOC) and microbial biomass carbon (MBC) are important components of soil organic matter (SOM). The WS, CS, WR and CR treatments significantly increased the MBC while only the WS and CS treatments significantly increased the MBN when compared with the control in the three soils (P < 0.05, Fig 2B and 2D). Generally, soil N immobilization occurred with organic materials amendment [47, 51]. Soil pH plays an important role in shaping microbial community composition [27–30]; soil pH was negatively correlated with soil biomass and positively correlated with AWCD [11, 13]. ODR is affected by several factors. 2. Soil texture can also affect the soil nutrient status and water content, thus affecting the living environment and metabolic activity of microorganisms [31–32]. Factors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale David J. Müller et al. Conceptualization, Soil microbial functional diversity is linked with the stability of soil microbial communities and levels of soil biodiversity . : Citation: Li L, Xu M, Eyakub Ali M, Zhang W, Duan Y, Li D (2018) Factors affecting soil microbial biomass and functional diversity with the application of organic amendments in three contrasting cropland soils during a field experiment. At the end of the 1st month, the increase in AWCD and McIntosh index with increased clay content was because silt and clay particles generally supported larger and more diverse microbial communities than sand particles . The integrated effect of soil type and organic material amendment significantly (P < 0.05) affected the microbial functional diversity. Factors affecting soil microbial biomass and functional diversity with the application of organic amendments in three contrasting cropland soils during a field experiment Li, Ling Xu, Minggang At the end of the 12th month, the variance in MBC and MBN was primarily explained by the organic material type, and the contribution of the organic material type was significant and explained 45.3% of the variance in MBC and 29.5% of the variance in MBN (P < 0.05, Table 3). Microbial biomass carbon and Shannon’s diversity index after amendment with labile organic materials with low lignin content were significantly higher than that after amendment with recalcitrant organic materials with high lignin content [16–17]. 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