scholarly journals Microbiological activity and carbon mineralization in pampean soils with different agricultural use intensity

Author(s):  
Ricardo A Castro-Huerta ◽  
Fernando R Momo ◽  
Liliana B Falco ◽  
César A Di Ciocco ◽  
Carlos E Coviella

The processes involved in the flows of matter and energy of terrestrial ecosystems depends heavily on soil biological activity, the current conventional agricultural managements could alter the biological mechanisms involved in decomposition and nutrient cycling in agroecosystems. The aim of this study was to compare the activity levels and soil microbial biomass between different agricultural pampean soil uses and its relationship to carbon mineralization. 25 years of agricultural use were compared with 25 years of ecological reserve naturalized where each agroecosystem soil were collected at 61 - 125 - 183 - 236 - 302 - 368 - 431 - 488 days for measuring their moisture, organic matter, enzymatic activity, microbial biomass carbon, soil respiration, metabolic quotient, microbial quotient and carbon mineralization rate. The distance between agroecosystems is less than 800 m, thus assuming the same soil and climatic conditions. The data were evaluated by Friedman test finding significant differences in moisture, organic matter, enzymatic activity, soil respiration y microbial quotient (p< 0.01). Difference was also found in the microbial mineralization rate of carbon (p< 0.1).

2015 ◽  
Author(s):  
Ricardo A Castro-Huerta ◽  
Fernando R Momo ◽  
Liliana B Falco ◽  
César A Di Ciocco ◽  
Carlos E Coviella

The processes involved in the flows of matter and energy of terrestrial ecosystems depends heavily on soil biological activity, the current conventional agricultural managements could alter the biological mechanisms involved in decomposition and nutrient cycling in agroecosystems. The aim of this study was to compare the activity levels and soil microbial biomass between different agricultural pampean soil uses and its relationship to carbon mineralization. 25 years of agricultural use were compared with 25 years of ecological reserve naturalized where each agroecosystem soil were collected at 61 - 125 - 183 - 236 - 302 - 368 - 431 - 488 days for measuring their moisture, organic matter, enzymatic activity, microbial biomass carbon, soil respiration, metabolic quotient, microbial quotient and carbon mineralization rate. The distance between agroecosystems is less than 800 m, thus assuming the same soil and climatic conditions. The data were evaluated by Friedman test finding significant differences in moisture, organic matter, enzymatic activity, soil respiration y microbial quotient (p< 0.01). Difference was also found in the microbial mineralization rate of carbon (p< 0.1).


2012 ◽  
Vol 599 ◽  
pp. 124-127
Author(s):  
Cheng Hu Zhang ◽  
Ting Ting Song ◽  
Ju Liu ◽  
Hui Juan Xia ◽  
Jian Zhu Wang

Natural restoration slope and vegetation-growing concrete slope were selected as plots. Soil water content (SWC), pH, and soil organic matter, total nitrogen content (TN), total organic carbon (TOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), basal respiration, microbial quotient and metabolic quotient (qCO2) were analyzed. The main results show that: Soil organic matter, TN and MBC of 0-10 cm soil in the natural restoration slope are significantly lower than that in the vegetation-growing concrete slopes at 0.05 level. Both MBC and MBN show a highly significant positive correlation with soil organic matter and TN. Microbial quotient shows a highly significant negative correlation with TOC and MBN, and shows a significant negative correlation with MBC. The qCO2 shows a highly significant negative correlation with pH, and a significant negative correlation with MBC. The vegetation-growing concrete technology can improve the soil ecosystem in the impaired slope.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5857 ◽  
Author(s):  
Dulce Flores-Rentería ◽  
Ana Rincón ◽  
Teresa Morán-López ◽  
Ana-Maria Hereş ◽  
Leticia Pérez-Izquierdo ◽  
...  

We studied key mechanisms and drivers of soil functioning by analyzing soil respiration and enzymatic activity in Mediterranean holm oak forest fragments with different influence of the agricultural matrix. For this, structural equation models (SEM) were built including data on soil abiotic (moisture, temperature, organic matter, pH, nutrients), biotic (microbial biomass, bacterial and fungal richness), and tree-structure-related (basal area) as explanatory variables of soil enzymatic activity and respiration. Our results show that increased tree growth induced by forest fragmentation in scenarios of high agricultural matrix influence triggered a cascade of causal-effect relations, affecting soil functioning. On the one hand, soil enzymatic activity was strongly stimulated by the abiotic (changes in pH and microclimate) and biotic (microbial biomass) modifications of the soil environment arising from the increased tree size and subsequent soil organic matter accumulation. Soil CO2emissions (soil respiration), which integrate releases from all the biological activity occurring in soils (autotrophic and heterotrophic components), were mainly affected by the abiotic (moisture, temperature) modifications of the soil environment caused by trees. These results, therefore, suggest that the increasing fragmentation of forests may profoundly impact the functioning of the plant-soil-microbial system, with important effects over soil CO2emissions and nutrient cycling at the ecosystem level. Forest fragmentation is thus revealed as a key albeit neglected factor for accurate estimations of soil carbon dynamics under global change scenarios.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mara Regina Moitinho ◽  
Daniel De Bortoli Teixeira ◽  
Elton da Silva Bicalho ◽  
Alan Rodrigo Panosso ◽  
Antonio Sergio Ferraudo ◽  
...  

AbstractThe spatial structure of soil CO2 emission (FCO2) and soil attributes are affected by different factors in a highly complex way. In this context, this study aimed to characterize the spatial variability patterns of FCO2 and soil physical, chemical, and microbiological attributes in a sugarcane field area after reform activities. The study was conducted in an Oxisol with the measurement of FCO2, soil temperature (Ts), and soil moisture (Ms) in a regular 90 × 90-m grid with 100 sampling points. Soil samples were collected at each sampling point at a depth of 0–0.20 m to determine soil physical (density, macroporosity, and microporosity), particle size (sand, silt, and clay), and chemical attributes (soil organic matter, pH, P, K, Ca, Mg, Al, H + Al, cation exchange capacity, and base saturation). Geostatistical analyses were performed to assess the spatial variability and map soil attributes. Two regions (R1 and R2) with contrasting emission values were identified after mapping FCO2. The abundance of bacterial 16S rRNA, pmoA, and nifH genes, determined by real-time quantitative PCR (qPCR), enzymatic activity (dehydrogenase, urease, cellulase, and amylase), and microbial biomass carbon were determined in R1 and R2. The mean values of FCO2 (2.91 µmol m−2 s−1), Ts (22.6 °C), and Ms (16.9%) over the 28-day period were similar to those observed in studies also conducted under Oxisols in sugarcane areas and conventional soil tillage. The spatial pattern of FCO2 was similar to that of macropores, air-filled pore space, silt content, soil organic matter, and soil carbon decay constant. No significant difference was observed between R1 and R2 for the copy number of bacterial 16S rRNA and nifH genes, but the results of qPCR for the pmoA gene presented differences (p < 0.01) between regions. The region R1, with the highest FCO2 (2.9 to 4.2 µmol m−2 s−1), showed higher enzymatic activity of dehydrogenase (33.02 µg TPF g−1 dry soil 24 h−1), urease (41.15 µg NH4–N g−1 dry soil 3 h−1), amylase (73.84 µg glucose g−1 dry soil 24 h−1), and microbial biomass carbon (41.35 µg C g−1 soil) than R2, which had the lowest emission (1.9 to 2.7 µmol m−2 s−1). In addition, the soil C/N ratio was higher in R2 (15.43) than in R1 (12.18). The spatial pattern of FCO2 in R1 and R2 may not be directly related to the total amount of the microbial community (bacterial 16S rRNA) in the soil but to the specific function that these microorganisms play regarding soil carbon degradation (pmoA).


2017 ◽  
Vol 38 (4) ◽  
pp. 1765
Author(s):  
Larissa Castro Diógenes ◽  
José Ferreira Lustosa Filho ◽  
Alessandro Franco Torres da Silva ◽  
Júlio César Azevedo Nóbrega ◽  
Rafaela Simão Abrahão Nóbrega ◽  
...  

The aim of this study was to evaluate microbial biomass and total organic carbon and nitrogen of an irrigated Quartzarenic Neosol cultivated with two cowpea cultivars in Bom Jesus, Piauí, Brazil. The experiment was conducted in a randomized experimental block design in split plots. The plots consist of two cowpea cultivars (Aracê and Tumucumaque) and the subplots were composed of five different irrigation regimes (L1 = 108.2; L2 = 214.7; L3 = 287.9; L4 = 426.1, and L5 = 527.7 mm). Soil samples were collected at a depth of 0-0.20 m in order to evaluate basal soil respiration, microbial biomass carbon, metabolic quotient, microbial quotient, content, and storage of soil carbon and nitrogen. Basal soil respiration, microbial biomass carbon, microbial metabolic quotient, and microbial quotient are influenced by the interaction between cowpea cultivars and irrigation. The cultivar Aracê showed greater stimulus to the microbial community, while the irrigation regimes with 214.7 and 287.9 mm (60 and 90% of ETo, respectively) provided the best moisture conditions for microbial activities.


2015 ◽  
Vol 12 (22) ◽  
pp. 6751-6760 ◽  
Author(s):  
Z. H. Zhou ◽  
C. K. Wang

Abstract. Microbial metabolism plays a key role in regulating the biogeochemical cycle of forest ecosystems, but the mechanisms driving microbial growth are not well understood. Here, we synthesized 689 measurements on soil microbial biomass carbon (Cmic) and nitrogen (Nmic) and related parameters from 207 independent studies published up to November 2014 across China's forest ecosystems. Our objectives were to (1) examine patterns in Cmic, Nmic, and microbial quotient (i.e., Cmic / Csoil and Nmic / Nsoil rates) by climate zones and management regimes for these forests; and (2) identify the factors driving the variability in the Cmic, Nmic, and microbial quotient. There was a large variability in Cmic (390.2 mg kg−1), Nmic (60.1 mg kg−1, Cmic : Nmic ratio (8.25), Cmic / Csoil rate (1.92 %), and Nmic / Nsoil rate (3.43 %) across China's forests. The natural forests had significantly greater Cmic (514.1 mg kg−1 vs. 281.8 mg kg−1) and Nmic (82.6 mg kg−1 vs. 39.0 mg kg−1) than the planted forests, but had less Cmic : Nmic ratio (7.3 vs. 9.2) and Cmic / Csoil rate (1.7 % vs. 2.1 %). Soil resources and climate together explained 24.4–40.7 % of these variations. The Cmic : Nmic ratio declined slightly with Csoil : Nsoil ratio, and changed with latitude, mean annual temperature and precipitation, suggesting a plasticity of microbial carbon-nitrogen stoichiometry. The Cmic / Csoil rate decreased with Csoil : Nsoil ratio, whereas the Nmic / Nsoil rate increased with Csoil : Nsoil ratio; the former was influenced more by soil resources than by climate, whereas the latter was influenced more by climate. These results suggest that soil microbial assimilation of carbon and nitrogen are jointly driven by soil resources and climate, but may be regulated by different mechanisms.


2015 ◽  
Vol 12 (14) ◽  
pp. 11191-11216 ◽  
Author(s):  
Z. H. Zhou ◽  
C. K. Wang

Abstract. Microbial metabolism plays a key role in regulating the biogeochemical cycle of forest ecosystems, but the mechanisms driving microbial growth are not well understood. Here, we synthesized 689 measurements on soil microbial biomass carbon (Cmic) and nitrogen (Nmic) and related parameters from 207 independent studies published during the past 15 years across China's forest ecosystems. Our objectives were to (1) examine patterns in Cmic, Nmic, and microbial quotient (i.e., Cmic / Csoil and Nmic / Nsoil rates) by climate zones and management regimes for these forests; and (2) identify the factors driving the variability in the Cmic, Nmic, and microbial quotient. There was a large variability in Cmic (390.2 mg kg−1), Nmic (60.1 mg kg−1), Cmic : Nmic ratio (8.25), Cmic / Csoil rate (1.92 %), and Nmic / Nsoil rate (3.43 %) across China's forests, with coefficients of variation varying from 61.2 to 95.6 %. The natural forests had significantly greater Cmic and Nmic than the planted forests, but had less Cmic : Nmic ratio and Cmic / Csoil rate. Soil resources and climate together explained 24.4–40.7 % of these variations. The Cmic : Nmic ratio declined slightly with the Csoil : Nsoil ratio, and changed with latitude, mean annual temperature and precipitation, suggesting a plastic homeostasis of microbial carbon-nitrogen stoichiometry. The Cmic / Csoil and Nmic / Nsoil rates were responsive to soil resources and climate differently, suggesting that soil microbial assimilation of carbon and nitrogen be regulated by different mechanisms. We conclude that soil resources and climate jointly drive microbial growth and metabolism, and also emphasize the necessity of appropriate procedures for data compilation and standardization in cross-study syntheses.


2018 ◽  
Vol 2 ◽  
pp. 96-101
Author(s):  
Dil Kumar Limbu ◽  
Madan Koirala

The soil microbial biomass carbon to soil organic carbon ratio is a useful measure to monitor soil organic matter and serves as a sensitive index than soil organic carbon alone. Thus, the objective of this study is to identify and quantify the present status of ratio of soil microbial biomass carbon to soil organic carbon in Himalayan rangeland and to make recommendations for enhancing balance between microbial carbon and organic carbon of the soil. To meet the aforementioned objective, a field study was conducted from 2011 to 2013 following the Walkley-Black, Chromic acid wet oxidation method, and chloroform fumigation method for analysis of microbial carbon and organic carbon respectively. The study showed that the heavily grazed plot had significantly less value of ratio than occasionally grazed and ungrazed plots. The ratio was significantly high on legume seeding plot compared to nonlegume plot, but the ratio was independent of soil depth. Soil microbial biomass appeared to be more responsive than soil organic matter.


2017 ◽  
Vol 41 (4) ◽  
pp. 1705-1722 ◽  
Author(s):  
Mohammad I. Al-Wabel ◽  
Adel Rabie A. Usman ◽  
Abdullah S. Al-Farraj ◽  
Yong Sik Ok ◽  
Adel Abduljabbar ◽  
...  

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