Thermal response of soil microbial respiration is positively associated with labile carbon content and soil microbial activity

ABSTRACT Peanut production in Zambia is often characterized by low yields and high aflatoxin incidence in harvested kernels. Soil amendments such as farmyard manure have shown potential to increase yields and reduce pre-harvest aflatoxin incidence. The aim of the current study was to evaluate the effects of composted cattle manure on soil properties that relate to yield and pre-harvest aflatoxin contamination of peanut kernels. Research evaluated the effects of composted cattle manure on soil respiration, plant-available water (PAW), peanut yield and pre-harvest aflatoxin contamination in a field experiment conducted in two successive rain-fed cropping seasons starting in December, 2015 and ending in April 2017, in Chongwe District, Zambia. Six (6) levels of compost were incorporated into the top 10 cm of the soil at rates of 0, 4.5, 12.0, 19.5, 27.0, and 34.5 metric tons/ha 1 wk before planting. There was a strong positive relationship between levels of compost and soil microbial respiration (R2=0.84) and PAW (R2=0.86). Secondly, compost manure was associated with increases in pod (R2=0.65) and kernel (R2=0.61) yield. The kernel yield potential of the planted cultivar was achieved at the rate of 12 metric tons per ha. Thirdly, there was a reduction in total aflatoxin levels with increasing levels of compost (R2=0.85). The improvement in peanut yield and the decrease in aflatoxin concentrations in kernels can be attributed to the improvement in soil moisture retention capacity and soil microbial activity arising from manure amendments. This study demonstrated the potential of compost manure to increase soil microbial activity, PAW, peanut yield and minimize aflatoxin contamination at field level.

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Responses of Soil Microbial Activity to Swine Manure Applications

Journal of Agricultural Science ◽

10.5539/jas.v12n9p199 ◽

2020 ◽

Vol 12 (9) ◽

pp. 199

Author(s):

Maria Josiane Martins ◽

Tânia Santos Silva ◽

Igor Paranhos Caldas ◽

Geovane Teixeira de Azevedo ◽

Isabelle Carolyne Cardoso ◽

...

Keyword(s):

Microbial Biomass ◽

Microbial Activity ◽

Microbial Respiration ◽

Swine Manure ◽

Soil Microbial Activity ◽

Soil Microbial ◽

Liquid Swine Manure ◽

Randomized Design ◽

Set Up ◽

The Impact

The allocation of the large amount of swine waste from farms is an international concern. An efficient way of managing such waste is its use in farming. It is already known that the incorporation of organic waste into the soil significantly increases the microbial population. Therefore, the objective was to evaluate the impact of the use of swine manure on the soil microbiota in a Eutrophic Oxisol. The experiment was set up in a completely randomized design in a 6 × 4 factorial scheme (sixconcentrations of swine manure and four evaluation periods) with four replications. We evaluate the following characteristics: microbial respiration (C-CO2), microbial biomass (µC g-1 soil) and pH.: microbial respiration (C-CO2), microbial biomass (µC g-1 soil) and pH. A significant effect was found in the interaction between concentrations and time of incubation (p < 0.05) of swine manure on microbial activity in the soil. The amount of microbial carbon increased as a function of increased levels of liquid swine manure. No interaction was observed between concentrations and time of incubation for the pH. The evaluation of the isolated factors allowed to observe that the pH decreased as the doses of manure were incremented. Higher and lower pH values were found after 5 and 30 days of incubation. The application of liquid swine manure up to 6000 L ha-1 increases the release of CO2 and carbon in the microbial biomass. The applications of liquid swine manure cause a gradual reduction in soil pH.

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Type and quantity of biochar influenced soil microbial activity and carbon priming effect

Semina Ciências Agrárias ◽

10.5433/1679-0359.2019v40n4p1405 ◽

2019 ◽

Vol 40 (4) ◽

pp. 1405

Author(s):

José Ilmar Tínel de Carvalho Junior ◽

Maria Isidória Silva Gonzaga ◽

André Quintão de Almeida ◽

Jady Araújo ◽

Lúcia Catherinne Oliveira Santos

Keyword(s):

Microbial Activity ◽

Priming Effect ◽

Microbial Respiration ◽

Soil Microbial Activity ◽

Soil Microbial ◽

Randomized Design ◽

Different Types ◽

Completely Randomized Design ◽

Set Up ◽

Bagasse Biochar

Biochar has shown much potential to be used as soil amendment and conditioner as well as an effective alternative to waste disposal. However, the effect of biochar on soil organic matter varies according to the type of feedstock. This study aimed to evaluate the influence of different types and rates of application of biochar on soil microbial activity and on soil carbon priming effect. The incubation experiment was set up as a completely randomized design in a 2 x 5 factorial scheme, with two types of biochar (coconut husk and orange bagasse) and five rates of application (0, 5, 10, 15 and 30 t ha-1), with three replications. Soil microbial activity was evaluated through the concentration of CO2 released from the soil during a period of 130 days. Carbon priming effect was determined based on the CO2 respired in the biochar treated soil and in the control soil. Both biochars increased the total oxidizable carbon in the soil when they were applied at 30 t ha-1, however, the orange bagasse biochar was more effective than the coconut biochar. Coconut biochar increased the cumulative soil microbial respiration at all rates of application during the incubation period, therefore, it contributed to a positive carbon priming effect and should be applied with caution to avoid excessive loss of carbon from the soil. Orange bagasse biochar had little influence on the cumulative CO2 emission, except at 15 t ha-1, which increased soil microbial activity.

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Impacts of Heavy Metals on Soil Microbial Activity

Journal of Environment and Ecology ◽

10.5296/jee.v11i1.16444 ◽

2020 ◽

Vol 11 (1) ◽

pp. 19

Author(s):

Ana Paula Justiniano Régo ◽

Valdemar Luiz Tornisielo

Keyword(s):

Heavy Metals ◽

Microbial Activity ◽

Soil Quality ◽

Microbial Respiration ◽

Soil Microbial Activity ◽

Dam Failure ◽

Soil Microbial ◽

Minas Gerais State ◽

Environmental Balance

Concern about soil quality has been increasing due to environmental impacts from anthropogenic actions. The imbalance between its components alters activities in ecosystems. One of the main actions affecting soil quality is the presence of heavy metals, impairing the functioning of the ecosystem. This work evaluated the impacts of metal-contaminated soil on microbial activity after dam failure in Minas Gerais State, Brazil. Microbial respiration measurements and colony quantifications were used for evaluations. Thus, it is hoped that through these bioindicators, we can assess the quality of the environment and from these biostimulators restore the environmental balance, benefiting local communities affected by the disaster. After microbial biostimulation of the soil, there was an increase in the number of bacterial colonies as well as greater accumulation of CO2 over the days. Thus, the addition of nutrients to the metal-impacted soil was essential for initiating the restoration of the affected ecosystem equilibrium.

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Dehydrogenase Activity in a Litter Manipulation Experiment in Temperate Forest Soil

Acta Silvatica et Lignaria Hungarica ◽

10.2478/aslh-2013-0002 ◽

2013 ◽

Vol 9 (1) ◽

pp. 25-33 ◽

Cited By ~ 11

Author(s):

Zsuzsa Veres ◽

Zsolt Kotroczó ◽

Kornél Magyaros ◽

János Attila Tóth ◽

Béla Tóthmérész

Keyword(s):

Enzyme Activity ◽

Microbial Activity ◽

Dehydrogenase Activity ◽

Enzyme Activities ◽

Soil Microbial Activity ◽

Litter Production ◽

Labile Carbon ◽

Soil Microbial ◽

Litter Manipulation ◽

Soil Dehydrogenase Activity

Abstract Soil enzyme activities are “sensors” of soil organic matter (SOM) decomposition since they integrate information about microbial status and physico-chemical condition of soils. We measured dehydrogenase enzyme activity in a deciduous temperate oak forest in Hungary under litter manipulation treatments. The Síkfőkút Detritus Input and Removal Treatments (DIRT) Project includes treatments with doubling of leaf litter and woody debris inputs as well as removal of leaf litter and trenching to prevent root inputs. We hypothesized that increased detrital inputs increase labile carbon substrates to soils and would increase enzyme activities particularly that of dehydrogenase, which has been used as an indicator of soil microbial activity. We also hypothesized that enzyme activities would decrease with detritus removal plots and decrease labile carbon inputs to soil. After ten years of treatments, litter removal had a stronger effect on soil dehydrogenase activity than did litter additions. These results showed that in this forest ecosystem the changed litter production affected soil microbial activity: reduced litter production decreased the soil dehydrogenase activity; increased litter production had no significant effect on the enzyme activity.

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Evaluating carbon dynamics and microbial activity in arctic soils under warmer temperatures

Canadian Journal of Soil Science ◽

10.4141/cjss07060 ◽

2008 ◽

Vol 88 (1) ◽

pp. 31-44 ◽

Cited By ~ 12

Author(s):

Maren Oelbermann ◽

Michael English ◽

Sherry L Schiff

Keyword(s):

Microbial Activity ◽

Soil Microorganisms ◽

Microbial Respiration ◽

Soil Microbial Activity ◽

Phase 2 ◽

Metabolic Diversity ◽

Soil Horizons ◽

Organic C ◽

Soil Microbial ◽

Arctic Soils

A large portion of carbon (C) is stored in the world’s soils, including those of peatlands, wetlands and permafrost. However, there is disagreement regarding the effects of climate change on the rate of organic matter decomposition in permafrost soils of the arctic. In this study it was hypothesized that soil exposed to a higher ambient temperature would have a greater flux of CO2 as well as a change in the metabolic diversity of culturable soil microorganisms. To evaluate this hypothesis we determined soil C dynamics, soil microbial respiration and activity, and 13C and 15N fractionation in laboratory incubations (at 14 and 21°C) for an organic-rich soil (Mesic Organic Cryosol) and a mineral soil (Turbic Cryosol) collected at the Daring Lake Research Station in Canada’s Northwest Territories. Soil organic C (SOC) and nitrogen (N) stocks (g m-2) and concentration (%) were significantly different (P < 0.05) between soil horizons for both soil types. Stable isotope analysis showed a significant enrichment in δ13C and δ15N with depth and a depletion in δ13C and δ15N with increasing SOC and N concentration. In laboratory incubations, microbial respiration showed three distinct phases of decomposition: a phase with a rapidly increasing rate of respiration (phase 1), a phase in which respiration reached a peak midway through the incubation (phase 2), and a phase in the latter part of the incubation in which respiration stabilized at a lower flux than that of the first phase (phase 3). Fluxes of CO2 were significantly greater at 21°C than at 14°C. The δ13C of the evolved CO2 became significantly enriched with time with the greatest enrichment occurring in phase 2 of the incubation. Soil microbial activity, as measured using Biolog EcoplatesTM, showed a significantly greater average well color development, richness, and Shannon index at 21°C; again the greatest change occurred in phase 2 of the incubation. Principal component analysis (PCA) of the Biolog data also showed a change in the distinct clustering of the soil microbial activity, showing that C sources from the soil were metabolized differently with time at 21 than at 14°C, and between soil horizons. Our results show that Canadian arctic soils contain large stores of C, which readily decompose, and that substantial increases in CO2 emissions and changes in the metabolic diversity of culturable soil microorganisms may occur when ambient temperatures increase from 14 to 21°C. Key words: CO2 flux, C fractionation, global warming, soil organic C and N, stable isotopes

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