scholarly journals Aerobic microbial activity in four tropical earthworm-soil systems. A mesocosm experiment

Soil Research ◽  
2014 ◽  
Vol 52 (6) ◽  
pp. 584 ◽  
Author(s):  
J. Sierra ◽  
G. Loranger-Merciris ◽  
L. Desfontaines ◽  
M. Boval
Keyword(s):  
Microbial Activity ◽  
Tropical Soils ◽  
Mesocosm Experiment ◽  
P Availability ◽  
N Mineralisation ◽  
Organic C ◽  
Aerobic Activity ◽  
Aerobic Processes ◽  
C Mineralisation ◽  
Earthworm Activity

Soil organic matter (SOM) quality and carbon (C) availability may be major features influencing the effect of earthworms on the aerobic processes in clayey tropical soils. In this study, we assessed the effect of an anecic (Polypheretima elongata), an endogeic (Pontoscolex corethrurus) and an epigeic (Eudrilus eugeniae) earthworm on the aerobic microbial activity of two tropical soils, a calcic Vertisol and an acid Ferralsol, with clay content >70% and very different organic C content and SOM stability. The soil–earthworm interaction was studied in a 6-month mesocosm experiment in a greenhouse using soils with and without (control soil) earthworm addition. Potential C mineralisation, actual net nitrogen (N) mineralisation and dehydrogenase activity (DHA), as indicators of the aerobic activity of the soils, and phosphorus (P) availability were determined during the trial. DHA was used as an indicator of the global aerobic activity. Earthworms had little effect on potential C mineralisation but significantly increased actual net N mineralisation. The increase in N mineralisation in the Vertisol was twice as great as, and longer (6 v. 3 months) than for the Ferralsol. Differences between soils for N mineralisation were associated with a less recalcitrant SOM in the Vertisol. Available P increased 10% in the earthworm treatments. Earthworm activity improved N and P availability. DHA was 15 times higher for the Vertisol than for the Ferralsol, but the positive effect of earthworms on DHA was greater for the Ferralsol. This effect was greater for E. eugeniae, probably because of surface burrows generated by this epigeic earthworm, which favoured oxygen entry into the soil. Differences between the two soils were greater for DHA than for C and N mineralisation, and this was observed for the control soils as well as for the earthworm treatments. This indicates that earthworm activity modified the rate of the aerobic processes but it did not affect the intrinsic biological properties of these tropical soils, which were controlled mainly by SOM quality and C availability.

scholarly journals Variação de atributos do solo ao longo de três topossequências no planalto do Rio Grande do Sul (Variation of soil attribute along of three toposequence in the Rio Grande do Sul plateau)

2017 ◽  
Vol 10 (5) ◽  
pp. 1435
Author(s):  
Viviane Capoane ◽  
Tales Tiecher ◽  
Danilo Rheinheimer dos Santos
Keyword(s):  
Land Use ◽  
Soil Properties ◽  
Soil Profile ◽  
Rio Grande ◽  
P Availability ◽  
Rio Grande Do Sul ◽  
Organic C ◽  
Topographic Position ◽  
Natural Grasslands ◽  
Total P

Este trabalho investigou os efeitos da topografia e das práticas de uso e manejo do solo na variabilidade de alguns atributos do solo ao longo de três topossequências localizadas no planalto do Rio Grande do Sul. As topossequências (Tps) estão inseridas em uma bacia hidrográfica situada no município de Júlio de Castilhos. Na Tp1 foram definidos quatro pontos de amostragem e na Tp2 e Tp3, cinco pontos. Em cada perfil foram coletadas amostras em 5 camadas de solo (0‒5, 5‒10, 10‒20, 20‒40 e 40‒60 cm). Em laboratório foram determinados os atributos: densidade, argila, pH em água, carbono (C) orgânico total, fósforo (P) total, P orgânico total, P disponível, óxidos de ferro (Fe) e alumínio (Al) cristalinos e amorfos. Os resultados encontrados mostram que o movimento de sedimentos em superfície e através do perfil do solo é controlado pela posição, forma e declividade da encosta e, pelas atividades antrópicas como o uso e manejo do solo e aplicação de fertilizantes. Considerando as classes de uso da terra, os maiores teores de C e P (total, orgânico e disponível) foram obtidos na área úmida, seguido da lavoura e campo nativo. Considerando a posição na encosta os teores de C e P foram maiores na baixada seguido da base da encosta, topo e meia encosta. A condição hidromórfica ao longo das topossequências desempenhou um papel importante na disponibilidade de P, acúmulo C orgânico total e solubilização dos óxidos de Fe e Al. A B ST R A C TThis work investigated the effects of topography and land use and soil management practices on the variability of some soil properties along three toposequences located in the Rio Grande do Sul plateau, Southern Brazil. The toposequences (Tps) evaluated are from a watershed located in the municipality of Júlio de Castilhos. Soil samples were taken in four points in Tp1 and in five points in Tp2 and Tp3. In each point samples were taken at five depths (0‒5, 5‒10, 10‒20, 20‒40, and 40‒60 cm). The soil properties evaluated were soil density, clay, pH in water, total organic carbon (C), total phosphorus (P), total organic P, available P, and amorphous and crystalline iron (Fe) and aluminum (Al) oxides. Results show that the transport of sediments on the surface and through the soil profile is controlled by topographic position, landform, slope, and also by the anthropic activities such as the use and management of the soil and the application of fertilizers. Considering the classes of land use, the highest levels of C and P (total, organic and available) were obtained in the wetlands, followed by the crop fields and natural grasslands. Considering the topographic position, the contents of C and P were higher in the floodplain followed by the base of the slope, top and middle slope. Hydromorphic conditions along the toposequences played an important role in P availability, total organic C accumulation and solubilization of Fe and Al oxides.keywords: Land use, topographic position, soil profile, soil properties. 

Impact of microbial activity on the mobility of metallic elements (Fe, Al and Hg) in tropical soils

Geoderma ◽  
2019 ◽  
Vol 334 ◽  
pp. 146-154 ◽  
Author(s):  
C. Balland-Bolou-Bi ◽  
E.B. Bolou-Bi ◽  
V. Alphonse ◽  
S. Giusti-Miller ◽  
M.D. Jusselme ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Tropical Soils ◽  
Metallic Elements

Sulfur forms in bulk soils and alkaline soil extracts of tropical mountain ecosystems in northern Thailand

Soil Research ◽  
2002 ◽  
Vol 40 (1) ◽  
pp. 161 ◽  
Author(s):  
A. Möller ◽  
K. Kaiser ◽  
N. Kanchanakool ◽  
C. Anecksamphant ◽  
W. Jirasuktaveekul ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Tropical Soils ◽  
Forest Site ◽  
Alkaline Soil ◽  
Northern Thailand ◽  
Total N ◽  
Soil Extracts ◽  
Organic C ◽  
Organic S

Sulfur, besides phosphorus, is crucial for the nutrition of plants on tropical soils. Its availability is closely related to the turnover of soil organic matter. To get a better insight into transformation of soil S forms during the decomposition of organic matter, we studied inorganic and organic S pools in bulk samples and alkaline extracts of soils under different land uses representative of the tropical highlands of northern Thailand. Samples were taken from a cabbage cultivation, a Pinus reforestation, a secondary forest, and a primary forest. Total S ranged from 483 549 mg/kg in the subsoil to 1909 376 mg/kg in the organic layers, which is relatively high for tropical soils. The major S component in soil was organic S, comprising 75–99% of total S. Organic S was significantly correlated with total S, organic C, and total N, indicating that there is a close relationship between C, N, and S cycling in soil. C-bonded S was the predominant form in the topsoils (35–99% of total S) but its presence decreased with soil depth. The maximum concentrations of ester SO4-S were found in the A horizons (128 49 mg/kg), whereas the concentrations of inorganic SO4-S were small in all horizons. Compared with the forest site, the cabbage cultivation site was strongly depleted in S. C-bonded S was more depleted than ester SO4-S. A comparison of the S forms in NaOH extracts with S forms in bulk soil and C forms as indicated by 13C-NMR spectroscopy showed (i) that the extracts were very representative of soil organic S fractions and (ii) that ester SO4-S was mainly associated with O-substituted aliphatic C. In contrast, C-bonded S seemed to be connected to more-or-less all C binding types. transformation of soil organic matter, sulfate.

scholarly journals The impact of windthrow and fire disturbances on selected soil properties in the Tatra National Park

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S74-S80 ◽  
Author(s):  
E. Gömöryová ◽  
K. Střelcová ◽  
J. Škvarenina ◽  
J. Bebej ◽  
D. Gömöry
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
National Park ◽  
Soil Microbial Activity ◽  
N Mineralisation ◽  
Soil Microbial ◽  
Microbial Characteristics ◽  
Fire Disturbances ◽  
Tatra National Park ◽  
The Impact

: In November 2004, forest stands in the Tatra National Park (TANAP) were affected by windthrow and in July 2005, the wildfire broke out on a part of the affected area. The objective of this study is to evaluate the impact of the windthrow and fire disturbances on soil microbial activity. Basal and potential soil respiration, N-mineralisation, catalase activity, soil microbial biomass, and cellulase activity were measured in soil samples taken from the A-horizon (depth of 0–10 cm) along 100 m transects established on 4 plots (reference site, burnt, non-extracted, and extracted sites) in October 2006. Some soil microbial characteristics exhibited a high spatial variability, especially microbial biomass and N-mineralisation. Significant differences in soil microbial characteristics (especially basal soil respiration and catalase activity) between plots were found. Generally, the highest microbial activity was revealed on the plot affected by fire. Soil microbial activity was similar on the extracted and non-extracted sites.

What controls microbial growth in tropical soils? The role of carbon and phosphorus.

2020 ◽  
Author(s):  
Christian Ranits ◽  
Lucia Fuchslueger ◽  
Leandro Van Langenhove ◽  
Ivan Janssens ◽  
Josep Peñuelas ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Microbial Communities ◽  
Microbial Growth ◽  
Microbial Respiration ◽  
Tropical Soils ◽  
Microbial Biomass C ◽  
P Availability ◽  
Respiration Activity ◽  
Respiration Rates ◽  
C And N

<p>Tropical forest ecosystems are important components of global biogeochemical cycling. Many tropical rainforests grow in old and highly weathered soils, depleted in phosphorus (P) and net primary productivity in tropical forests is often limited by P availability. It is unclear, however, if heterotrophic microbial communities in tropical soils are also limited by P or rather by carbon (C). Elemental limitations of microorganisms in soil have often been approached by measurements of respiration rates in response to additions of nutrients or carbon. However, it has been argued lately, that microbial growth rather than respiration should be used to assess limitations.</p><p>In this study we therefore ask the question whether the growth of heterotrophic microbial communities in tropical soil is limited by available phosphorus or by carbon. We collected soils from three sites along a topographic gradient (plateau, slope, bottom) differing in soil texture, total and available P concentrations from a well-studied, P-poor region in Nouragues, French Guiana. We incubated these soils in the laboratory with C in the form of cellulose, inorganic phosphorus and with a combination of both, and studied microbial growth by measuring the <sup>18</sup>O incorporation from labelled water into microbial DNA. Moreover, we measured microbial respiration and determined microbial biomass C, N (nitrogen) and P.</p><p>Our results demonstrate that, although microbial biomass C and N was similar in soil collected from all three topographic sites, soil respiration rates were significantly higher in soils from the plateau indicating a more active microbial community. Microbial C and N did not respond to cellulose and inorganic P additions, only microbial P increased significantly when P was added in all soils. Although microbial biomass C was not increased, C and P additions stimulated microbial respiration in clay rich plateau soils. In slope soils microbial communities initially only increased respiration activity in response to P additions, however at the end of the incubation also C showed significant differences in respiration activity, with strongest increases when C and P were added in combination. In sandier bottom soils microorganisms responded with increased activity to C addition, but also here respiration showed strongest increases in response to combined carbon and phosphorus additions. We will discuss these findings in relation to the pattern of gross growth rates in these soils and evaluate the stoichiometric limitations of microbial activity and turnover.</p>

Effect of leaching and clay content on carbon and nitrogen mineralisation in maize and pasture soils

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 535 ◽  
Author(s):  
R. L. Parfitt ◽  
G. J. Salt ◽  
S. Saggar
Keyword(s):  
Clay Content ◽  
N Mineralisation ◽  
Incubation Experiment ◽  
Nitrogen Mineralisation ◽  
Total N ◽  
Carbon And Nitrogen ◽  
Maize Sample ◽  
C Mineralisation ◽  
C And N

We conducted a 7-week laboratory incubation experiment to evaluate the effect of leaching on net C and N mineralisation in soils. The soils were collected from adjacent fields of long-term pasture and maize, where each field contained an Inceptisol and an Andisol. The concentration of clay mineral was 200 g/kg halloysite in the Inceptisol and 120 g/kg allophane in the Andisol. Half the samples were leached weekly with 0.002 M CaCl2 at a suction of 20 kPa to remove soluble products, and half were not leached. Carbon mineralisation was determined from CO2-C evolved each week. Net N mineralisation was measured for the leached samples from the NH4-N and NO3-N in the CaCl2 extracts, and for the batch of non-leached samples by extraction in 0.5 M K2SO4. Carbon and net N mineralisation were greater in the soils under pasture than in soils under maize. The proportion of total C mineralised as CO2-C, and of total N mineralised as NH4-N and NO3-N, followed the order Inceptisol-pasture > Inceptisol-maize > Andisol-pasture > Andisol-maize, suggesting that allophane and Al ions reduced net mineralisation. Dissolved organic carbon (DOC) produced during incubation, as a proportion of total C, was greatest for the Inceptisol-maize sample and least for the Andisol-pasture sample. Non-leaching resulted in the accumulation of acids and solutes, and decreased C mineralisation for the Inceptisol samples.

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