Soil Basal Respiration Rate Research Articles

Changes in the Carbon Stocks, Microbial and Enzyme Activities of Retic Albic Podzol in Southern Taiga during Postagrogenic Evolution

Soil organic matter largely controls the ecosystem functions of soil and is a source of energy and a nutrient substrate for the soil microbial community as well. The postagrogenic dynamics of organic matter stock (content of organic carbon, Corg; total nitrogen, Ntot; and their ratio, C/N), basic soil properties, and indicators of soil microbial and enzyme activities are analyzed for the chronosequence of Retic Albic Podzol (southern taiga zone, Kostroma oblast, Russia). Different plots of the chronosequence have been withdrawn from agricultural use 11, 16, and 40 years ago. The stratification ratios (SRs) 0–5 : 5–10, 0–10 : 10–20, and 0–10 : 20–30 cm layers for Corg and Ntot contents are also estimated. A statistically significant increase in the contents of Corg and Ntot during the postagrogenic succession is observed in the topsoil layer of the old arable horizon (0–5 and 5–10 cm) as well as an increase in the stratification of their distribution, especially after a closed tree canopy has developed on the former arable land. Postagrogenic succession promotes an increase in the soil basal respiration rate and the content of microbial biomass, the maximum values of which are most often recordable in the soil under a 40-year-old secondary small-leaved forest. During the natural reforestation of the former arable lands, a statistically significant increase in the phosphatase activity is observed within the entire old arable horizon. The peaks of oxidoreductase activity correspond to the stages of succession with the maximum uptake of easily decomposable plant litter. Over the 40 years of postagrogenic succession, all analyzed parameters (except for pHKCl) have increased in a statistically significant manner at all considered depths of the old arable layer, with the highest annual increase in 0–5-cm layer, most enriched for organic matter.

Effects of sheep manure in agricultural soils on the behavior of Folsomia candida and initial growth and development of Avena sativa.

The aim of this study was to evaluate the effects of sheep manure in agricultural soils on the behavior of Folsomia candida and initial growth and development of Avena sativa. For this, an Oxisol was submitted to different doses of sheep manure and was subsequently evaluated for Folsomia candida survival and avoidance behavior through standardized ecotoxicological assays, the initial performance of oats by germination test and the soil basal respiration rate by respirometry methodology. There was an increase in the basal respiration rate of the soil by the application of sheep manure and this was consistent with the increase of the doses. The survival rate and avoidance behavior of springtails were not altered and there was no change in the initial performance of oats, indicating that this manure can be used for organic fertilization of soils with low soil pollutant potential.

Soil remediation approach and bacterial community structure in a long-term contaminated soil by a mining spill (Aznalcóllar, Spain)

The Aznalcóllar accident, which occurred in 1998, spilled 36 × 105 m3 of pyritic sludge and 9 × 105 m3 of acidic water around an area of 43 km2 in the south of Spain. This spill is considered one of the most important metal-mining associated accidents worldwide. In this study, two soil remediation techniques were evaluated: the addition of marble sludge (liming treatment, LS) and the mixing of recovered soils (RC) with contaminated soils (CT) (biopile treatment, BS). Both LS and BS significantly reduce the solubility of Cu, Zn, As, and Pb mainly due to the increase in pH and organic matter content, respectively. Soil basal respiration rate and the seed germination and root elongation bioassay with Lactuca sativa were used to evaluate the toxicity of the potential pollution in the sampled soils. Both bioassays showed that the CT soils exhibited the highest toxicity with a significant reduction in the toxicity of the amended soils (LS and BS). The abundance and structure of microbial communities in the soils were determined by qPCR and Illumina 16S rRNA sequencing, respectively. The absolute abundances of total bacterial and archaeal populations, ammonium oxidising bacteria, and denitrifiers in the CT soils were statistically lower than these found in the other three soils. Similarly, the structure of the bacterial community was highly different in the CT soils. Our results underline the persistence of the detrimental effect of pollutants in CT soils compared to the recuperated (RC) and amended soils (LS and BS). We also highlight the uses of liming or biopile as remediation techniques as satisfactory tools to reduce the impact of heavy metals in the contaminated Aznalcóllar soils.

Microbial responses to doses of cover plant straw in cerrado piauiense oxisol

Carbon and nitrogen from the soil microbial biomass play a significant role in the rotation of C and N, and promote nutrient cycling. Thus, the objective of this study was to evaluate changes in the soil microbial biomass with growing doses of cover plant straw species. The cover plants cultivated in the cerrado biome region were incorporated an Oxisol Ustox. The straw of each cover plant was incorporated at doses of 0; 10; 20 and 30 Mg ha-1. The soil basal respiration was determined by incubating, after 21 days. The microbial biomass carbon and nitrogen were determined by the method the microwave irradiation. The microbial biomass carbon and nitrogen contents in extracts were determined by the wet combustion method and Kjeldahl-N. The metabolic quotient was calculated as the ratio between soil basal respiration rate and microbial biomass C, and the microbial quotient as the ratio between soil microbial biomass C and total carbon of soil. The soil microbial population measured by the attributes of quality responds to the addition of the of grass and legume straws incorporated to the soil; The treatments that cause the greatest stress to the microbial population, at 21 days, mediated by the metabolic quotient, are guandu-anão at a dose of 10 Mg ha-1; Guandu-anão and Guandu fava-larga at 20 Mg ha-1 and Brachiária at a dose of 30 Mg ha-1; The best result regarding microbial attributes of soil quality evaluated was observed with the incorporation of all doses of the straw of Crotalaria-ocroleuca.

Monitoring of fungal root colonisation, arbuscular mycorrhizal fungi diversity and soil microbial processes to assess the success of ecosystem translocation.

To compensate for an airport expansion, including construction on valuable wet meadows of a Natura 2000 system, 1.3 ha of turf, cut into blocks, were transferred to artificial basins in a habitat garden. To evaluate the impact of translocation on this ecosystem, and thus the success of its preservation, we monitored fungal root colonisation of Molinia caerulea, the diagnostic plant species for wet meadows, along with arbuscular mycorrhizal fungi (AMF) species richness and composition in soils and soil microbial processes for three seasons: prior to the transfer (2013) and the two following years (2014-15). We observed few changes in the fungal colonisation of M. caerulea, suggesting that the fungal associations of this species were unaffected. The number of AMF species declined directly after the translocation; however, in 2015, an increased number of species was recorded. There were no differences in AMF species composition, nor did soil basal respiration rate, substrate-induced respiration (SIR), or substrate-active biomass (Cmic) change over the years. Only metabolic coefficient (qCO2) decreased after the transfer. The small number of effects in fungal root colonisation, AMF diversity, and microbial processes following the translocation of the ecosystem prove its success. This can be attributed to the deep turf translocation that kept the relevant microbial communities almost unaffected.

The Successional Trend of Soil Microbial Characteristics after Reclamation Amended with Arsenic Sandstone in the Mu Us Sandy Land, China

Soil microorganisms have played an important role in the formation and evolution of soil ecosystem. Based on sand-binding by arsenic sandstone in Mu Us Sandy Land, to evaluate the effects of land reclamation on soil microbial characteristics, we researched on soil enzyme activities, soil microbial biomass and soil basal respiration rate in different reclamation years. The result showed sandy land reclamation through arsenic sandstone has a positive role in changing the soil texture, accumulation of soil nutrients. Soil catalase activity, dehydrogenase activity, urease activity, alkaline phosphatase activity, invertase activity and arylsulphatase activity increased with the year of reclamation, and significant difference between the different years of reclamation. Soil microbial biomass carbon, soil basal respiration rate and microbial quotient became higher with the increase of the reclamation time, metabolic quotient reduced, that showed sandy land reclamation by blending arsenic sandstone, accelerate succession of the soil ecosystem from low to high range. The results indicate soil enzymes and soil microorganisms play an important role in instructing and predicting the sand soil quality, which provide reference for reasonable sand management measures in Mu Us Sandy Land.

Characteristics of soil nutrients and their relationship with soil microbial properties in Artemisia sacrorum communities in the loess hilly region

Artemisia sacrorum communities with different growth years were selected to analyse soil nutrient characteristics, the variation in soil microbial properties, and their relationships in the loess hilly region. The results showed that with an increase in the number of growth years, soil microbial biomass carbon and nitrogen contents as well as soil phosphatase and urease activities initially decreased and then increased in the A. sacrorum communities. The soil organic carbon, organic nitrogen, and total nitrogen contents as well as soil respiration rate showed an increasing trend and reached a maximum at age (a) 37. The soil available phosphorus content first decreased and then increased, with the lowest level observed at 18 a. By contrast, soil available potassium initially increased and then decreased. Soil microbial biomass carbon had a significant positive correlation with soil organic carbon, total nitrogen and organic nitrogen, while soil respiration had a significant positive correlation with organic nitrogen, soil phosphatase and organic carbon. Soil respiration had a highly significant positive correlation with organic carbon and total nitrogen, while soil phosphatase had a highly significant positive correlation with total nitrogen and organic nitrogen. In the A. sacrorum communities, the soil organic carbon and total nitrogen contents were mainly affected by soil respiration, soil available potassium content was mainly affected by soil urease activity, and soil organic nitrogen content was mainly affected by soil phosphatase activity. These findings indicate that soil basal respiration, urease activity and phosphatase activity were the major microbial factors affecting the characteristics of the soil nutrients in the A. sacrorum communities. In conclusion, the natural restoration process of A. sacrorum communities can enhance soil microbial activity and improve soil quality. Keywords: loess hilly, soil nutrients, soil microbial biomass, soil enzyme activities, soil basal respiration rate DOI: 10.25165/j.ijabe.20181104.3942 Citation: Song L J, Liu W Y, Wu H F, Gao T, Hao W F. Characteristics of soil nutrients and their relationship with soil microbial properties in Artemisia sacrorum communities in the loess hilly region. Int J Agric & Biol Eng, 2018; 11(4): 127-134.

Urbanization Drives SOC Accumulation, Its Temperature Stability and Turnover in Forests, Northeastern China

Global urbanization is a vital process shaping terrestrial ecosystems but its effects on forest soil carbon (C) dynamics are still not well defined. To clarify the effects of urbanization on soil organic carbon (SOC) variation, 306 soil samples were collected and analyzed under two urban–rural gradients, defined according to human disturbance time and ring road development in Changchun, northeast China. Forest SOC showed a linear increase with increasing human disturbance time from year 1900 to 2014 (13.4 g C m−2 year−1), and a similar trend was found for the ring road gradient. Old-city regions had the longest SOC turnover time and it increased significantly with increasing urbanization (p = 0.011). Along both urban–rural gradients SOC stability toward temperature variation increased with increasing urbanization, meaning SOC stability in old-city regions was higher than in new regions. However, none of the urban–rural gradients showed marked changes in soil basal respiration rate. Both Pearson correlation and stepwise regression proved that these urbanization-induced SOC patterns were closely associated with landscape forest (LF) proportion and soil electrical conductivity (EC) changes in urban–rural gradients, but marginally related with tree size and compositional changes. Overall, Changchun urbanization-induced SOC accumulation was 60.6–98.08 thousand tons, accounting for 12.8–20.7% of the total forest C biomass sequestration. Thus, China’s rapid urbanization-induced SOC sequestration, stability and turnover time, should be fully estimated when evaluating terrestrial C balance.

Drivers of temperature sensitivity of decomposition of soil organic matter along a mountain altitudinal gradient in the Western Carpathians

AbstractMountain forest soils contain an important stock of carbon. Their altitudinal gradient can serve as a model for research on the potential risk of increased emission of carbon dioxide to the atmosphere, in a positive feedback of global warming. Using soil samples collected at three elevations (600, 900, and 1200 m a.s.l.) from five separate slopes of the Carpathian Mountains (Poland), we studied the effects of soil physical, chemical and microbial properties controlling the temperature sensitivity (Q10 values) of organic matter decomposition in forest soils. Data of soil basal respiration rate measured in laboratory conditions at six different temperatures (5, 10, 15, 20, 25 and 30 °C) were fitted to a Gaussian function. The modelled soil respiration rates differed between altitudes at temperature exceeding 15 °C, and the respiration rate of soil from 1200 m a.s.l. was higher than in soils from the two lower elevations. Based on the modelled respiration values, we calculated Q10 values in the low (Q10L, 0–10 °C), medium (Q10M, 10–20 °C) and high (Q10H, 20–30 °C) temperature ranges. The Q10 values did not differ between elevations. Q10L and Q10M were negatively related only with the C:N ratio. Temperature sensitivity of decomposition of soil organic matter was not affected by bacterial activity and functional diversity (assessed using Biolog® ECO plates), microbial biomass or community structure (inferred from phospholipid fatty acid assays). Our findings support a kinetics‐based theory of the higher temperature sensitivity of more chemically recalcitrant soil organic matter, put forward by other authors.

Interactive effects of soil temperature and moisture on soil N mineralization in a Stipa krylovii grassland in Inner Mongolia, China

Determining soil N mineralization response to soil temperature and moisture changes is challenging in the field due to complicated effects from other factors. In the laboratory, N mineralization is highly dependent on temperature, moisture and sample size. In this study, a laboratory incubation experiment was carefully designed and conducted under controlled conditions to examine the effects of soil temperature and moisture on soil N mineralization using soil samples obtained from the Stipa krylovii grassland in Inner Mongolia, China. Five temperature (i.e. 9°C, 14°C, 22°C, 30°C and 40°C) and five moisture levels (i.e. 20%, 40%, 60%, 80% and 100% WHC, where WHC is the soil water holding capacity) were included in a full-factorial design. During the 71-day incubation period, microbial biomass carbon (MBC), ammonium nitrogen (NH4 +-N) and nitrate nitrogen (NO3 −-N) were measured approximately every 18 days; soil basal respiration for qCO2 index was measured once every 2 days (once a week near the end of the incubation period). The results showed that the mineral N production and net N mineralization rates were positively correlated with temperature; the strongest correlation was observed for temperatures between 30°C and 40°C. The relationships between moisture levels and both the mineral N production and net N mineralization rates were quadratic. The interaction between soil temperature and moisture was significant on N mineralization, i.e. increasing temperatures (moisture) enhanced the sensitivity of N mineralization to moisture (temperature). Our results also showed a positive correlation between the net nitrification rate and temperature, while the correlation between the NH4 +-N content and temperature was insignificant. The net nitrification rate was negatively correlated with high NH4 +-N contents at 80%–100% WHC, suggesting an active denitrification in moist conditions. Moreover, qCO2 index was positively correlated with temperature, especially at 80% WHC. With a low net nitrification rate and high soil basal respiration rate, it was likely that the denitrification concealed the microbial gross mineralization activity; therefore, active soil N mineralization occurred in 60%–80% WHC conditions.

Measuring basal soil respiration across Europe: Do incubation temperature and incubation period matter?

The European Commission recognises the essential role of soil biology in soil functioning and delivery of ecosystem services, but information is currently lacking evaluate of how these vary across soil and land-use types at a European scale. This study evaluated the measurement of the initial rate of soil basal respiration (BR) as a potential biological indicator of ecosystem service provision. The purpose of this study was to test ISO 16072:2002 (Soil Quality: Laboratory methods for the determining of microbial soil respiration). In the literature a range of pre-incubation temperatures (pre-inc) and experimental incubation temperatures (exp-inc) have been applied when using the ISO method for the establishment of basal respiration. This study evaluated whether the range of temperatures applied during pre- and exp- incubation had a significant effect on the rate of respiration determined when following the protocol established in ISO 16072:2002. The evaluation was carried out on a pedo-climatic gradient spanning ten countries across Europe and covering four biogeographical regions. Three sites were sampled in each country providing a range of soil and land-use parameters. Our results suggest that experimental incubation temperatures of 20°C or above should be used in the application of the methodology ISO 16072:2002 (incubation at 15°C resulted in erratic variation between replicates). However, pre-incubation temperature did not affect the soil basal respiration rate, when following the standard recommendations. The time interval with the best prediction of the initial rate of basal respiration was 6h.

Microbial community structure and functioning along metal pollution gradients

Toxic effects of heavy metals on soil microorganisms have been confirmed in a number of laboratory studies. However, most real-field studies do not allow for strong general conclusions due to a range of problems, such as pseudoreplication and confounding factors, which are almost impossible to control for with the most commonly used polluted versus unpolluted or random sampling designs. Effects of metal contamination on soil microbial community traits were measured along 2 pollution gradients in southern Poland. Employing an experimental regression design, using 2 separate gradients, the authors aimed to control for effects of soil properties and beta-diversity of microbial communities. General microbial activity was measured as soil basal respiration rate and substrate-induced respiration, while microbial functional and structural diversity were analyzed with community-level physiological profiles and phospholipid fatty acid patterns, respectively. Metal concentrations were normalized to their toxicity and integrated in a toxicity index (TI). Microbial activity (basal and substrate-induced respiration) decreased in both gradients with increasing TI. Community-level physiological profiles for fungi correlated positively with TI, but no impact of TI on the community-level physiological profiles of bacteria was observed. The phospholipid fatty acids a:15 and i:17 were positively correlated with TI, whereas 16:1ω9 and 18:2ω9 were negatively correlated with TI. The use of 2 gradients (Olkusz and Miasteczko Śląskie) allowed the authors to reveal a clear effect of pollution on general microbial structure and activities, even though they were not able to control completely for all confounding factors. Soil pH, organic matter content, and nutrient level appeared to be at least as important as TI in determining microbial community structure and activities.

Effect of poultry litter and livestock manure on soil physical and biological indicators in a rice-wheat rotation system

Organic manure is considered as a beneficial fertilizer on soil quality and an excellent alternative resource of chemical fertilizer (CF). However, organic manure from intensive farms may have a negative impact on soil quality because of containing some harmful components, such as heavy metal and antibiotics. The aim of this study was to determine the influence of poultry litter (PL) and livestock manure (LM) from intensive farming on soil physical and biological indicators of soil quality. Results showed that PL and LM amendment increased soil macropore and mesopore volumes and decreased soil micropore volumes. Tensile strength in PL and LM treatment were lower than those in CF, while soil aggregate wet stability index were greater than those in CF. Compared with CF treatment, the microbial biomass C and N contents (+89%, +74%), soil basal respiration rate (+49%) and soil microbial quotient (+45%) in PL and LM treatment were significantly greater. Significant linear correlations were found between soil organic carbon and most soil physical and biological properties (P < 0.01). The results suggested that modern intensive farm manures can be alternate chemical fertilizers as a main fertilizer to improve soil physical and biological indicators in a rice-wheat system.

Avaliação de formulações de glyphosate sobre soja Roundup Ready

Avaliou-se neste trabalho o efeito da aplicação de três marcas comerciais de glyphosate - Roundup Ready® e R. Transorb®, formuladas à base do sal de isopropilamina, e Zapp Qi®, à base do sal potássico - sobre a soja transgênica (variedade CD 219RR), tolerante a esse herbicida . Aos 25 dias após a emergência, quando as plantas apresentavam o segundo trifólio completamente expandido (estádios V2-V3), foram aplicadas formulações do glyphosate na dose de 2.000 g ha-1. Avaliou-se a intoxicação das plantas aos 15 dias após a aplicação do herbicida, o número e massa seca de folíolos, o número de nódulos radiculares e o teor foliar de N, P, K, S, Ca, Mg, Fe, Cu, Zn e Mn, por ocasião do florescimento (59 dias após a emergência - DAE), e o rendimento de grãos ao final do ciclo (127 DAE). A partir de amostras de solo, também coletadas na etapa de florescimento da soja, avaliou-se a taxa de respiração basal do solo, o carbono da biomassa microbiana e quociente metabólico. O Roundup Transorb, formulado à base do sal de isopropilamina, foi mais prejudicial às plantas de soja RG, reduzindo o número de nódulos radiculares e o rendimento de grãos, além de promover maior efeito negativo sobre a microbiota do solo. Roundup Ready, à base do mesmo sal isopropilamina, não deve ser aplicado na soja RG em doses elevadas, haja visto ser capaz de alterar o teor de alguns nutrientes nas folhas da cultura, entre eles N, Ca, Mg, Fe e Cu, além de causar intoxicação nas plantas.

Similar response of labile and resistant soil organic matter pools to changes in temperature

Our understanding of the relationship between the decomposition of soil organic matter (SOM) and soil temperature affects our predictions of the impact of climate change on soil-stored carbon. One current opinion is that the decomposition of soil labile carbon is sensitive to temperature variation whereas resistant components are insensitive. The resistant carbon or organic matter in mineral soil is then assumed to be unresponsive to global warming. But the global pattern and magnitude of the predicted future soil carbon stock will mainly rely on the temperature sensitivity of these resistant carbon pools. To investigate this sensitivity, we have incubated soils under changing temperature. Here we report that SOM decomposition or soil basal respiration rate was significantly affected by changes in SOM components associated with soil depth, sampling method and incubation time. We find, however, that the temperature sensitivity for SOM decomposition was not affected, suggesting that the temperature sensitivity for resistant organic matter pools does not differ significantly from that of labile pools, and that both types of SOM will therefore respond similarly to global warming.

Growth of paper birch ( Betula papyrifera) seedlings increases soil available C and microbial acquisition of soil-nutrients

We compared the flux of energy and nutrients in a mineral forest soil in which paper birch ( Betula papyrifera) seedlings had grown with soils that had been exposed to one of five other tree species over a 22 week growing period. Soil basal respiration rate, metabolic quotient, soil available C ( AC), and the affinity of soil microoganisms for substrate-C left in the soil after harvest all increased significantly, in soils treated with birch root systems. Concentrations of AC in birch-treated soils related to the energy-only limited microbial biomass (MB E), but not the nutritionally limited microbial biomass (MB N). Amounts of rhizosphere activity, described as root-supported MB E per unit root and per unit fine root, were one order of magnitude higher in the birch rhizosphere. Plant uptake of soil-N during the growing period was high while the soil mineral-N pool was low in birch experimental units relative to those of other species, suggesting that birch competed well against soil microorganisms for available mineral-N. Anaerobic N mineralization rates were significantly higher while the MB N-to-MB E ratio, which describes the degree of nutritional limitation of the microbial biomass, was significantly lower in birch-treated soils. Significant negative correlations were found between the MB N-to-MB E ratio and both AC and MB E. These results suggest that high amounts of root labile C compounds in conjunction with rapid mineral-N uptake by birch roots can stimulate microbial communities to acquire nutrients from the native soil.