scholarly journals Variations in Organic Carbon Content and Dehydrogenases Activity in Post-Agriculture Forest Soils: A Case Study in South-Western Pomerania

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 459
Author(s):  
Katarzyna Wiatrowska ◽  
Jolanta Komisarek ◽  
Janusz Olejnik
Keyword(s):  
Seasonal Variation ◽  
Organic Carbon ◽  
Forest Soils ◽  
Stand Age ◽  
Organic Carbon Content ◽  
Sharp Drop ◽  
The North ◽  
Significant Seasonal Variation ◽  
Significant Difference ◽  
Dehydrogenases Activity

Temperate forest soils of Europe are regarded as an important sink of carbon and thought to have potential to sequester CO2 from atmosphere. However, there are insufficient data not only on organic carbon (OC) content in forest soils and its temporal changes but also on microbiological activity and especially their relationship to carbon turnover. In this study seven research plots were located on afforested land in the north-western part of Poland in Tuczno Forest District (Western Pomerania) in order to examine seasonal variation in OC content and dehydrogenases activity (DHA) during 2012–2016. Based on the studies conducted, statistically significant seasonal variation of the OC content was observed. Higher amounts of OC in the A horizon were observed during spring and autumn seasons and lower in summer. However, no seasonal variation on OC content was observed in the organic horizon (O horizon). Although DHA is thought to exhibit strong seasonal variability, no seasonal variation on DHA was observed. However, a statistically significant difference was observed among studied years (2012–2016), a sharp drop of DHA was noted from spring 2014. Statistical analyses revealed that OC content in soils was a function of forest stand age and progressing acidification of soil. Moreover, OC content in O horizon was negatively correlated with soil moisture and DHA, suggesting that periods with higher microbial activity lead to lower accumulation of carbon in the O horizon. During 2012–2016 only for the O horizon was an increase in OC content was observed.

scholarly journals Soil organic carbon in northern Spain (Galicia, Asturias, Cantabria and País Vasco)

2015 ◽  
Vol 5 ◽  
Author(s):  
Elías Luis Calvo ◽  
Francisco Casás Sabarís ◽  
Juan Manuel Galiñanes Costa ◽  
Natividad Matilla Mosquera ◽  
Felipe Macías Vázquez ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Forest Soils ◽  
Agricultural Soils ◽  
Calcareous Soils ◽  
Mean Annual Precipitation ◽  
Moisture Regime ◽  
Organic Carbon Content ◽  
Northern Spain ◽  
Pais Vasco

The soil organic carbon content was analyzed in more than 7 000 soil samples under different land uses, climates and lithologies from northern Spain (Galicia, Asturias, Cantábria y País Vasco). GIS maps (1:50 000) were made of the % SOC and SOC stocks. The % SOC varies according to land use (higher in forest and scrub soils and lower in agricultural soils) and climate, and there is a highly significant correlation between SOC content and mean annual precipitation. There are significant differences between the soils of Galicia/Western Asturias (GA<sub>w</sub>) and those of the rest of the study area (Central and Eastern Asturias, Cantabria and País Vasco) (A<sub>ce</sub>CV), although these are neighbouring regions. In forest and/or scrub soils with a <em>udic</em> soil moisture regime, in GA<sub>w</sub>, the SOC is usually &gt; 7% and the average stocks 260 t ha<sup> -1</sup> (0-30 cm), and &gt;340 t ha<sup>-1</sup> (0-50 cm) in soils with thick organic matter rich horizons (&gt; 40 cm); these values greatly exceed the average contents observed in forest soils from temperate zones. Under similar conditions of vegetation and climate in soils of A<sub>ce</sub>CV the SOC average is 3% and the mean stocks 90-100 t ha<sup>-1</sup> (0-30 cm). The <em>andic</em> character of acid forest soils in GA<sub>w</sub> and the formation of C-Al,Fe complexes are pointed out as the SOC stabilization mechanism, in contrast to the neutral and calcareous soils that predominate in A<sub>ce</sub>CV, where the main species of OC are easily biodegradable.

Seasonal variation in muscle fatigue in the sartorius muscle of the frog Rana pipiens

1991 ◽  
Vol 69 (6) ◽  
pp. 1712-1715
Author(s):  
Jean Marc Renaud
Keyword(s):  
Seasonal Variation ◽  
Rana Pipiens ◽  
Recovery Period ◽  
Sartorius Muscle ◽  
Tetanic Force ◽  
Fatigue Development ◽  
Significant Seasonal Variation ◽  
Significant Difference ◽  
Force Recovery ◽  
Frog Sartorius

The goal of this study was to determine whether seasonal variation occurs in the rates of fatigue development and force recovery in the frog sartorius muscle. The data were gathered from different experiments performed during a 6-year period (1983–1989). All frog sartorius muscles were stimulated to fatigue with tetanic contractions at the rate of 1/s for 3 min. The decrease in tetanic force after 1.5 and 3 min of stimulation was relatively consistent throughout the year. The only significant difference occurred in the muscles tested in September and October, which were less fatigue resistant than those tested in December. Following fatigue, muscles were stimulated at the rate of one contraction every 100 s, so that the recovery of tetanic force could be followed. A large and significant seasonal variation was observed in the recovery period. Frog sartorius muscles tested between March and July recovered their tetanic force at a faster rate than those tested between August and October. It was shown that the highest capacity to recover force coincides with the time of the year when frogs are the most active.

FURTHER OBSERVATIONS OF THE HORIZONTAL MOVEMENTS OF AURORA

1960 ◽  
Vol 38 (10) ◽  
pp. 1366-1375 ◽  
Author(s):  
J. A. Kim ◽  
B. W. Currie
Keyword(s):  
Magnetic Field ◽  
Seasonal Variation ◽  
Magnetic Field Intensity ◽  
Geomagnetic Latitude ◽  
Auroral Zone ◽  
The North ◽  
Significant Seasonal Variation ◽  
Positive Correlations ◽  
The Magnetic Field ◽  
East West

A previous paper showed that systematic motions of aurora parallel and normal to the geomagnetic meridians could be deduced from successions of all-sky camera photographs. More reliable deductions which are based on a much larger number of observations, including some from a station inside the auroral zone, are reported in this paper. Both southward and northward speeds increase with geomagnetic latitude to the auroral zone where they become constant, or even decrease slightly, before continuing to increase inside the auroral zone. A seasonal variation of north–south speeds does not appear to exist. A diurnal variation of north–south speeds, dependent on geomagnetic latitude, is evident, the speeds decreasing to a minimum during the morning hours to the south of the auroral zone and increasing to a maximum during the same hours to the north of the zone. Large positive correlations exist between north–south speeds and departures of the magnetic field intensity from normal. East–west speeds either decrease or remain constant with increasing geomagnetic latitude. A significant seasonal variation of east–west speeds is not evident. Eastward speeds are at a maximum between 03 and 04 hours L.M.T., and are associated with negative magnetic bays; westward speeds, between 21 and 22 hours L.M.T., and are associated with positive magnetic bays.

Significance and driving forces of dark CO2 fixation for organic carbon inputs in temperate forest soils

2020 ◽  
Author(s):  
Rachael Akinyede ◽  
Martin Taubert ◽  
Marion Schrumpf ◽  
Susan Trumbore ◽  
Kirsten Küsel
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Water Content ◽  
Forest Soils ◽  
Temperate Forest ◽  
Carbon Pool ◽  
Significant Difference ◽  
Temperate Forest Soils ◽  
Organic Carbon Pool

&lt;p&gt;Soils are the largest terrestrial organic carbon pool and one of the largest terrestrial sources of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere. However, not all CO&lt;sub&gt;2&lt;/sub&gt; produced in soils is released into the atmosphere, as dark CO&lt;sub&gt;2&lt;/sub&gt; fixation has been shown to modulate CO&lt;sub&gt;2&lt;/sub&gt; release from soils. Temperate forest soils store up to half of the soil organic carbon pool to 1m depth and are recognized as important components of the global carbon cycle, yet studies on dark CO&lt;sub&gt;2&lt;/sub&gt; fixation in temperate forest soils are scarce. Using a well characterized Cambisol soil plot in the Hainich National Park (temperate forest), Germany, we explore dark CO&lt;sub&gt;2&lt;/sub&gt; fixation with the aim to assess the CO&lt;sub&gt;2&lt;/sub&gt; fixation rates, the influencing biogeochemical parameters, and the contribution of this process to temperate forest soil organic carbon (SOC).&lt;/p&gt;&lt;p&gt;Dark CO&lt;sub&gt;2&lt;/sub&gt; fixation was quantified via the uptake of &lt;sup&gt;13&lt;/sup&gt;C-CO&lt;sub&gt;2&lt;/sub&gt; added to microcosms containing soils sampled from three depths. Under 2% CO&lt;sub&gt;2&lt;/sub&gt; headspace, rates of dark CO&lt;sub&gt;2&lt;/sub&gt; fixation at soil level decreased with depth from 0.86 &amp;#181;g C gdw&lt;sup&gt;-1&lt;/sup&gt;d&lt;sup&gt;-1&lt;/sup&gt; in 0 - 12 cm to 0.05 &amp;#181;g C gdw&lt;sup&gt;-1&lt;/sup&gt;d&lt;sup&gt;-1&lt;/sup&gt; in 70 -100 cm, accounting for up to 1.1% of microbial biomass and up to 0.035% of soil organic carbon. However, as differences in microbial biomass abundance and community profiles with depth were found, no significant difference in the rates across depth was observed at microbial level. This suggests that microbial biomass is an important driver of dark CO&lt;sub&gt;2 &lt;/sub&gt;fixation in soils. Given a global temperate forest area of 6.9 million km&lt;sup&gt;2&lt;/sup&gt; and an average soil bulk density of 1&amp;#160;Mg/m&lt;sup&gt;3 &lt;/sup&gt;dark CO&lt;sub&gt;2&lt;/sub&gt; fixation will potentially account for the gross sequestration of 0.31 - 0.48 GtC/yr to a depth of 1 m. Furthermore, an increase in headspace CO&lt;sub&gt;2&lt;/sub&gt; concentration enhanced CO&lt;sub&gt;2&lt;/sub&gt; fixation rates by up to 3.4-fold under 20% v:v CO&lt;sub&gt;2&lt;/sub&gt; showing that dark CO&lt;sub&gt;2&lt;/sub&gt; fixation can be substantial in soils with higher CO&lt;sub&gt;2&lt;/sub&gt; concentrations.&lt;/p&gt;&lt;p&gt;To validate microbial biomass as a driver of dark CO&lt;sub&gt;2&lt;/sub&gt; fixation in soils, we made comparisons with soil plots from the Schorfheide-Chorin exploratory forest, Germany, a temperate forest characterized by vegetation-specific bacterial community structure, higher sand content and acidic pH gradients. Under these conditions, CO&lt;sub&gt;2&lt;/sub&gt; fixation rates at microbial level were significantly different across depth suggesting that aside microbial biomass, other abiotic factors may influence dark CO&lt;sub&gt;2&lt;/sub&gt; fixation in these soils. Of all the tested abiotic variables, water content was the main explanatory factor for the variations in dark CO&lt;sub&gt;2&lt;/sub&gt; fixation rates in the Schorfheide-chorin soils. Additionally, based on 16S rRNA sequencing, qPCR and PICRUSt2 analysis, only a few putative autotrophic communities were present and displayed vegetation-specific variations indicating an influence of vegetation type and input on the active community.&lt;/p&gt;&lt;p&gt;Our findings highlight microbial biomass, CO&lt;sub&gt;2&lt;/sub&gt; and water content as the main drivers of dark CO&lt;sub&gt;2&lt;/sub&gt; fixation in temperate forest soils with only a small proportion of autotrophs being present, suggesting the potential mediators of this process. We also demonstrate the significance of this process in global temperate forest SOC inputs.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Seasonality in Suicide: A Study of Farming Suicides in England and Wales

Crisis ◽  
2003 ◽  
Vol 24 (3) ◽  
pp. 93-97 ◽  
Author(s):  
Sue Simkin ◽  
Keith Hawton ◽  
Paul S.F. Yip ◽  
Carrie H.K. Yam
Keyword(s):  
Seasonal Variation ◽  
Harmonic Analysis ◽  
Nonparametric Tests ◽  
Occupational Group ◽  
Seasonal Patterns ◽  
Chi Square ◽  
England And Wales ◽  
Significant Seasonal Variation ◽  
Significant Difference ◽  
Chi Square Test

Summary: Seasonality in suicide rates has long been reported. Spring peaks in suicide deaths have been positively correlated with the proportion of the workforce engaged in agriculture. Some studies have indicated that suicides using violent methods are more likely to show seasonality. Recent research has suggested that seasonal patterns have diminished. This study examined deaths in male farmers, an occupational group which might be expected to be more vulnerable to seasonal influences because of the nature of their work and the relatively high proportion of farmers using violent methods for suicide. Data on suicides between 1982 and 1999 by males in England and Wales aged 15 years and over were provided by the Office for National Statistics. Seasonal patterns of suicide in farmers and nonfarmers were examined by nonparametric tests and harmonic analysis. No significant seasonal variation was found for farmers. For nonfarmers, although a chi-square test showed significant variation in monthly distribution, this was not found when a harmonic analysis was applied. There was no significant difference in the variation of violent suicides throughout the year. This study reinforces recent findings that seasonal variation in suicide appears to be diminishing, even in an occupational group where this might be expected.

Effect of biochar on soil respiration in the maize growing season after 5 years of consecutive application

Soil Research ◽  
2014 ◽  
Vol 52 (5) ◽  
pp. 505 ◽  
Author(s):  
Ning Lu ◽  
Xing-Ren Liu ◽  
Zhang-Liu Du ◽  
Yi-Ding Wang ◽  
Qing-Zhong Zhang
Keyword(s):  
Soil Moisture ◽  
Organic Carbon ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Carbon Content ◽  
Growing Season ◽  
Organic Carbon Content ◽  
The North ◽  
Seasonal And Diurnal Variations ◽  
Active Organic Carbon

The effect of biochar on soil respiration (Rs) over one maize-growing season was studied after 5 years of consecutive application in an intensive cropland in the North China Plain. The experiment was carried out in randomly arranged plots with four treatments being evaluated. Three replications were conducted per treatment: a control plot without biochar addition (CK), biochar incorporated at 4.5 t ha–1 year–1 (BC4.5), biochar incorporated at 9.0 t ha–1 year–1 (BC9.0), and incorporated wheat straw (SR). The Rs was determined throughout the growing season of maize in 2012. Soil temperature and moisture were measured simultaneously at 5 cm depth. The results showed that the seasonal and diurnal variations of Rs in the four different treatments were approximately equal, and there was a positive correlation between Rs and soil temperature. The Rs values of treatments BC4.5 and BC9.0 were significantly lower than of SR but not CK. Significant correlations between Rs and soil temperature and soil moisture were observed. Soil temperature had a stronger effect on Rs than did soil moisture, and Rs was more sensitive to soil temperature in the biochar treatments than in the SR and CK treatments. The application of biochar and straw increased the soil active organic carbon content, but an obvious relationship between Rs and the soil active organic carbon content was not found.

scholarly journals Characteristics and Driving Mechanism of Soil Organic Carbon Content in Farmland of Beijing Plain: Implication for the Fate of Engineered Polymers in Soil

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Lanlan Zhang ◽  
Zhen Li ◽  
Shiwen Zhang ◽  
Shasha Xia ◽  
Hongguang Zou ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Organic Fertilizer ◽  
Driving Mechanism ◽  
Organic Carbon Content ◽  
Beijing Plain ◽  
Significant Difference

Soil organic matter (SOM), as a kind of natural polymers, affects the migration and transport of ions and particles in soil system due to its surface characteristics and interaction and then causes significant changes in soil quality such as soil fertility loss and pollutant transfer. It is of great importance to study the temporal and spatial evolution of soil organic matter and its driving mechanism for soil health management. This study aims to fully reveal the evolution characteristics and driving mechanism of soil organic carbon (SOC) in farmland of the Beijing plain based on a six-year site monitoring. According to the research results, there is a significant difference in the overall soil organic content during the 6-year period. The temporal stability of SOC is moderate, and it is inversely proportional to SOC content in terms of spatial distribution. SOC content increases as organic fertilizer input rises, and an extra unit (15 kg·ha−1) of organic fertilizer input leads to an increase of 0.057 g·kg−1 in SOC content. The soil with higher clay content exhibits higher SOC content. The organic carbon content in different soil texture types increases with time, and there is a significant difference between the increases in medium loam and light loam. The grain field plantation system exhibited declining SOC content, while the protected vegetable fields, open vegetable fields, and orchards all showed an increase in SOC content. According to our results, the SOC content of farmland in the plain areas of Beijing is largely dependent on the input of organic carbon if other conditions remain unchanged or exhibit insignificant changes.

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