The Degradation of the Territories of Snow Polygons

2021 ◽  
Vol 25 (11) ◽  
pp. 30-35
Author(s):  
O.A. Pasko ◽  
A.V. Zakharchenko
Keyword(s):  
Organic Carbon ◽  
Soil Profile ◽  
Vegetation Cover ◽  
Low Temperatures ◽  
Entire Period ◽  
Soil Filtration ◽  
Degree Of Degradation

The assessment of the degree of degradation of the soil and vegetation cover in the territory of storage of snow masses was carried out. It is established that in the soils of the polygons there is a decrease in the reserves of organic carbon, an increase in the power of the abiotic alluvial layer, a reduction in the power of the upper part of the soil profile, washouts and algae are formed. It is determined that the soil filtration coefficients are low. Stagnation of water near the surface and prolonged waterlogging against the background of low temperatures during the entire period of snowmelt were revealed. The soils of all snow polygons are characterized as highly degraded. They have lost their valuable functions for humans and need to be reclaimed.

The Degradation and Bioactivity of Metolachlor in the Soil

Weed Science ◽  
1986 ◽  
Vol 34 (3) ◽  
pp. 479-484 ◽  
Author(s):  
Michael P. Braverman ◽  
Terry L. Lavy ◽  
Clyde J. Barnes
Keyword(s):  
Oryza Sativa ◽  
Organic Carbon ◽  
Incubation Time ◽  
Soil Profile ◽  
Degradation Rate ◽  
Organic Carbon Content ◽  
Silt Loam ◽  
Treated Soil ◽  
Flooded Rice ◽  
Loam Soil

In bioassays, rice (Oryza sativaL.) recovery from metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] injury tended to be slower in flooded rice, but was not significantly different from the recovery rate in a nonflooded rice. In soils treated with 1 ppm (w/w) metolachlor and incubated in constant-temperature chambers, the half-life of metolachlor was shorter at 40 C than at 30 C. The degradation rate of metolachlor was not significantly correlated with declining moisture potentials in the range of −30 to −80 kPa. The CO2evolution from metolachlor-treated soil was negatively correlated with incubation time and positively correlated to declining moisture levels. In a field study, metolachlor, as determined by bioassay, was mobile in a Taloka silt loam soil profile. After being incorporated to 7.5 cm, it became evenly distributed in the top 15 cm of the soil profile within 18 days. Metolachlor adsorption was positively correlated with clay and organic carbon content.

Paddy Soil Profile Distribution of δ13C Subjected to Rice Straw Amendment and Burning

2019 ◽  
Vol 886 ◽  
pp. 3-7 ◽  
Author(s):  
Wutthikrai Kulsawat ◽  
Boonsom Porntepkasemsan ◽  
Phatchada Nochit
Keyword(s):  
Organic Carbon ◽  
Paddy Soil ◽  
Soil Profile ◽  
Management Practices ◽  
Soil Depth ◽  
Animal Health ◽  
Soil Samples ◽  
Residue Management ◽  
Straw Amendment ◽  
Stubble Burning

Paddy residues are the most generous agricultural biomass from the paddy cultivation, Paddy residues practices include crop residue amendment and in-situ burning. It indicated that residue amendment increased the organic carbon and nutrient contents in soil, However, an open residue burning is still a common practice in Thailand despite of strict law enforcements and proper education to farmers about its implications on soil, human and animal health The present study determined how residues management practices: residue amendment and stubble burning, influence the soil organic carbon by determining δ13C in paddy soil profile. The 30 cm depth soil samples from the naturally straw amendment and stubble burning paddy fields were collected in Chiang Khwan district, Roi-et province during 2017. The δ13C values with soil depth showed that residue management practices produce statistical differences in both soils. The δ13C values of soil samples from amendment and burning sites ranged from-23.19‰ to-17.98‰ and-24.79‰ to-19.28‰, respectively. Carbon isotopes differentiate clearly between amendment site (more positive values) and burning site (more negative values). The results from this study were in accordance with literatures which reported that the δ13C distribution in the soil profile can be applied to study in SOC dynamics as a result of different paddy residue management practices (amendment or burning). Further research is needed to confirm the validity of the stable carbon isotope technique in this type of studies.

Effects of agricultural land use change on organic carbon and its labile fractions in the soil profile in an urban agricultural area

2019 ◽  
Vol 30 (15) ◽  
pp. 1875-1885 ◽  
Author(s):  
Youlin Luo ◽  
Qiquan Li ◽  
Jie Shen ◽  
Changquan Wang ◽  
Bing Li ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Soil Profile ◽  
Agricultural Land ◽  
Agricultural Area ◽  
Agricultural Land Use

scholarly journals Short-term legacy effects of feedlot manure amendments on water-extractable organic carbon in a clay loam soil profile

2019 ◽  
Vol 99 (1) ◽  
pp. 36-45 ◽  
Author(s):  
J.J. Miller ◽  
M.L. Owen ◽  
X. Hao ◽  
C.F. Drury ◽  
D.S. Chanasyk
Keyword(s):  
Organic Carbon ◽  
Soil Profile ◽  
Land Application ◽  
Legacy Effects ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Leaching Potential ◽  
Water Extractable Organic Carbon ◽  
Loam Soil ◽  
Water Extractable

Limited research exists on legacy effects of land application of feedlot manure on accumulation, redistribution, and leaching potential of water-extractable organic carbon (WEOC) in soil profiles. We sampled a clay loam soil at six depths (0–1.50 m) 2 yr after the last application (2014) of 17 continuous annual manure applications (since 1998). The amendment treatments were stockpiled (SM) or composted (CM) feedlot manure containing straw (ST) or wood-chip (WD) bedding at three application rates (13, 39, and 77 Mg ha−1dry basis). There was also an unamended control (CON) and inorganic fertilizer (IN) treatment. The soil samples were analyzed for concentrations of WEOC. The total mass or accumulation of WEOC in the soil profile was greater (P ≤ 0.05) by 1.2–3.3 times for the CM-ST-77 treatment than 12 of 14 other treatments, and it was significantly greater for amended than CON or IN treatments. The total WEOC mass was 14%–20% greater for CM-ST than CM-WD, SM-ST, and SM-WD treatments, and it was 16%–22% greater for CM than SM at the 39 and 77 Mg ha−1rates. The 77 Mg ha−1rate of the four manure type-bedding treatments had the significantly greatest (by 37%–527%) concentrations of WEOC at the six depths compared with other treatments, suggesting greater redistribution and leaching potential. Significant manure effects occurred on soil WEOC 2 yr after the manure was last applied following 17 continuous applications, and it indicated an increased risk of leaching potential at the higher application rate.

The chemical and physical stability soil organic carbon in the top 1 m of the soil profile under different land uses in the UK

2020 ◽  
Author(s):  
Dedy Antony ◽  
Jo Clark ◽  
Chris Collins ◽  
Tom Sizmur
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Profile ◽  
Soil Depth ◽  
Physical Stability ◽  
Silty Clay ◽  
Land Uses ◽  
Total N

<p>Soils are the largest terrestrial pool of organic carbon and it is now known that as much as 50% of soil organic carbon (SOC) can be stored below 30 cm. Therefore, knowledge of the mechanisms by which soil organic carbon is stabilised at depth and how land use affects this is important.</p><p>This study aimed to characterise topsoil and subsoil SOC and other soil properties under different land uses to determine the SOC stabilisation mechanisms and the degree to which SOC is vulnerable to decomposition. Samples were collected under three different land uses: arable, grassland and deciduous woodland on a silty-clay loam soil and analysed for TOC, pH, C/N ratio and texture down the first one metre of the soil profile. Soil organic matter (SOM) physical fractionation and the extent of fresh mineral surfaces were also analysed to elucidate SOM stabilisation processes.</p><p>Results showed that soil texture was similar among land uses and tended to become more fine down the soil profile, but pH did not significantly change with soil depth. Total C, total N and C/N ratio decreased down the soil profile and were affected by land use in the order woodland > grassland > arable. SOM fractionation revealed that the free particulate organic matter (fPOM) fraction was significantly greater in both the topsoil and subsoil under woodland than under grassland or arable. The mineral associated OC (MinOC) fraction was proportionally greater in the subsoil compared to topsoil under all land uses: arable > grassland > woodland. Clay, Fe and Mn availability play a significant role (R<sup>2</sup>=0.87) in organic carbon storage in the top 1 m of the soil profile.</p><p>It is evidently clear from the findings that land use change has a significant effect on the dynamics of the SOC pool at depth, related to litter inputs to the system.</p>

scholarly journals Jena Soil Model: a microbial soil organic carbon model integrated with nitrogen and phosphorus processes

2019 ◽  
Author(s):  
Lin Yu ◽  
Bernhard Ahrens ◽  
Thomas Wutzler ◽  
Marion Schrumpf ◽  
Sönke Zaehle
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Profile ◽  
Model Performance ◽  
Nutrient Release ◽  
Co2 Concentration ◽  
Beech Forest ◽  
Forest Site ◽  
Nitrogen And Phosphorus ◽  
Soil Model

Abstract. The plant-soil interactions in a changing environment, such as the response of soil organic matter (SOM) decomposition, nutrient release, and plant uptake to elevated CO2 concentration, is essential to understand the global carbon (C) cycling and predict potential future climate feedbacks. These processes are poorly represented in current terrestrial biosphere models (TBMs) due to the simple linear approach of SOM cycling and the ignorance of variation within the soil profile. While the emerging microbially-explicit soil organic carbon models can better describe C formation and turnover processes, they lack so far a coupling to nutrient cycles. Here we present a new SOM model, JSM (Jena Soil Model), which is microbially-explicit, vertically resolved, and integrated with nitrogen (N) and phosphorus (P) cycle processes. JSM includes a representation of enzyme allocation to different depolymerisation sources based on the microbial adaptation approach, and a representation of nutrient acquisition competition based on the equilibrium chemistry approximation (ECA) approach. We present the model structure and basic features of the model performance against a German beech forest site. The model is capable of reproducing the main SOM stocks, microbial biomass, and their vertical patterns of the soil profile. We further test the model sensitivity to its parameterisation and show that JSM is generally sensitive to the change of microbial stoichiometry and microbial processes.

Whole-soil profile carbon dynamic in response to climate change modulated by vertical carbon transport

2021 ◽  
Author(s):  
Mingming Wang ◽  
Zhongkui Luo
Keyword(s):  
Organic Carbon ◽  
Soil Carbon ◽  
Soil Profile ◽  
Soil Layer ◽  
Vital Role ◽  
Sensitivity Analyses ◽  
Data Sets ◽  
Organic Carbon Content ◽  
Global Pattern ◽  
Carbon Transport

<p>Vertical carbon transport along the soil profile redistributes soil carbon fractions in soil layers, which may have significant consequences on whole-soil profile organic carbon (SOC) dynamics. We developed three varieties of vertically resolved SOC models to simulate SOC dynamics (down to 2 m). The three models took into account mechanisms underpinning the increased persistence of SOC in deeper soil layer depths by explicitly simulating microbial processes and the interactions between old and new carbon pools. Model sensitivity analyses indicated that vertical carbon transport must to be considered; otherwise the profile distribution of SOC stock cannot be captured by the models. The models were further constrained by global data sets of whole-soil profile observations of vertical distribution of SOC stocks and carbon inputs, and then were used to predict the spatial pattern of the depth-specific amount of vertically transported organic carbon (<em>V</em>, g C m<sup>-2</sup> yr<sup>-1</sup>) across the globe. The <em>V</em> showed great variability across the globe as well as across different depths. Precipitation was the most important for influencing the global pattern of <em>V</em>; and soil texture and organic carbon content for the profile pattern. Applying the models across the global, we assessed the response of SOC to 2℃ global warming at the resolution of 1 km. The results suggested that without considering the vertical carbon transport, SOC loss under warming would be underestimated by 10%, particularly in the deeper layers. In wetter areas or areas with stronger soil profile disturbance such as bioturbation and cryoturbation, SOC was more sensitive (i.e., more SOC loss) to climatic warming due to the stronger vertical carbon transport and/or carbon-mixing. Our modelling demonstrates the vital role of vertical carbon transport in controlling whole-soil carbon dynamics, which is a key determinant of whole-soil profile SOC persistence under warming.</p>

Sign in / Sign up

Export Citation Format

Share Document