Effective remediation of diazinon from spent sheep dip wash by disposal on land

2007 ◽  
Vol 47 (1) ◽  
pp. 13 ◽  
Author(s):  
G. W. Levot
Keyword(s):  
Soil Profile ◽  
Soil Depth ◽  
Disposal Site ◽  
Deep Soil ◽  
Limit Of Quantification ◽  
Entire Volume ◽  
South Wales ◽  
Run Off ◽  
Australian Wool ◽  
Pre Treatment

Spent sheep dip wash (about 3500 L) containing 59 mg diazinon/L was evenly distributed onto a 450-m2 grassed, soil-bunded, sloping site near Cumnock in central New South Wales, Australia. The entire volume was contained within the bunded area but surface run-off created ponding in the lowest corner of the site. The mean concentration within the top 7 cm of soil was 2.32 mg/kg a day after application. By day 14, this had dropped to 0.4 mg/kg and by day 56, was below the limit of quantification (0.1 mg/kg). The half-life of diazinon in soil was estimated to be 7 days. Residues in the next 7 cm of soil depth were much lower and were below the limit of quantification in all samples collected at day 28 or later. This suggests that vertical leaching of diazinon within the soil profile did not occur despite more than 95 mm of rain during the trial interval. Throughout the 56-day trial interval, diazinon concentrations in the top 7 cm of soil 3 m downhill of the lowest corner of the dip disposal site were unchanged from background pre-treatment levels. No diazinon was detected in samples at 7–14 cm depth in the soil profile in this area. With neither vertical nor lateral movement of diazinon away from the initial treatment zone, we consider the disposal of spent diazinon sheep dips as described here, to be an acceptable and convenient option for Australian wool producers and dipping contractors. Suitable dip disposal sites should be situated away from sensitive locations in areas that have good grass cover over deep soil and that are contained by an effective bund. Stock and other animals should be excluded from these sensitive locations.

scholarly journals Kinetic Properties of Microbial Exoenzymes Vary With Soil Depth but Have Similar Temperature Sensitivities Through the Soil Profile

2021 ◽  
Vol 12 ◽  
Author(s):  
Ricardo J. Eloy Alves ◽  
Ileana A. Callejas ◽  
Gianna L. Marschmann ◽  
Maria Mooshammer ◽  
Hans W. Singh ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Temperature Sensitivity ◽  
Soil Profile ◽  
Current Knowledge ◽  
Soil Depth ◽  
Microbial Biomass C ◽  
Rate Theory ◽  
Kinetic Properties ◽  
Nutrient Inputs ◽  
Deep Soil

Current knowledge of the mechanisms driving soil organic matter (SOM) turnover and responses to warming is mainly limited to surface soils, although over 50% of global soil carbon is contained in subsoils. Deep soils have different physicochemical properties, nutrient inputs, and microbiomes, which may harbor distinct functional traits and lead to different SOM dynamics and temperature responses. We hypothesized that kinetic and thermal properties of soil exoenzymes, which mediate SOM depolymerization, vary with soil depth, reflecting microbial adaptation to distinct substrate and temperature regimes. We determined the Michaelis-Menten (MM) kinetics of three ubiquitous enzymes involved in carbon (C), nitrogen (N) and phosphorus (P) acquisition at six soil depths down to 90 cm at a temperate forest, and their temperature sensitivity based on Arrhenius/Q10 and Macromolecular Rate Theory (MMRT) models over six temperatures between 4–50°C. Maximal enzyme velocity (Vmax) decreased strongly with depth for all enzymes, both on a dry soil mass and a microbial biomass C basis, whereas their affinities increased, indicating adaptation to lower substrate availability. Surprisingly, microbial biomass-specific catalytic efficiencies also decreased with depth, except for the P-acquiring enzyme, indicating distinct nutrient demands at depth relative to microbial abundance. These results suggested that deep soil microbiomes encode enzymes with intrinsically lower turnover and/or produce less enzymes per cell, reflecting distinct life strategies. The relative kinetics between different enzymes also varied with depth, suggesting an increase in relative P demand with depth, or that phosphatases may be involved in C acquisition. Vmax and catalytic efficiency increased consistently with temperature for all enzymes, leading to overall higher SOM-decomposition potential, but enzyme temperature sensitivity was similar at all depths and between enzymes, based on both Arrhenius/Q10 and MMRT models. In a few cases, however, temperature affected differently the kinetic properties of distinct enzymes at discrete depths, suggesting that it may alter the relative depolymerization of different compounds. We show that soil exoenzyme kinetics may reflect intrinsic traits of microbiomes adapted to distinct soil depths, although their temperature sensitivity is remarkably uniform. These results improve our understanding of critical mechanisms underlying SOM dynamics and responses to changing temperatures through the soil profile.

Nitrogen and sulfur dynamics of contrasting grazed pastures

1999 ◽  
Vol 50 (8) ◽  
pp. 1381 ◽  
Author(s):  
Wen Chen ◽  
Graeme Blair ◽  
Jim Scott ◽  
Rod Lefroy
Keyword(s):  
White Clover ◽  
Soil Profile ◽  
Soil Depth ◽  
Drainage Water ◽  
N Leaching ◽  
15N Recovery ◽  
Mineral N ◽  
Soil Layers ◽  
South Wales ◽  
Ecological Feature

The experimental area was located at the Big Ridge 2 site, CSIRO, Chiswick (30°31′S, 151°39′E), 20 km south of Armidale, New South Wales, Australia. The site was established in 1955. In March 1966, phalaris and white clover were sown and pastures were fertilised annually with superphosphate until 1993. There were 3 pasture treatments, each with 2 replicates: degraded pasture (low phalaris content), phalaris dominant, and phalaris–white clover. Each of 6 experimental plots was divided into 3 strata. Two representative areas 1 m by 0.5 m were selected in each stratum of each treatment. The selected areas were labelled with 34S-enriched (90%) elemental sulfur and 15N-enriched (99%) NH4Cl solution. All plots were grazed continuously by sheep. No effect of pasture type on N leaching was apparent in this experiment. Seasonal variation of total soil mineral N in different soil layers, low 15N recovery down to 60 cm soil depth, and low nitrate-N concentrations in drainage water obtained in this experiment suggest that synchronisation of pasture growth with mineralisation and nitrification, together with ammonium domination of the soil N system, is the key ecological feature in preventing N leaching in this environment. Unlike N, potential S leaching was found with evidence of a large amount of sulfate stored deeper in the soil profile and high S concentrations in drainage water. High KCl-40 extractable S concentration in the top 20 cm soil layers was associated with the long history of superphosphate application. Long-term applications of superphosphate (1967–93), together with an increase in sulfate sorption capacity at lower soil depths, resulted in a large amount of sulfate stored at greater depth. However, retention of the 34S applied in 1995 in the top 10 cm soils suggests that sulfate-S movement down the soil profile is slow.

scholarly journals Soil carbon sequestration by three perennial legume pastures is greater in deeper soil layers than in the surface soil

2016 ◽  
Vol 13 (2) ◽  
pp. 527-534 ◽  
Author(s):  
X.-K. Guan ◽  
N. C. Turner ◽  
L. Song ◽  
Y.-J. Gu ◽  
T.-C. Wang ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Soil Carbon ◽  
Soil Profile ◽  
Soil Depth ◽  
Arable Land ◽  
Growth Period ◽  
Bare Soil ◽  
Soil Carbon Sequestration ◽  
Deep Soil ◽  
Perennial Legume

Abstract. Soil organic carbon (SOC) plays a vital role as both a sink for and source of atmospheric carbon. Revegetation of degraded arable land in China is expected to increase soil carbon sequestration, but the role of perennial legumes on soil carbon stocks in semiarid areas has not been quantified. In this study, we assessed the effect of alfalfa (Medicago sativa L.) and two locally adapted forage legumes, bush clover (Lespedeza davurica S.) and milk vetch (Astragalus adsurgens Pall.) on the SOC concentration and SOC stock accumulated annually over a 2 m soil profile. The results showed that the concentration of SOC in the bare soil decreased slightly over the 7 years, while 7 years of legume growth substantially increased the concentration of SOC over the 0–2.0 m soil depth. Over the 7-year growth period the SOC stocks increased by 24.1, 19.9 and 14.6 Mg C ha−1 under the alfalfa, bush clover and milk vetch stands, respectively, and decreased by 4.2 Mg C ha−1 in the bare soil. The sequestration of SOC in the 1–2 m depth of the soil accounted for 79, 68 and 74 % of the SOC sequestered in the 2 m deep soil profile under alfalfa, bush clover and milk vetch, respectively. Conversion of arable land to perennial legume pasture resulted in a significant increase in SOC, particularly at soil depths below 1 m.

Quantification of deep soil carbon by a wet digestion technique

Soil Research ◽  
2017 ◽  
Vol 55 (1) ◽  
pp. 78 ◽  
Author(s):  
Podjanee Sangmanee ◽  
Bernard Dell ◽  
Richard J. Harper ◽  
David J. Henry
Keyword(s):  
Soil Carbon ◽  
Limit Of Detection ◽  
Soil Depth ◽  
Deep Soil ◽  
Limit Of Quantification ◽  
Wet Digestion ◽  
Digestion Technique ◽  
Carbon Recovery ◽  
Digestion Methods ◽  
Dry Combustion

Two wet digestion methods were evaluated using pure kaolinite as background for quantifying small concentrations of carbon (<0.05% total organic carbon (TOC)) in deep kaolinitic regolith in south-western Australia. The limit of detection and limit of quantification of the Walkley–Black method (0.015 and 0.050% TOC respectively) were approximately five times lower than those of the Heanes method (0.085 and 0.281% TOC respectively). Both methods showed excellent linearity (R2>0.99) using prepared standards (lignin, humic acid, cellulose and chitin mixed with kaolinite and their combinations), in the concentration range 0.008–1.000% TOC. However, the percentage carbon recovery values were underestimated for chitin. The Walkley–Black method (TOCWB, %) was evaluated with 94 calibration and 27 validation deep soil samples (1–35m soil depth) and compared with a dry combustion (Elementar) technique (TOCactual, %). The predictive equation (TOCactual=1.66TOCWB+0.018) (R2=0.91) obtained from the calibration set agreed well with the benchmark dry combustion values (root mean square error=0.017) and is recommended for quantification of deep soil carbon in other kaolinitic regoliths.

scholarly journals Characteristics of soil profile CO<sub>2</sub> concentrations in karst areas and their significance for global carbon cycles and climate change

2019 ◽  
Vol 10 (3) ◽  
pp. 525-538
Author(s):  
Qiao Chen
Keyword(s):  
Soil Ph ◽  
Soil Profile ◽  
Carbon Sink ◽  
Soil Depth ◽  
Global Climate ◽  
Co2 Concentration ◽  
Soil Co2 ◽  
Deep Soil ◽  
Carbon Cycles ◽  
Co2 Concentrations

Abstract. CO2 concentrations of 21 soil profiles were measured in Zhaotong City, Yunnan Province. The varying characteristics of soil profile CO2 concentrations are distinguishable between carbonate and noncarbonate areas. In noncarbonate areas, soil profile CO2 concentrations increase and show significant positive correlations with soil depth. In carbonate areas, however, deep-soil CO2 concentrations decrease and have no significant correlations with soil depth. Soil organic carbon is negatively correlated with soil CO2 concentrations in noncarbonate areas. In carbonate areas, such relationships are not clear. This means that the special geological process in carbonate areas – carbonate corrosion – absorbs part of the deep-soil-profile CO2. Isotope and soil pH data also support such a process. A mathematical model simulating soil profile CO2 concentration was proposed. In noncarbonate areas, the measured and the simulated values are almost equal, while the measured CO2 concentrations of deep soils are less than the simulated in carbonate areas. Such results also indicate the occurrence of carbonate corrosion and the consuming of deep-soil CO2 in carbonate areas. The decreased CO2 concentration was roughly evaluated based on stratigraphic unit and farming activities. Soil pH and the purity of CaCO3 in carbonate bedrock deeply affect the corrosion. The corrosion in carbonate areas decreases deep-soil CO2 greatly (accounting for 5.2 %–66.3 % with average of 36 %) and naturally affects the soil CO2 released into the atmosphere. Knowledge of this process is important for karst carbon cycles and global climate changes and it may be a part of the “missing carbon sink”.

scholarly journals Characteristics of soil profile CO<sub>2</sub> concentrations in karst areas and its significance for global carbon cycles and climate change

2019 ◽  
Author(s):  
Qiao Chen
Keyword(s):  
Soil Ph ◽  
Soil Profile ◽  
Soil Depth ◽  
Global Climate ◽  
Co2 Concentration ◽  
Soil Co2 ◽  
Deep Soil ◽  
Carbon Cycles ◽  
Global Climate Changes ◽  
Co2 Concentrations

Abstract. CO2 concentrations of 21 soil profiles were measured in Zhaotong City, Yunnan Province. The varying characteristics of soil profile CO2 concentration are distinguishable between carbonate and non-carbonate areas. In non-carbonate areas, soil profile CO2 concentrations increase and show significant positive correlations with soil depth. In carbonate areas, however, deep soil CO2 concentrations decrease and have no significant correlations with soil depth. Soil organic carbon is negatively correlated with soil CO2 concentrations in non-carbonate areas. In carbonate areas, such relationships are not clear. It means the special geological process in carbonate areas- carbonate corrosion- absorbs part of the deep soil profile CO2. Isotope and soil pH data also support such process. Mathematical model simulating soil profile CO2 concentration was proposed. In non-carbonate areas, the measured and the simulated values are almost equal, while the measured CO2 concentrations of deep soils are less than the simulated in carbonate areas. Such results also indicate the occurrence of carbonate corrosion and the consuming of deep soil CO2 in carbonate areas. The decreased CO2 concentration was roughly evaluated based on stratigraphic unit and farming activities. Soil pH and the purity of CaCO3 in carbonate bedrock deeply affect the corrosion. The corrosion in carbonate areas decreases deep soil CO2 greatly (accounting for 10–70 %, with average of 36 %), and naturally affects the soil CO2 released into the atmosphere. Knowledge of this process is important for karst carbon cycles and global climate changes, and it may be a potential part of the missing sink.

scholarly journals Comparison of Drivers of Soil Microbial Communities Developed in Karst Ecosystems with Shallow and Deep Soil Depths

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 173
Author(s):  
Huiling Guan ◽  
Jiangwen Fan ◽  
Haiyan Zhang ◽  
Warwick Harris
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Soil Depth ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Deep Soil ◽  
Soil System ◽  
Soil Microbial ◽  
Total Soil ◽  
Karst Ecosystems

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.

Modelling uranium leaching from agricultural soils to groundwater as a criterion for comparison with complementary safety indicators

2006 ◽  
Vol 932 ◽  
Author(s):  
D. Jacques ◽  
J. Šimůnek ◽  
D. Mallants ◽  
M.Th. van Genuchten
Keyword(s):  
Soil Profile ◽  
Reactive Transport ◽  
Transport Model ◽  
Agricultural Soils ◽  
Solid Phase ◽  
Water Flux ◽  
Fertilizer Application ◽  
Mineral Fertilizers ◽  
Deep Soil ◽  
Long Time

ABSTRACTNaturally occurring radionuclides can also end up in soils and groundwater due to human practices, such as application of certain fertilizers in agriculture. Many mineral fertilizers, particularly (super)phosphates, contain small amounts of 238U and 230Th which eventually may be leached from agricultural soils to underlying water resources. Field soils that receive P-fertilizers accumulate U and Th and their daughter nuclides, which eventually may leach to groundwater. Our objective was to numerically assess U migration in soils. Calculations were based on a new reactive transport model, HP1, which accounts for interactions between U and organic matter, phosphate, and carbonate. Solid phase interactions were simulated using a surface complexation module. Furthermore, all geochemical processes were coupled with a model accounting for dynamic changes in the soil water content and the water flux. The capabilities of the code in calculating natural U fluxes to groundwater were illustrated using a semi-synthetic 200-year long time series of climatological data for Belgium. Based on an average fertilizer application, the input of phosphate and uranium in the soil was defined. This paper discusses calculated U distributions in the soil profile as well as calculated U fluxes leached from a 100-cm deep soil profile. The calculated long-term leaching rates originating from fertilization are significantly higher after 200 years than estimated release rates from lowlevel nuclear waste repositories.

scholarly journals Variation in Salinity through the Soil Profile in South Coastal Region of Bangladesh

2018 ◽  
Vol 42 (1) ◽  
pp. 11-23
Author(s):  
Mohammad Asadul Haque
Keyword(s):  
Electrical Conductivity ◽  
Salt Stress ◽  
Soil Profile ◽  
Ph Value ◽  
Soil Depth ◽  
Coastal Region ◽  
Soil Samples ◽  
Salt Accumulation ◽  
Top Soil ◽  
Academy Of Sciences

The spatial variability of salt accumulation through the soil profile was studied at Latachapali union of Kalapara upazila, Patuakhali district, Bangladesh. The soil samples were collected from 30 locations covering six villages of the union: Kuakata, Malapara, Fashipara, Khajura, Mothaopara and Tajepara. Five locations were randomly selected from each village. From each location soil samples were collected from three soil depths at 0-2 cm, 2.1-4 cm and 4.1-6 cm. Electrical conductivity of top 0-2 cm soil depth was 20.49 dS/m, in 2.1-4 cm soil depth was 7.14 dS/m and in 4.1-6 cm soil depth 4.15 dS/m. The study soils were strongly acidic having pH value 4.73, 4.99 and 5.20 in 0-2, 2.1-4 and 4.1-6 cm soil depth, respectively. The highest of 8.8 Na:K ratio was found in 0-2 cm soil depth. The Na:K ratio gradually decreased with the increase of soil depth, having 6.59 in 2.1-4 cm and 5.42. in 4.1-6 cm soil depth. The results clearly reveal that the top soil is very much sensitive to salt stress. Based on the electrical conductivity and Na:K ratio the Fashipara, Kuakata and Tajepara village were found seriously affected by salinity.Journal of Bangladesh Academy of Sciences, Vol. 42, No. 1, 11-23, 2018

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