scholarly journals Relationships of phosphorus fractions to organic carbon content in surface soils in mature subtropical forests, Dinghushan, China

Soil Research ◽  
2014 ◽  
Vol 52 (1) ◽  
pp. 55 ◽  
Author(s):  
Enqing Hou ◽  
Chengrong Chen ◽  
Dazhi Wen ◽  
Xian Liu
Keyword(s):  
Organic Carbon ◽  
Organic Carbon Content ◽  
P Availability ◽  
Soil Organic C ◽  
Surface Soils ◽  
Organic C ◽  
Subtropical Forests ◽  
Soil P ◽  
P Sorption ◽  
Sorption Index

Exploring the relationship between the accumulation of soil organic carbon (C) and the form and availability of soil phosphorus (P) is important for improved understanding of soil P availability and its regulation of C storage in forest ecosystems. Here, we investigated the relationships among soil organic C, sequentially extracted P fractions and P sorption index in 32 surface soils (0–0.15 m depth) across eight mature subtropical forests (80–400 years) in Dinghushan, China. Results showed that soil organic P (Po) accounted for 40–63% (mean 54%) of soil total P. Soil organic C was significantly positively correlated with both the content and the percentage of soluble inorganic P (Pi), Al-Po and Fe-Po fractions and the content of the Al-Pi fraction. The content of soil total Po increased significantly with soil organic C, whereas the percentage of soil total Po tended to increase with soil organic C only when soil organic C was low (<30 Mg/ha) but was relatively stable when soil organic C was high (≥30 Mg/ha). Moreover, soil organic C was highly correlated with P sorption index. Our results suggest that accumulation of organic C may increase, rather than decrease, the availability of P in surface soil in mature subtropical forests.

Carbon, nitrogen and phosphorus storage in subtropical seagrass meadows: examples from Florida Bay and Shark Bay

2012 ◽  
Vol 63 (11) ◽  
pp. 967 ◽  
Author(s):  
James W. Fourqurean ◽  
Gary A. Kendrick ◽  
Laurel S. Collins ◽  
Randolph M. Chambers ◽  
Mathew A. Vanderklift
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Primary Productivity ◽  
Florida Bay ◽  
Organic Carbon Content ◽  
Nitrogen And Phosphorus ◽  
Organic C ◽  
Shark Bay ◽  
Seagrass Meadows ◽  
C Storage

Seagrass meadows in Florida Bay and Shark Bay contain substantial stores of both organic carbon and nutrients. Soils from both systems are predominantly calcium carbonate, with an average of 82.1% CaCO3 in Florida Bay compared with 71.3% in Shark Bay. Soils from Shark Bay had, on average, 21% higher organic carbon content and 35% higher phosphorus content than Florida Bay. Further, soils from Shark Bay had lower mean dry bulk density (0.78 ± 0.01 g mL–1) than those from Florida Bay (0.84 ± 0.02 mg mL–1). The most hypersaline regions of both bays had higher organic carbon content in surficial soils. Profiles of organic carbon and phosphorus from Florida Bay indicate that this system has experienced an increase in P delivery and primary productivity over the last century; in contrast, decreasing organic carbon and phosphorus with depth in the soil profiles in Shark Bay point to a decrease in phosphorus delivery and primary productivity over the last 1000 y. The total ecosystem stocks of stored organic C in Florida Bay averages 163.5 MgCorg ha–1, lower than the average of 243.0 MgCorg ha–1 for Shark Bay; but these values place Shark and Florida Bays among the global hotspots for organic C storage in coastal ecosystems.

Sorption of Metribuzin and Metolachlor in Alaskan Subarctic Agricultural Soils

Weed Science ◽  
1992 ◽  
Vol 40 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Jeff S. Graham ◽  
Jeffery S. Conn
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Soil Type ◽  
Surface Soil ◽  
Agricultural Soils ◽  
Freundlich Isotherm ◽  
Organic Carbon Content ◽  
Surface Soils ◽  
Adsorption And Desorption ◽  
Equilibration Temperature

Adsorption and desorption of metribuzin and metolachlor were studied for 0- to 15- and 30- to 45-cm soil depths and at 5 and 28 C temperatures for two subarctic Alaskan agricultural soils. Surface soils had five to eight times the organic carbon content of deeper soils and had lower Freundlich isotherm slopes (1/n) for both herbicides. Surface soil Freundlich coefficients (Kf) were affected by both soil type and equilibration temperature, with soil type accounting for greater than 80% of the variation in Kf. Surface soil mean Kfvalues ranged from 1.5 to 2.4 for metribuzin and 4.4 to 9.2 for metolachlor. For soils from the 30- to 45-cm depth, neither soil type nor temperature affected Kf. Isotherm slopes for desorption were less than adsorption, indicating hysteresis. Regressions between desorption Kfand maximum herbicide adsorbed prior to desorption were highly significant with coefficients of determination (r2) between 0.50 and 0.99.

Differences in sorption behaviour of carbaryl and phosalone in soils from Australia, Pakistan, and the United Kingdom

Soil Research ◽  
2001 ◽  
Vol 39 (4) ◽  
pp. 893 ◽  
Author(s):  
R. Ahmad ◽  
R. S. Kookana ◽  
A. M. Alston ◽  
R. H. Bromilow
Keyword(s):  
United Kingdom ◽  
Organic Carbon ◽  
Carbon Content ◽  
Organic Carbon Content ◽  
Local Conditions ◽  
Sorption Behaviour ◽  
Organic C ◽  
The United Kingdom ◽  
D Values ◽  
The Uk

Sorption of 2 nonionic pesticides, carbaryl (1-naphthyl methylcarbamate) and phosalone (S-6-chloro-2,3-dihydro-2-oxobenzoxazol-3-ylmethyl O,O-diethyl phosphorodithioate), was investigated for 48 soils from Australia, Pakistan, and the United Kingdom. A wide variation in sorption affinities of the soils to carbaryl and phosalone was observed. The sorption coefficient (K d) values for carbaryl ranged from 0.19 to 23.0 L/kg in Australian soils, from 0.99 to 59.7 L/kg in Pakistani soils, and from 1.09 to 23.0 L/kg in the UK soils. The K d values for phosalone ranged from 4.8 to 443 L/kg in Australian soils, from 15.5 to 1182 L/kg in Pakistani soils, and from 18.1 to 205 L/kg in the UK soils. To eliminate the effect of variation in organic carbon content among the soils, the K d values were normalised to the fraction of soil organic carbon (K oc ). However, K oc values for both pesticides varied by about an order of magnitude across the soils, decreasing in the following order: Pakistani > Australian > UK soils. Correlation between K d and organic carbon content of the soils was poor (r 2 = 0.44 and 0.46). The particulate organic C (53 µm–2 mm) was only slightly better correlated with K d than the total organic C in the <2 mm fraction of the soils. Thus soil organic C content alone is not a good predictor of sorption even for nonionic pesticides such as carbaryl and phosalone. Caution is needed during extrapolation of overseas data to predict sorption under local conditions.

Phosphorus sorption - desorption by purple soils of China in relation to their properties

Soil Research ◽  
2007 ◽  
Vol 45 (3) ◽  
pp. 182 ◽  
Author(s):  
M. Li ◽  
Y. L. Hou ◽  
B. Zhu
Keyword(s):  
Binding Energy ◽  
Single Point ◽  
Phosphorus Sorption ◽  
Soil P ◽  
P Sorption ◽  
Desorption Curve ◽  
Degree Of P Saturation ◽  
Soil Test P ◽  
Sorption Index ◽  
Water Eutrophication

The understanding of phosphorus (P) sorption and desorption by soil is important for better managing soil P source and relieving water eutrophication. In this study, sorption–desorption behaviour of P was investigated in purple soils, collected from 3 kinds of purple parent materials with different kinds of land cover, in the upper reaches of Yangtze River, China, using a batch equilibrium technique. Results showed that most of the farmed purple soils had P sorption capacity (PSC) values ranging from 476 to 685 mg P/kg, while higher PSC values were observed in the soils from forestland and paddy field. A single-point P sorption index (PSI) was found to be significantly correlated with PSC (R2 = 0.94, P < 0.001), suggesting its use in estimating PSC across different types of purple soils. The PSC of purple soils was positively and strongly related to the contents of amorphous Fe and Al oxides (r = 0.73, P < 0.001), clay (r = 0.55, P < 0.01), and organic matter (r = 0.50, P < 0.05). Furthermore, the constant relating to binding strength was positively correlated with the content of amorphous Fe and Al oxides (r = 0.66, P < 0.01), but negatively correlated with labile Ca (r = –0.43, P < 0.05) and soil pH (r = –0.53, P < 0.01). Some acidic purple soils with high binding energy featured a power desorption curve, suggesting that P release risk can be accelerated once the P sorbed exceeds a certain threshold. Other soils with low binding energy demonstrated a linear desorption curve. The P desorption percentage was significantly correlated with soil test P (r = 0.78, P < 0.01) and the degree of P saturation (r = 0.82, P < 0.01), but negatively correlated with PSC (r = –0.66, P < 0.01).

scholarly journals Phosphorus sorption on tropical soils with relevance to Earth system model needs

Soil Research ◽  
2019 ◽  
Vol 57 (1) ◽  
pp. 17 ◽  
Author(s):  
Julia Brenner ◽  
Wesley Porter ◽  
Jana R. Phillips ◽  
Joanne Childs ◽  
Xiaojuan Yang ◽  
...  
Keyword(s):  
Sorption Isotherms ◽  
Clay Content ◽  
Tropical Soils ◽  
Soil Characteristics ◽  
P Availability ◽  
Earth System ◽  
Phosphorus Sorption ◽  
Soil P ◽  
P Sorption ◽  
Earth System Models

Phosphorus (P) availability critically limits the productivity of tropical forests growing on highly weathered, low-P soils. Although efforts to incorporate P into Earth system models (ESMs) provide an opportunity to better estimate tropical forest response to climate change, P sorption dynamics and controls on soil P availability are not well constrained. Here, we measured P and dissolved organic carbon (DOC) sorption isotherms on 23 soils from tropical Oxisol, Ultisol, Inceptisol, Andisol, and Aridisol soils using P concentrations from 10 to 500mg P L−1, and DOC concentrations from 10 to 100mg DOC L−1. Isotherms were fit to the Langmuir equation and parameters were related to soil characteristics. Maximum P sorption capacity (Qmax) was significantly correlated with clay content (ρ=0.658) and aluminium (Al)- or iron (Fe)-oxide concentrations (ρ=0.470 and 0.461 respectively), and the DOC Qmax was correlated with Fe oxides (ρ=0.491). Readily available soil characteristics could eventually be used to estimate Qmax values. Analysis of literature values demonstrated that the maximum initial P concentration added to soils had a significant impact on the resultant Qmax, suggesting that an insufficiently low initial P range could underestimate Qmax. This study improves methods for measuring P Qmax and estimating Qmax in the absence of isotherm analyses and provides key data for use in ESMs.

scholarly journals Contribution of soil organic carbon and C3 sugar to the total CO2 efflux using 13C abundance

2011 ◽  
Vol 52 (No. 5) ◽  
pp. 193-198 ◽  
Author(s):  
R. Koçyiğit
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Isotope Ratio ◽  
Soil Management ◽  
Soil Organic C ◽  
Short Term ◽  
Organic C ◽  
Relative Contribution ◽  
Sugar Addition ◽  
Proportional Contribution

The differences in C isotope ratio of C<sub>3</sub> and C<sub>4</sub> plant species have been used to determine relative contributions of carbon (C) sources to total CO<sub>2</sub> efflux. The objective of this study was to estimate the contribution of soil organic C and C<sub>3</sub> sugar to total CO<sub>2</sub> of corn and wheat monocultures during a short-term incubation. Control soils and soils amended with sugar were incubated at 25&deg;C for 48 hours and total CO<sub>2</sub> concentration and &delta;<sup>13</sup>C values of evolved CO<sub>2</sub> were measured. The proportional contribution of C sources on CO<sub>2</sub> efflux was determined by using isotopic composition of soil organic C and C<sub>3</sub> sugar. &delta;<sup>13</sup>C values of soils are highly affected by the type of vegetation and the soil management. The C<sub>3</sub> sugar addition in soils double the CO<sub>2</sub> efflux in the corn soil, but it did not affect CO<sub>2</sub> efflux in the wheat soil. This indicated a larger turnover of microbial biomass in the corn soil. The greatest significant (P &lt; 0.05) difference in &delta;<sup>13</sup>C values between the control and sugar added soils occurred at 12 hours in the corn soil (11.2&permil;) and at 24 hours in the wheat soil (9.4&permil;). The estimated relative contribution of sugar to CO<sub>2</sub>efflux was stronger at 12 hours incubation in the corn soil.

scholarly journals Laboratory study of retention and release of weak acid herbicide MCPA by soils and sediments and leaching potential of MCPA

2011 ◽  
Vol 52 (No. 12) ◽  
pp. 550-558 ◽  
Author(s):  
E. Hiller ◽  
M. Khun ◽  
L. Zemanová ◽  
Ľ. Jurkovič ◽  
M. Bartaľ
Keyword(s):  
Aqueous Solution ◽  
Organic Carbon ◽  
Carbon Content ◽  
River Sediments ◽  
Weak Acid ◽  
Organic Carbon Content ◽  
Surface Soils ◽  
Leaching Potential ◽  
Soil Sediment ◽  
Soils And Sediments

MCPA sorption and desorption in five surface soils (denoted as A1-5), three bottom sediments (S1-3), two river sediments (L1-2) and one subsurface soil (SS) at two initial concentrations in aqueous solution &ndash; C<sub>0</sub> = 0.5 and 10&nbsp;mg/l were studied. No significant effect of the initial concentration on MCPA equilibrium distribution between soil/sediment and aqueous solution was observed. The difference between distribution coefficient K<sub>D</sub> at C<sub>0</sub> = 0.5&nbsp;mg/l and K<sub>D</sub> at C<sub>0</sub> = 10 mg/l was found only in the case of one bottom sediment (S2). A simple regression analysis between K<sub>D</sub> at C<sub>0</sub> = 0.5 and 10 mg/l and soil/sediment properties indicated that the most important property which determined the variation in MCPA sorption is organic carbon (r = 0.886*** and r = 0.926***, respectively). Similarly, desorption of MCPA was inversely proportional to organic carbon content of the soils and sediments used (r = &ndash;0.862* and r = &ndash;0.842**). These observations showed that MCPA sorption and desorption in soils and sediments were primarily controlled by organic components of the geosorbents used. Overall, the percentage of MCPA sorption in soils and sediments was low (P<sub>sorp</sub> &asymp; 3&ndash;53%; K<sub>D</sub> = 0.077&ndash;2.827 l/kg) and the percentage of MCPA desorbed was relatively high (P<sub>des</sub> &asymp; 11&ndash;70%), especially in the soils and sediments with lower organic carbon content. The experimental results and calculated values of groundwater ubiquity score GUS and relative leaching potential index RLPI imply that MCPA is very mobile in all the surface soils and has a potential to contaminate groundwater.

Reflectance characteristics of southern Alberta soils

1992 ◽  
Vol 72 (4) ◽  
pp. 611-615 ◽  
Author(s):  
D. J. Major ◽  
H. H. Janzen ◽  
S. M. McGinn ◽  
B. M. Olson
Keyword(s):  
Remote Sensing ◽  
Organic Carbon ◽  
Crop Productivity ◽  
Carbonate Content ◽  
Organic Carbon Content ◽  
Strongly Correlated ◽  
Organic C ◽  
Southern Alberta ◽  
Positive Linear Correlation ◽  
Soil Reflectance

The reliability of reflectivity measurements for the remote sensing of crop productivity may be compromised by possible confounding effects of variation in soil color. An experiment was conducted to determine the influence of selected soil characteristics on reflectance in a broad range of soils typical of those found in southern Alberta. The reflectance of ground (< 2 mm) subsamples of 36 soils previously relocated to a common field site at Lethbridge Alberta was measured indoors with an artificial light source and a 60° field of view. Reflectance was measured between 400 and 1100 nm at 5-nm intervals. Reflectance of ground soils was strongly correlated to that of measurements in the field (r2 = 0.99), though values from the former were consistently higher. Soil reflectance declined with increasing organic carbon content in a quadratic relationship. Furthermore, there was a positive linear correlation between reflectance and soil carbonate content. Variation in organic C and carbonate accounted for 60% of the variability in reflectance among soils, based on multiple regression analysis. These findings confirm that soil carbon exerts a significant effect on reflectance and that reliable estimates of crop productivity by remote sensing requires correction for variable soil reflectance. Key words: Remote sensing, visible infrared reflectance, organic carbon

Distribution of dioxins in surface soils and river-mouth sediments and their relevance to watershed properties

2006 ◽  
Vol 53 (2) ◽  
pp. 11-21 ◽  
Author(s):  
M. Kanematsu ◽  
Y. Shimizu ◽  
K. Sato ◽  
S. Kim ◽  
T. Suzuki ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
River Sediments ◽  
River Mouth ◽  
Organic Carbon Content ◽  
Surface Soils ◽  
The Difference ◽  
To Come ◽  
Ado River ◽  
Calux Assay

The dioxins toxic equivalent (TEQ) concentration in surface soils, river sediments and river-mouth sediments was measured by the CALUX assay in the Yasu and Ado River basins around Lake Biwa, Japan. In order to examine the distribution of dioxins in each watershed, we evaluated and compared the correlation between the dioxins TEQ concentration and the solid characteristics (i.e. organic carbon content and particle size distribution) of all samples. In both basins, the dioxins TEQ concentration in forest soil correspondingly showed a very good linear relationship to organic carbon content. On the other hand, the dioxins TEQ concentration in paddy field was significantly high, although organic carbon content was relatively low. Generally, the smaller particles have the higher dioxins TEQ concentrations in surface soils, and river sediments were composed of very coarse particles and had relatively low dioxins TEQ concentration. Therefore, we expected high dioxins TEQ concentration in river-mouth sediment, which was, however, not the case. Although the dioxins TEQ concentration in river-mouth sediments is low, the degree of dioxins pollution was different in each basin. The difference was considered to come from the difference of watershed properties including land use, river-slope, dam construction as well as the surface soil pollution.

Influence of Grasscover in Restoring the Properties of Eroded Soils of Umudike, Southeastern, Nigeria

2020 ◽  
Vol 3 (1) ◽  
pp. 33-50
Author(s):  
Onwuchekwa Ojimgba
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Content ◽  
Chemical Properties ◽  
Bare Soil ◽  
Paspalum Notatum ◽  
Panicum Maximum ◽  
Organic Carbon Content ◽  
Research Attention ◽  
Organic C

The influence of grasscover in restoring the eroded soils was carried out in Umudike, Southestern Nigeria. The use of grass has attracted considerable research attention with respect to forage production and erosion control. Little information is available on the influence of this grasscover management on soil physical and chemical properties. Four different grasses namely: Paspalum notatum(PN), Panicum maximum(PM), Axonopus compressus(AC) and Vetiver grass(VG)- Vetiveria zizanioid/es) were used in this study and their influence on eroded soil tested in two locations. This study has shown that the soils planted with the grasses gave significantly (p<0.05) higher results of the physical and some chemical properties than their adjacent open bare soil. In all the parameters considered in this study, the values obtained in soils under Paspalum notatum was higher than those obtained in PM, AC, VG and their adjacent bare soils(BS). The soils under PN had generally lower bulk density, higher total porosity and hydraulic conductivity than other grasses and adjacent open bare soil in both locations. The soil under PN proved best, outperforming PM, VG,and AC in stabilizing soil aggregates. Planting of PN on eroded soil significantly (p<0.05) increased the mean weight diameter from 0.77mm (BSPN1) to 1.31mm (PN1) and 0.82mm (BSPN2) to 1.48mm (PN2) for Locations 1 and 2, respectively. The relative improvement in Location 1 was in the order : PN1>AC1=VG1>PM1>BSVG1=BSPN1>BSAC1=BSPM1. Also, soils under PN had significantly higher values of pH, organic C and organic matter, total nitrogen and available P more than other grasses and their adjacent open soils. The magnitude of increase in Location 1 was in the order : PN1>AC1>PM1=VG1>BSVG1=BSPN1=BSAC1>BSPM1. Location 2 also increased in the same trend. The organic carbon content of PN increased from 0.73%(BSPN1) to 2.89%(PN1) and 0.88%(BSPN2) to 2.91%(PN2) in Locations 1 and 2, respectively. Also, the organic matter content of the soil increased in the same trend as organic carbon content.

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