A conceptual model for nutrient availability in the mineral soil-root system

1996 ◽  
Vol 76 (2) ◽  
pp. 125-131 ◽  
Author(s):  
George R. Gobran ◽  
Stephen Clegg
Keyword(s):  
Organic Matter ◽  
Conceptual Model ◽  
Norway Spruce ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Base Cations ◽  
Titratable Acidity ◽  
Matter Content ◽  
Bulk Soil ◽  
Soil Fractions

We propose a conceptual model based on our results from rhizospheric studies of a Norway spruce stand growing on a nutrient poor Podzol in Southwest Sweden. We assume that dynamic linkages exist between three soil fractions: bulk soil, rhizosphere (Rhizo) and soil root interface (SRI). The soil fractions were characterized by organic matter content, electrical conductivity, pH, and soluble and exchangeable cations. Analyses showed great differences among the three soil fractions, especially the properties of the SRI. Cation exchange capacity and base saturation were higher in the rhizosphere and SRI than in the bulk soil. We attribute this to accumulation of organic matter (OM) in the rhizosphere and SRI. Moreover, the rhizosphere and SRI fractions had lower pH and higher titratable acidity than the bulk soil. Any possible negative effects of Al to the roots could be offset by accumulated organic matter and base cations (BC). The calcium-aluminum balance followed a consistent trend: bulk < rhizo < SRI. The results suggest that soil around the roots exhibits a different chemical composition than that of the root-free (bulk) soil, indicating more favorable conditions for roots. We suggest that trees growing on nutrient-poor acid soils invest their energy around roots to create a favorable microenvironment for both roots and microorganisms. Our results suggest that existing models which attempt to connect tree growth to soil acidification need modification. Such modification would include horizontal variation (bulk soil, rhizo and SRI) besides the vertical ones normally emphasized. It is possible that the conceptual model may enable a better understanding and description of naturally existing relationships between soil and plants under normal and stressed conditions. Key words: Conceptual model, organic matter, rhizosphere, soil root interface, acidification and growth models, Norway spruce

Soil–air partitioning of volatile organic compounds into soils with high water content

2020 ◽  
Vol 17 (8) ◽  
pp. 545
Author(s):  
Jeonghyeon Ahn ◽  
Guiying Rao ◽  
Mustafa Mamun ◽  
Eric P. Vejerano
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Matter Content ◽  
Exposure Limits ◽  
Case Scenario ◽  
Worst Case ◽  
Water Saturated ◽  
Water Contents

Environmental contextAssessing environmental and human health impacts of chemical spills relies on information about how chemicals move across multiple environments. We measured volatile contaminants in the air above soil saturated with water to provide estimates of air concentrations of selected chemicals released to soil from an oil refinery in Texas during Hurricane Harvey. Estimated concentrations were below recommended exposure limits, even in a worst-case scenario. AbstractThe emission of volatile organic compounds (VOCs) from soil into air is affected by soil moisture dynamics, soil temperature, solar irradiance and carbon availability. The high amount of water in soil can modify its properties, which changes how VOCs interact. We conducted a comprehensive measurement of the soil–air partition coefficient (KSA) of VOCs into water-saturated soil with both low and high water contents for polar, weakly polar and nonpolar VOCs into a mineral soil (S-clay) and soil containing a high amount of organic matter (S-om) under a water-saturated condition. Partitioning of non-polar substituted aromatics (1,2-dichlorobenzene and toluene) was sensitive to the organic matter content in water-saturated soil. 1,2-Dichlorobenzene and toluene had higher affinities to S-om than to S-clay at all investigated water contents because of their strong interaction with the organic matter in soil. KSA decreased with elevated water content only for non-polar substituted aromatic VOCs. Less hydrophobic VOCs (benzene and trichloroethylene) exhibited similar partitioning into both soils by sorbing onto the air-water interface and dissolving in soil water, while the organic matter did not affect partitioning. The weakly polar and polar VOCs (methyl tert-butyl ether and 1-butanol) showed similar partitioning into both soils by dissolving in soil water while sorption to the organic matter was significant only at high soil water contents. KSA of VOCs on soil with high organic matter content correlated strongly with psat and Koa, but not on mineral soil. Estimates of the air concentrations for a subset of VOCs released from one refinery during Hurricane Harvey in 2017 in Harris County, Texas were lower than the recommended exposure limits, even under a worst-case scenario.

Organic matter and mineral distribution in an old-growth Acersaccharum forest near the northern limit of its range

1990 ◽  
Vol 20 (9) ◽  
pp. 1332-1342 ◽  
Author(s):  
I. K. Morrison
Keyword(s):  
Organic Matter ◽  
Forest Floor ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Matter Content ◽  
Parent Material ◽  
Old Growth ◽  
Northern Ontario ◽  
Cu Content ◽  
Base Soil

Two sites, both supporting old-growth Acersaccharum Marsh, dominated forest on rugged topography in central northern Ontario, were compared in terms of organic matter and N, P, K, Ca, Mg, S, Fe, Mn, Zn, and Cu content in the tree- and field-layer phytomass, the forest floor, and the mineral soil. One site was on a shallow, low-base, Precambrian-derived till, and the other was on a till of somewhat higher base status. Gross and net growth of the overstory tree layer were also determined. Total phytomass values for the two stands at the beginning of the study period were 245 000 and 210 000 kg•ha−1, respectively. Gross growth was largely offset by mortality in both stands, producing a rough equilibrium with regard to net increment. Growth before mortality was on the order of 2.4–2.5 m3•ha−1•year−1 in terms of gross total wood volume or 3700–3900 kg•ha−1•year−1 in terms of phytomass, and it was slightly greater in percent terms on the higher base site. In addition to that in the phytomass, organic matter in the forest floor and mineral soil to a depth of 1 m also contributed to the total organic matter content of 638 000–642 000 kg•ha−1 (equivalent to 34 8000–353 000 kg•ha−1 of C) on both sites and was distributed as follows: 29–34% in phytomass, 5% in the forest floor, and 61–66% in mineral soil. The order of abundance of elements in the phytomass was similar on both sites: Ca > N > K > Mg > S > Mn > P > Fe > Zn > Cu, with accumulation in the phytomass in rough proportion to occurrence in the soil. A more base-rich parent material would appear to be the origin of 1452 kg•ha−1 of Ca estimated to be in the phytomass and forest floor on the higher base soil, compared with 1250 kg•ha−1 in the phytomass and forest floor on the lower base soil.

scholarly journals Effects of permanent grass versus tillage on aggregation and organic matter dynamics in a poorly developed vineyard soil

Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 797 ◽  
Author(s):  
Sergio A. Belmonte ◽  
Luisella Celi ◽  
Silvia Stanchi ◽  
Daniel Said-Pullicino ◽  
Ermanno Zanini ◽  
...  
Keyword(s):  
Organic Matter ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Matter Content ◽  
Weakly Bound ◽  
Recovery Capacity ◽  
Organic Matter Dynamics ◽  
Different Seasons ◽  
Organic Matter Fractions

Vineyard soils are typically characterised by poor development, low organic matter content and steep slopes. Consequently, they have a limited capacity for conservation of organic matter that is weakly bound to the mineral soil phase. Under such conditions, establishment of permanent grass may improve soil quality conservation. The aim of this study was to evaluate the effects of permanent grass v. single autumn tillage on soil structure and organic matter dynamics in a hilly vineyard. During the periods 1994–1996 and 2010–2012, soil samples were collected three times per year, in different seasons. Aggregate stability analyses and organic matter fractionation were performed. The effects of grass cover on soil recovery capacity after tillage disturbance were slow to become apparent. Slight increases in aggregate resistance and organic matter contents were visible after 3 years, and the two plots (permanent grass/previously tilled) showed a large decrease of aggregate losses and increase of organic matter only after long-lasting permanent grass. However, even a single tillage produced an immediate decrease in aggregate resistance, while the organic matter content remained unaffected. Organic matter, however, showed marked seasonal dynamics, which involved not only recently added organic matter fractions but also the mineral-associated pool. Tillage altered organic matter dynamics by preventing the addition of new material into the mineral-associated organic fractions and limiting the stabilisation of aggregates.

PHOSPHATASE ACTIVITY OF SOILS AS INFLUENCED BY LIME AND OTHER TREATMENTS

1964 ◽  
Vol 44 (1) ◽  
pp. 137-144 ◽  
Author(s):  
R. L. Halstead
Keyword(s):  
Organic Matter ◽  
Phosphatase Activity ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Clay Content ◽  
Matter Content ◽  
Total Carbon ◽  
Appreciable Effect ◽  
Total Carbon Content ◽  
Mineral Soils

In laboratory incubation experiments liming with Ca(OH)2, CaCO3, or MgCO3 inhibited the phosphatase enzyme activity as measured by determination of phenol or phosphorus released from disodium phenyl phosphate. Chloride and sulphate salts of calcium and magnesium had no appreciable effect on the measured activity. Incubation for 9 months reduced the activity in a group of acid soils but not in a group of nearly neutral soils. Addition of phosphate prior to incubation had no effect on activity in either group.In buffer systems with the pH controlled over the range pH 2.0 to 11.0, activity in samples of an acid mineral soil increased gradually from pH 2.0 to a maximum at about pH 7.0, and then declined rapidly. The occurrence of peaks of optimum activity at pH 5.0 and 9.5 indicated the presence of both acid and alkaline phosphatases in an organic soil.Although there was no significant relationship between phosphatase activity and pH, clay content, nitrogen, and total carbon content of 10 mineral soils, there was a higher activity associated with higher organic matter content in three groups of soils with 3.2, 24.8, and 80.2% organic matter. Initial phosphatase activity of a group of mineral soils was not related to the degree of mineralization of organic soil phosphorus found to occur during an incubation period.

Rhizosphere chemistry in an ammonium sulfate and water manipulated Norway spruce [Picea abies(L.) Karst.] forest

1997 ◽  
Vol 77 (4) ◽  
pp. 525-533 ◽  
Author(s):  
S. Clegg ◽  
G. R. Gobran ◽  
X. Guan
Keyword(s):  
Organic Matter ◽  
Ammonium Sulfate ◽  
Norway Spruce ◽  
Tree Growth ◽  
Water Soluble ◽  
Base Saturation ◽  
Bulk Soil ◽  
Exchange Reactions ◽  
Soil Fractions ◽  
Uptake Of Nutrients

The purpose of this study was to examine how the treatments ammonium sulfate, drought and irrigation changed chemical characteristics of three soil fractions (bulk soil, rhizosphere and soil root interface (SRI)) from E, Bh and Bs horizons of Podzol in a Norway spruce stand in southwestern Sweden. Regardless of the treatment, the properties of the rhizosphere and SRI nearly always differed from the bulk soil due to the high quantity of organic and root material. Irrigation and ammonium sulfate raised water soluble cations and base saturation in the bulk soil. This was possibly due to leaching from the humus and exchange reactions. In the rhizosphere and SRI, irrigation and ammonium sulfate lowered soluble base cations (BC) and base saturation when compared with control; this is attributed to a combination of leaching and high nutrient demand by trees creating a zone of relative depletion. Drought accumulated more organic matter (OM), acidity and cations in the soil fractions suggesting that the lack of water limited transport and uptake of nutrients. Generally, the magnitude of accumulation/depletion of nutrients in the soil fractions reflected the degree of stress which was in turn linked to root uptake of nutrients or to tree growth. Due to the apparent linkage between tree growth, uptake of nutrients and rhizosphere chemistry, we emphasise that soils must be studied at the rhizospheric rather than the bulk soil scale to further understand the effects of environmental stresses. Key words: Ecosystem manipulation, conceptual model, irrigation, organic matter, relative depletion, soil root interface

scholarly journals The Effect of Harvesting Activities on Soil Compaction, Root Damage, and Suckering in Colorado Aspen

1993 ◽  
Vol 8 (2) ◽  
pp. 62-66 ◽  
Author(s):  
Wayne D. Shepperd
Keyword(s):  
Organic Matter ◽  
Soil Profile ◽  
Soil Compaction ◽  
Fine Roots ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Matter Content ◽  
Saturated Soils ◽  
Soil Conditions ◽  
Root Damage

Abstract Logging activities cause significant compaction on skid trails in commercial aspen harvest areas. Bulk density increases have persisted up to 12 yr following harvest. Compaction of the upper 0.2 m of an undisturbed mineral soil profile increased with each succeeding pass of a tractor where later passes contributed less to the total compaction effect. Compaction effects were similar under wet soil conditions. High organic matter content in the upper mineral soil profile may have decreased the magnitude of compaction effects. Root damage can occur without apparent disruption of the soil profile, especially to fine roots and those in saturated soils. West. J. Appl. For. 8(2):62-66.

Cation exchange and buffer potential of Saskatchewan soils estimated from texture, organic matter and pH

1997 ◽  
Vol 77 (4) ◽  
pp. 621-626 ◽  
Author(s):  
D. Curtin ◽  
H. P. W. Rostad
Keyword(s):  
Organic Matter ◽  
Cation Exchange ◽  
Buffer Capacity ◽  
Ph Dependence ◽  
Organic Matter Content ◽  
Titratable Acidity ◽  
Matter Content ◽  
Soil Survey ◽  
Data Set ◽  
Organic C

Cation exchange capacity (CEC) data provide information on important chemical attributes of soil (e.g., ability of soil to retain cations against leaching and to buffer pH). Measurements of CEC are expensive to perform. Further, since CEC is dependent on measurement pH, CEC data are difficult to interpret, especially in the case of soils whose field pH is far removed from measurement pH. We analyzed a large data set (n = 1622), collected in support of soil survey activities in Saskatchewan, to develop a method of estimating CEC as a function of pH and to establish relationships between soil buffer capacity and properties such as texture and organic matter content. A regression equation with organic C and clay as independent variables explained 86% of the variability in CEC measured using BaCl2 buffered at pH 8.2. The CECs (at pH 8.2) of organic matter and clay were estimated at 2130 and 510 mmol (+) kg−1, respectively. About 15% of exchange sites were not accounted for by organic matter and clay and were assumed to reside in the fine silt fraction. The CEC at field pH, i.e., effective CEC (ECEC), was described (R2 = 0.86***) by a function based on the assumption that the ECECs of organic matter and clay increase linearly as pH increases to 8.2, where their values are 2130 and 510 mmol (+) kg−1, respectively. This relationship is especially useful because it enables soil CEC to be estimated at any pH based solely on organic matter and texture. Soil buffer capacity values were obtained by estimating the change in soil ECEC (or titratable acidity) needed to produce a unit change in pH. Buffer strength of clay was low [∼30–50 mmol (±) kg−1 (pH unit)−1]. Our estimates of organic matter buffer capacity [∼400 mmol (±) kg−1 (pH unit)−1] were consistent with published values. The results suggest that prairie soils that are low in organic matter may be susceptible to acidification even if clay content is relatively high. Key words: Buffered CEC, effective CEC, pH dependence of CEC, buffer capacity, titratable acidity

HEAVY METAL SPECIATION IN BOTTOM SEDIMENTS OF THE VYSHNEVOLOTSKY RESERVOIR

2018 ◽  
pp. 46-54
Author(s):  
O. A. Lipatnikova
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Bottom Sediments ◽  
Metal Speciation ◽  
Organic Matter Content ◽  
Water Reservoir ◽  
Matter Content ◽  
Heavy Metal Speciation ◽  
Mobile Forms ◽  
Manganese Hydroxides

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.

Physico-Chemical Properties of Soil Collected from Chandrabhaga River in Kalmeshwar, Nagpur, Maharashtra

2020 ◽  
Vol 07 (02) ◽  
pp. 1-3
Author(s):  
Amita M Watkar ◽  
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Agricultural Land ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Matter Content ◽  
Soil Attributes ◽  
Essential Components ◽  
Agricultural Land Management ◽  
Physical And Chemical

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.

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