Organic matter mobilization as affected by soil-solution composition and prevailing clay minerals

2002 ◽  
Vol 33 (13-14) ◽  
pp. 2291-2299 ◽  
Author(s):  
Roberto S. Martínez ◽  
Pablo Zalba ◽  
María B. Villamil ◽  
Norman Peinemann
Keyword(s):  
Organic Matter ◽  
Clay Minerals ◽  
Soil Solution ◽  
Solution Composition

scholarly journals A contribution to the study of the stability of clay minerals from the soil solution composition at different pF values

Clay Minerals ◽  
1979 ◽  
Vol 14 (1) ◽  
pp. 29-37 ◽  
Author(s):  
M. L. Fernandez-Marcos ◽  
F. Macías ◽  
F. Guitián-Ojea
Keyword(s):  
Pore Size ◽  
Clay Minerals ◽  
Soil Solution ◽  
Parent Material ◽  
Solution Composition ◽  
Weathering Processes ◽  
Stability Diagrams ◽  
Silica Concentration ◽  
The Stability ◽  
Insight Into

AbstractThe composition of the soil solution of various horizons of Galician soils was studied to gain insight into the direction of the processes of weathering and neoformation by means of stability diagrams of the clay minerals. The soil solution was extracted by compression at various pF values.The most significant results are as follows. In all the cases studied the mineral in equilibrium with the soil solution is a 1:1 philosilicate. As the pF at which the soil solution is extracted increases, corresponding to smaller pore size, pH increases and silica concentration falls. The stable mineral does not vary significantly between different horizons of the same profile. Each parent material gives rise to a different zonation in the stability diagrams. The predictions of the stability diagrams are in general agreement with the mineralogical data of the clays of the horizons in question.Finally, weathering processes in Galicia are briefly commented on.

Fractions of soil boron: a review

2017 ◽  
Vol 155 (7) ◽  
pp. 1023-1032 ◽  
Author(s):  
R. PADBHUSHAN ◽  
D. KUMAR
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Plant Growth ◽  
Clay Minerals ◽  
Soil Solution ◽  
Soil Ph ◽  
Plant Uptake ◽  
Relative Proportion ◽  
Carbonate Content ◽  
Chemical Forms

SUMMARYKnowledge of different fractions and availability of boron (B) is essential while studying the response of crops to B. Fractionation provides information about the chemistry of B and quantifies its bioavailability. Such information is potentially valuable for predicting bioavailability, B leaching, dynamics, transformation between chemical forms in soils and environmental impacts. Total B (T-B) is quantified into five fractions: readily soluble (Rs-B), specifically adsorbed (Spa-B), oxide bound (Ox-B), organically bound (Org-B) and residual B (Res-B). Of these, Rs-B is the fraction present in soil solution and adsorbed weakly by soil particles, and is most readily available for plant uptake. It accounts for 1–2% of T-B. The second most plant available form is Spa-B; it may be adsorbed onto clay surfaces or associated with organic matter (OM) in soil. The remaining fractions, Ox-B, Org-B and Res-B, are unavailable for plant uptake. The major portion (generally 87·4–99·7%) of T-B is composed of Res-B. Overall, the relative proportion of B in various fractions is in the order of Res B > Org-B > Spa-B > Rs-B > Ox-B. Several factors such as soil pH, soil OM, clay minerals, iron and aluminium oxides and calcium carbonate content may change the relative proportion of B in various fractions and the transformations among different soil B fractions. Some of the B fractions are correlated with others and exhibit responses in terms of plant growth. Non-specifically adsorbed (Nsa-B) and Spa-B are positively and significantly correlated to some sub-fractions of Ox-B, such as B occluded in manganese oxyhydroxides (Moh-B). The most readily available forms of B for plants are Nsa-B, Spa-B and Moh-B.

Soil solution composition and aggregate stability changes caused by long-term farming at four contrasting sites in South Australia

Soil Research ◽  
1996 ◽  
Vol 34 (4) ◽  
pp. 511 ◽  
Author(s):  
R Naidu ◽  
S Mcclure ◽  
NJ Mckenzie ◽  
RW Fitzpatrick
Keyword(s):  
Organic Matter ◽  
Soil Solution ◽  
South Australia ◽  
Aggregate Stability ◽  
Fungal Hypha ◽  
Organic Carbon Content ◽  
Solution Composition ◽  
Horizon Scanning ◽  
Undisturbed Soils

The effect of long-term farming on the cation exchange capacity (CEC), organic carbon content, soil solution composition, and aggregate stability was investigated using contrasting soils from 4 sites in the Mid North of South Australia. Undisturbed and farmed profiles were characterised at each site. Farming led to a 10–50% decrease, approximately, in organic matter and CEC in the surface horizon. Scanning electron microscopic study of the surface and selected subsurface soils revealed poor aggregation, compaction, reduced porosity, and a decrease in aggregate particle size in the farmed surface soils. Intra-aggregate binding in the undisturbed soils appeared to be largely due to fungal hypha, with the roots largely contributing to inter-aggregate binding of soil particles. Electrical conductivity (EC) of soil solutions was generally 2–3 times higher in the undisturbed soils than farmed soils, suggesting increased leaching of ions associated with loss of tree cover. This was also supported by a decrease in the concentrations of mobile ions such as Cl-and Na+ in the farmed soils. The concentrations of Na+ and K+ decreased with farming leading to a decrease in the Gapon selectivity constant for Na–Ca and K–Ca exchange. The changes in soil solution composition together with the decline in organic matter concentrations resulted in increased sensitivity of soils to dispersion.

Particle Size Effects on Concentration of Metals in Lake Erie Bottom Sediments

1984 ◽  
Vol 19 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Alena Mudroch
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Clay Minerals ◽  
Surface Sediment ◽  
Size Effects ◽  
Lake Erie ◽  
Size Fraction ◽  
Mineralogical Composition ◽  
Major Elements ◽  
Sediment Samples

Abstract Surface sediment samples obtained at the offshore and nearshore area of Lake Erie were separated into eight different size fractions ranging from <2 µm to 250 µm. The concentration of major elements (Si, Al, Ca, Mg, K, Na, Fe, Mn and P), metals (Zn, Cu, Cr, Ni, V, Co and Pb) and organic matter was determined together with the mineralogical composition and morphology of the particles in each size fraction. The distribution of the metals in the offshore sediment was bimodal with the majority of the metals divided between the 63 to 250 um size fraction which also contained the highest concentration of organic matter (about 20%) and the <4 µm fraction containing up to 60% of clay minerals. However, the metals in the nearshore sediment were associated mainly with the clay minerals.

Sorption–desorption behavior of PCP on soil organic matter and clay minerals

Chemosphere ◽  
2006 ◽  
Vol 64 (6) ◽  
pp. 972-983 ◽  
Author(s):  
Xunchi Pu ◽  
Teresa J. Cutright
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Clay Minerals

Fractionation of natural algal organic matter and its preservation on the surfaces of clay minerals

2021 ◽  
Vol 213 ◽  
pp. 106235
Author(s):  
Longmeng Wei ◽  
Hongling Bu ◽  
Yanfu Wei ◽  
Honghai Wu ◽  
Gehui Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Clay Minerals ◽  
Algal Organic Matter

scholarly journals Nano-scale texture and porosity of organic matter and clay minerals in organic-rich mudrocks

Fuel ◽  
2014 ◽  
Vol 135 ◽  
pp. 359-373 ◽  
Author(s):  
Utpalendu Kuila ◽  
Douglas K. McCarty ◽  
Arkadiusz Derkowski ◽  
Timothy B. Fischer ◽  
Tomasz Topór ◽  
...  
Keyword(s):  
Organic Matter ◽  
Clay Minerals ◽  
Nano Scale

scholarly journals The impact of four decades of annual nitrogen addition on dissolved organic matter in a boreal forest soil

2013 ◽  
Vol 10 (3) ◽  
pp. 1365-1377 ◽  
Author(s):  
M. O. Rappe-George ◽  
A. I. Gärdenäs ◽  
D. B. Kleja
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Soil Solution ◽  
Mineral Soil ◽  
Solution Concentration ◽  
Oxidative Enzymes ◽  
N Saturation ◽  
N Addition ◽  
Mineral N ◽  
The Impact

Abstract. Addition of mineral nitrogen (N) can alter the concentration and quality of dissolved organic matter (DOM) in forest soils. The aim of this study was to assess the effect of long-term mineral N addition on soil solution concentration of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in Stråsan experimental forest (Norway spruce) in central Sweden. N was added yearly at two levels of intensity and duration: the N1 treatment represented a lower intensity but a longer duration (43 yr) of N addition than the shorter N2 treatment (24 yr). N additions were terminated in the N2 treatment in 1991. The N treatments began in 1967 when the spruce stands were 9 yr old. Soil solution in the forest floor O, and soil mineral B, horizons were sampled during the growing seasons of 1995 and 2009. Tension and non-tension lysimeters were installed in the O horizon (n = 6), and tension lysimeters were installed in the underlying B horizon (n = 4): soil solution was sampled at two-week intervals. Although tree growth and O horizon carbon (C) and N stock increased in treatments N1 and N2, the concentration of DOC in O horizon leachates was similar in both N treatments and control. This suggests an inhibitory direct effect of N addition on O horizon DOC. Elevated DON and nitrate in O horizon leachates in the ongoing N1 treatment indicated a move towards N saturation. In B horizon leachates, the N1 treatment approximately doubled leachate concentrations of DOC and DON. DON returned to control levels, but DOC remained elevated in B horizon leachates in N2 plots nineteen years after termination of N addition. We propose three possible explanations for the increased DOC in mineral soil: (i) the result of decomposition of a larger amount of root litter, either directly producing DOC or (ii) indirectly via priming of old SOM, and/or (iii) a suppression of extracellular oxidative enzymes.

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