Predicting clay content on field-moist intact tropical soils using a dried, ground VisNIR library with external parameter orthogonalization

Geoderma ◽  
2015 ◽  
Vol 259-260 ◽  
pp. 196-204 ◽  
Author(s):  
Jason P. Ackerson ◽  
José A.M. Demattê ◽  
Cristine L.S. Morgan
Keyword(s):  
Clay Content ◽  
Tropical Soils ◽  
External Parameter

scholarly journals Barium and Cadmium in Tropical Soils Cropped and Under Native Forest

2021 ◽  
Author(s):  
Iolanda Maria Soares Reis ◽  
Wanderley José de Melo ◽  
Erica Souto Abreu Lima ◽  
Marcos Gervásio Pereira ◽  
Ulisses Sidnei da Conceição Silva ◽  
...  
Keyword(s):  
Multivariate Analyses ◽  
Clay Content ◽  
Tropical Soils ◽  
Native Forest ◽  
Strongly Correlated ◽  
Paulo State ◽  
Potential Availability ◽  
Iron Iron ◽  
Soil Clay ◽  
Soil Clay Content

Abstract Toxic elements pose a high environmental risk because of their long persistence in soil, water, and food chain. This study aimed to estimated potentially available and pseudototal contents of barium (Ba) and cadmium (Cd) in tropical soil under native forest vegetation, sugarcane and maize crops. Soil samples were collected at 0.00–0.20 m depth in different municipalities in São Paulo State, Brazil, and analyzed for fertility, texture, total iron, iron oxides, pseudototal and available Ba and Cd contents. Heavy metals were extracted using different extraction solutions (Mehlich-1, Mehlich-3, and DTPA). Data were subjected to descriptive and multivariate analyses. Correlations between soil clay content, mineralogy, and fertility were also investigated. Of the three extraction solutions tested, Mehlich-3 was the most effective to estimate the potential availability of Ba and Cd. Ba extracted by Mehlich-3 was negatively correlated with goethite, and pseudototal barium was positively correlated with pH CaCl2. Cd extracted by Mehlich-3 was positively correlated with pH CaCl2, and pseudototal cadmium was strongly correlated with iron oxide, clay, and organic matter contents.

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 Sorption and Desorption of Tembotrione and its Metabolite AE 1417268 in Soils with Different Attributes

2019 ◽  
Vol 37 ◽  
Author(s):  
A.T. FARIA ◽  
C.A. FIALHO ◽  
M.F. SOUZA ◽  
N.M. FREITAS ◽  
A.A. SILVA
Keyword(s):  
Organic Matter ◽  
High Performance ◽  
Organic Matter Content ◽  
Clay Content ◽  
Tropical Soils ◽  
Matter Content ◽  
Direct Relation ◽  
Carryover Effects ◽  
Physical Attributes ◽  
Low Levels

ABSTRACT: Tembotrione is registered in Brazil for maize and is used in large areas of the country in each harvest. In recent years, producers have reported carryover effects of this herbicide in succeeding crops to maize. This fact can be attributed to tembotrione recommendations without knowing their interactions with tropical soils colloids. In this study, using high-performance liquid chromatography, it was possible to evaluate the influence of chemical and physical attributes on the sorption and desorption of tembotrione, as well as its metabolite AE 1417268, on seven soils from different regions of Brazil. The coefficients referring to sorption and desorption, as well as the hysteresis index (Kf, 1/n and H) of tembotrione and its metabolite were influenced by pH, clay content and organic matter. In soil samples with low levels of clay and organic matter, values of sorption coefficients were reduced as pH increased. The desorption of tembotrione and its metabolite in all soils were low, mainly in the clayey ones and in soils with higher organic matter content. The sorption of tembotrione and its metabolites varies with the attributes of soil, presenting a direct relation with clay and organic matter contents and an inverse one with soil pH. The desorption of tembotrione and its metabolite decreased with the increase in clay and organic matter contents in the evaluated soils.

scholarly journals Evaluation of the lime requirement of tropical soils in terms of other soil characteristics

1969 ◽  
Vol 36 (2) ◽  
pp. 155-160
Author(s):  
M. A. Lugo López ◽  
F. Abruña ◽  
J. Roldán
Keyword(s):  
Cation Exchange ◽  
Clay Mineral ◽  
Cation Exchange Capacity ◽  
Ph Value ◽  
Organic Matter Content ◽  
Clay Content ◽  
Tropical Soils ◽  
Exchange Capacity ◽  
Matter Content ◽  
Significant Regression

The quantity of limestone required to bring the pH of various acid Puerto Rican soils to 6.5 was investigated and found to vary from several hundred to several thousands pounds per acre. To investigate the relation of clay-mineral type, clay content, cation-exchange capacity, organic-matter content, and pH to lime requirement, these properties were determined for several soils. A highly significant regression of lime requirement on pH was obtained which can be expressed by the equation: Y = 18.39 — 3.196 X, where Y is the lime requirement and X is the pH value. Multiple regressions including other factors did not significantly increase the variability which could be explained on terms of the first regression. Further analysis were made by arranging the data according to the predominant clay mineral. For kaolinitic soils highly significant correlations were obtained between lime requirement and either pH or cation exchange capacity. The regressions were: (a) Y = 15.26 — 2.632 pH, and (b) Y = 3.048 + 0.5774 (cation-exchange capacity), where Y is the lime requirement. A regression of lime requirement on both factors did not significantly increase the variability explained by the second equation. No significant regressions were obtained for beidellitic soils.

scholarly journals Carbon Isotope Dynamics in Some Tropical Soils

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 672-679 ◽  
Author(s):  
Peter Becker-Heidmann ◽  
H-W Scharpenseel
Keyword(s):  
Organic Carbon ◽  
Depth Distribution ◽  
Clay Content ◽  
Distribution Patterns ◽  
Tropical Soils ◽  
Humid Tropics ◽  
Soil Profiles ◽  
Decomposition Of Organic Matter ◽  
C Value ◽  
The Tropics

We determined δ13C and D14C in some agricultural soil profiles of the tropics: Ustalf from the semi-arid tropics (India), a Udult, an Aquoll and an Aquept from the humid tropics (Philippines). We used a thin-layer sampling, resulting in high-resolution depth-distribution patterns of natural 13C and 14C content of organic carbon. Regular plowing or puddling leads to uniform isotope concentrations in the topsoil. Decomposition of organic matter raises the δ13C value, and vertical translocation raises the δ13C value with depth. The change of cultivation from pulses (C3-type metabolism of photosynthesis) to sorghum (C4) results in a decrease of δ13C with depth in the topsoil. Where the clay content in the subsoil is high, δ13C remains constant, due to fixation of organic carbon to clay minerals, and D14C decreases with depth. Below the clay-enriched zone, δ13C declines and D14C rises again, due to a chromatographic-like effect. At some horizon boundaries, inhomogeneities in texture delay percolation locally, thus preventing sorption and causing peak values of D14C.

Estimation of clay content by magnetic susceptibility in tropical soils using linear and nonlinear models

Geoderma ◽  
2021 ◽  
Vol 403 ◽  
pp. 115371
Author(s):  
Vinicius Augusto Filla ◽  
Anderson Prates Coelho ◽  
Adrien Dorvalino Ferroni ◽  
Angélica Santos Rabelo de Souza Bahia ◽  
José Marques Júnior
Keyword(s):  
Magnetic Susceptibility ◽  
Nonlinear Models ◽  
Clay Content ◽  
Tropical Soils ◽  
Linear And Nonlinear

Clay mineralogy effects on sodium fluoride pH of non-allophanic tropical soils

Soil Research ◽  
2004 ◽  
Vol 42 (8) ◽  
pp. 865 ◽  
Author(s):  
M. E. Alves ◽  
A. Lavorenti
Keyword(s):  
Agricultural Soils ◽  
Ammonium Oxalate ◽  
Clay Fraction ◽  
Chemical Properties ◽  
Clay Mineralogy ◽  
Clay Content ◽  
Soil Classification ◽  
Tropical Soils ◽  
Oh Groups ◽  
Soil Weathering

Soil pH measured in 1 m NaF (pHNaF) can be a useful tool for soil classification and to provide better advice on the chemical management of agricultural soils in the tropics. In this study, we verified the effects of clay mineralogy on pHNaF values of non-allophanic soils of São Paulo State, Brazil. Fourteen subsurface soil samples were characterised for chemical properties, clay content, clay mineralogy, and for pHNaF values, which were measured in the whole soil and in both natural and deferrified (dithionite-treated) clay fractions. Regression and correlation analyses showed that both ammonium-oxalate-extractable Al (Alo) and gibbsite contents have positive relationships with both clay and soil pHNaF values. On the other hand, kaolinite is inversely related to the pHNaF measured in the clay and has nonsignificant effect on soil pHNaF. X-ray diffraction patterns of dithionite-treated clays did not show disruption of kaolinite or gibbsite after the treatment with 1 m NaF, suggesting that the displacement of surface OH groups by F– seems to be the main mechanism associated with the pH increase verified in the NaF solution after its contact with the deferrified clay fraction. The smaller influence of hematite on pHNaF seems to be due to its correlation to Alo. Goethite and ammonium-oxalate-extractable Fe (Feo) exert no effect on pHNaF. Finally, the relationships observed in the present study strongly suggest that pHNaF values <10.3 measured in non-allophanic kaolinitic soils with low levels of non-humified organic matter are essentially due to their smaller Alo and gibbsite contents, which agrees with the direct correlation verified between pHNaF and soil weathering degree.

scholarly journals Aluminous clay and pedogenic Fe oxides modulate aggregation and related carbon contents in soils of the humid tropics

2021 ◽  
Author(s):  
Maximilian Kirsten ◽  
Robert Mikutta ◽  
Didas N. Kimaro ◽  
Karl-Heinz Feger ◽  
Karsten Kalbitz
Keyword(s):  
Land Use ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Clay Content ◽  
Tropical Soils ◽  
Positive Feedbacks ◽  
Fe Oxides ◽  
Fe Content ◽  
Wide Range ◽  
High Level

Abstract. Aggregation affects a wide range of physical and biogeochemical soil properties with positive feedbacks on soil carbon storage. For weathered tropical soils, aluminous clays (kaolinite and gibbsite) and pedogenic Fe (oxyhydr)oxides (goethite and hematite; termed Fe oxides) have been suggested as important building units for aggregates. However, as both secondary aluminosilicates and Fe oxides are part of the clay-sized fraction it is hard to separate, how certain mineral phases modulate aggregation, and what consequences this has for organic carbon (OC) persistence after land-use change. We selected topsoils with unique mineralogical compositions in the East Usambara Mountains of Tanzania under forest and cropland. Soils are varying in contents of aluminous clay and Fe oxides. Across the mineralogical combinations, we determined the aggregate size distribution, aggregate stability, OC contents of aggregate size fractions as well as changes in aggregation and OC contents under forest and cropland land use. We found the soil aggregation patterns (high level of macroaggregation and aggregate stability) more similar than different among mineralogical combinations. Yet, an aluminous clay content > 250 g kg−1 in combination with pedogenic Fe contents  4 mm. In contrast, a pedogenic Fe content > 60 g kg−1 in combination with aluminous clay content of

scholarly journals Aluminous clay and pedogenic Fe oxides modulate aggregation and related carbon contents in soils of the humid tropics

SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 363-375
Author(s):  
Maximilian Kirsten ◽  
Robert Mikutta ◽  
Didas N. Kimaro ◽  
Karl-Heinz Feger ◽  
Karsten Kalbitz
Keyword(s):  
Land Use ◽  
Size Distribution ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Clay Content ◽  
Tropical Soils ◽  
Positive Effects ◽  
Fe Oxides ◽  
Aggregate Size Distribution ◽  
Wide Range

Abstract. Aggregation affects a wide range of physical and biogeochemical soil properties with positive effects on soil carbon storage. For weathered tropical soils, aluminous clays (kaolinite and gibbsite) and pedogenic Fe (oxyhydr)oxides (goethite and hematite; termed “Fe oxides”) have been suggested as important building units for aggregates. However, as aluminosilicates, aluminum hydroxides, and Fe oxides are part of the clay-sized fraction it is hard to separate how certain mineral phases modulate aggregation. In addition, it is not known what consequences this will have for organic carbon (OC) persistence after land-use change. We selected topsoils with unique mineralogical compositions in the East Usambara Mountains of Tanzania under forest and cropland land uses, varying in contents of aluminous clay and Fe oxides. Across the mineralogical combinations, we determined the aggregate size distribution, aggregate stability, OC contents of aggregate size fractions, and changes in aggregation and OC contents under forest and cropland land use. Patterns in soil aggregation were rather similar across the different mineralogical combinations (high level of macroaggregation and high aggregate stability). Nevertheless, we found some statistically significant effects of aluminous clay and pedogenic Fe oxides on aggregation and OC storage. An aluminous clay content > 250 g kg−1 in combination with pedogenic Fe contents < 60 g kg−1 significantly promoted the formation of large macroaggregates > 4 mm. In contrast, a pedogenic Fe content > 60 g kg−1 in combination with aluminous clay content of < 250 g kg−1 promoted OC storage and persistence even under agricultural use. The combination with low aluminous clay and high pedogenic Fe contents displayed the highest OC persistence, despite conversion of forest to cropland causing substantial disaggregation. This indicates that aggregation in these tropical soils is modulated by the mineralogical regime, causing moderate but significant differences in aggregate size distribution. Nevertheless, aggregation was little decisive for overall OC persistence in these highly weathered soils, where OC storage is more regulated by direct mineral–organic interactions.

scholarly journals Functional relationships between moisture at several equilibrium points and the clay content of tropical soils

1969 ◽  
Vol 35 (2) ◽  
pp. 66-70
Author(s):  
M. A. Lugo López
Keyword(s):  
Equilibrium Points ◽  
Clay Content ◽  
Field Capacity ◽  
Tropical Soils ◽  
Regression Equations ◽  
Saturation Field ◽  
Functional Relationships ◽  
Humid Region ◽  
Moisture Equivalent ◽  
Very High

The tropical soils of the humid region studied in this investigation have been grouped into two broad categories: (a) Lateritic and (b) nonlateritic. Regression equations are presented which may serve to predict any of the moisture constants considered, namely, maximum saturation, field capacity, moisture equivalent, permanent wilting percentage, and hygroscopic coefficient, on the exclusive basis of the clay content of the soils. Very high correlations were obtained in all cases for lateritic soils. Very high correlations were also found for the nonlateritic soils of the humid Tropics, excepting the values for maximum saturation.

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