Contribution of the chemical and mineralogical properties of sandy-loam tropical soils to the cation exchange capacity

Abstract

Soils originating from the Caiuá sandstone formation have low soil organic matter (SOM), clay content, and cation exchange capacity (CEC). The predominance of one component over the other might decisively influence the CEC of these soils. Particle size distribution and selective dissolution procedures associated to a suit of methods to determine the exchangeable capacity properties might clarify the relative importance of each soil component. The objective of this work was to evaluate the contribution of the different components of the solid fraction and their intrinsic attributes to the CEC of sandy-loam soils and their relation to the total organic carbon (TOC), C:N ratio, and soil mineralogy. For this purpose, 34 soil samples were selected from the Caiuá sandstone formation with significant variation in the carbon content. Clay size fraction was characterized by X-ray diffraction, routine chemical analysis, and total specific surface area-SSA T using EGME, before and after the removal of SOM with sodium hypochlorite solution. Different values of CEC and effective cation exchange capacity (ECEC) were determined following standard procedures. The soils presented high sand content (82.9 ± 5.9 %) and the mineralogy of the clay fraction is dominated by kaolinite (>80 %) with the presence of illite, 2:1 clay minerals, and small amounts of iron and aluminum oxides. The CEC and ECEC values at pH 7.0 and ~5.6, respectively due to the SOM are 408.6 and 148.7 cmol c kg-1 of carbon, respectively. The SOM was responsible for 32 to 84 % (average 52 %) and 24 to 67 % (average of 46 %) of the CEC and ECEC of the soils, respectively. The CEC and ECEC of the inorganic fraction are 2.32 and 0.78 cmol c kg-1 of minerals, respectively. The CEC of the clay fraction increased with the TOC but decreased exponentially with the clay content. The total carbon content increased linearly with the C/N ratio. The SSA T showed a significant (p<0.05) and positive correlation with the TOC and with the CEC of the soils.

Interrelationships among mountain relief, surface organic layer, soil organic carbon, and its mineral association under subarctic forest tundra

“…In our study, Al d was the best predictor of SOC concentration among dithionite and oxalate Fe and Al extractions. This instance adds to several other cases where Al showed a higher affinity for SOC than did Fe 77 – 79 or it was, as Al d, associated with more favorable weathering conditions 80 , 81 . Given these findings, we deduced that the higher Al d content in Bucharama resulted from faster soil weathering on steeper slopes and under a thinner SOL.…”

Nitrogen Fertilizers Technologies for Corn in Two Yield Environments in South Brazil

“…Thus, the parent material of the clayey soil located in northern Paraná state is basalt, an igneous rock rich in micronutrients such as Fe and Mn, because these elements have the same geochemical formation environments [ 86 ]. In contrast, the sandy soil located in the northwestern part of the Paraná state originates from sandstones of the Caiuá Formation, a sedimentary rock whose main constituent mineral is quartz [ 87 ]. Consequently, higher levels of Fe and Mn are naturally available in clayey soil, favoring greater absorption and concentration of these nutrients in corn leaves ( Figure 7 a,b).…”

“…The sandy soil, because it originated from the Caiuá sandstone formation, is characterized by low a CEC, due to its high sand content, especially coarse sand [ 87 ]. A low CEC directly affects cation losses, due to leaching, and consequently the expected crop yield.…”

Soil Fertility and its Relationship to Soil Mineralogy of some Areas in Southwest Sinai, Egypt

“…The highest O.M value was detected in profile 5while the lowest one was recorded for profile 4. Cation exchange capacity (CEC) was very low and did not excceed 3 cm molc kg -1 mostly due to the low contents of clay and OM (Costa et al, 2020). The lowest value of CEC was in profile 1 (2.64 cmolc kg -1 ) while the highest value (4.74 cmolc kg -1 ) was in profile 8.…”