@article{fdi:010090760,
  title = {{R}ole of clay cation exchange capacity, location of charge, and clay mineralogy on potassium availability in {I}ndian {V}ertisols},
  author = {{G}urav, {P}. {P}. and {R}ay, {S}. {K}. and {D}atta, {S}. {C}. and {C}houdhari, {P}. {L}. and {H}artmann, {C}hristian},
  editor = {},
  language = {{ENG}},
  abstract = {{P}recise information on the location of charge in clay minerals and their charge density in smectite-dominant soils is rare. {T}he present study was undertaken with three benchmark {V}ertisols to establish the relationship between the clay cation exchange capacity ({CEC}), charge density, as well as the location of charge in smectitic soil clay minerals and their relationship with potassium ({K}) fixation and release. {P}otassium fractions and their threshold levels in the {V}ertisols were determined by standard methods. {S}oils were segregated into silt, total clay and fine clay fractions for {X}-ray diffraction analysis and fine clay fractions were used to determine the {CEC} using standard methods. {T}he {H}ofmann-{K}lemen effect ({HK}) and modified {G}reene-{K}elly test was done with the fine clay to determine the {CEC} of the tetrahedral sheet. {S}ubsequently, the {CEC} of the octahedral sheet was calculated as the difference between total {CEC} and the tetrahedral {CEC}. {T}he results showed that similar to 60-64% of the total {CEC} is attributed to the tetrahedral layers. {T}he tetrahedral {CEC} that is proportional to the tetrahedral charge density was significant and negatively correlated with {K} release threshold values and all fractions of {K}. {T}he tetrahedral {CEC} contributed more toward the {K} fixation and release than the octahedral {CEC}. {T}he study shows that the dominant presence of high-charge smectites in the fine clay fractions of these {V}ertisols contributed to the tetrahedral {CEC} and consequently to the charge density of these soils, which implied a tendency to fix {K} easily and release it with greater difficulty compared to soils with low-charge smectites.},
  keywords = {charge density ; {K} fixation and release ; octahedral {CEC} ; smectites ; tetrahedral {CEC} ; {V}ertisols ; {INDE}},
  booktitle = {},
  journal = {{C}lays and {C}lay {M}inerals},
  volume = {72},
  numero = {},
  pages = {e3 [11 p.]},
  ISSN = {0009-8604},
  year = {2024},
  DOI = {10.1017/cmn.2024.6},
  URL = {https://www.documentation.ird.fr/hor/fdi:010090760},
}