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In addition, mineral weathering produces cations that counteract soil acidification, thereby improving the availability of most plant nutrients \citep{van_Breemen_1983}.   Also clays are formed as a weathering product of feldspars and micas \citep{Oades_1988}.   Clay particles contribute, with their negative charged surfaces, to the cation exchange capacity (CEC) of the soil, reducing the leaching of positively charged nutrients like K+ K⁺  and NH4+. NH₄^{+}.  Clay content correlates positively with water holding capacity and soil organic matter (SOM) content \citep{Sollins_1996}.  Moreover, the weathering of Ca- and Mg-silicate minerals play a central role in the global carbon cycle.