Based on Sr isotopic ratio and element concentration, soil water- and NH4 acetate leaching indicates (1) a dominant manure/slurry contribution in the top soil, representing a cation concentrated pool, with low 87Sr/86Sr ratios; (2) in subsoils, mineral dissolution is enhanced by fertilizer application, becoming the unique source of cations in the saprolite. The relatively high weathering rates encountered implies significant sources of cations which are not accessory minerals, but rather plagioclase and biotite dissolution.
Stream water has a very different isotopic and chemical composition compared to soil water leaching suggesting that stream water chemistry is dominated by elements issued from mineral and rock weathering. Agriculture, by applications of chemical and organic fertilizers, can influence the export of major base cations, such as Na+. Plagioclase dissolution, rather than anthropogenically controlled soil water, seems to be the dominant source of Na+ in streams. However, Ca2+ in streams is mostly derived from slurries and manures deposited on top soils, and transferred into the soil ion-exchange pool and stream waters. Less than 10 % of Na+, 5–40 % of Sr2+ and 20–100 % of Ca2+found in streams can be directly derived from the application of organic fertilizers.