Groundwater Formation Below Chernozem Soils - Effect of Mineral Fertilization, Rainy and Dry Periods

Chernozem soil samples from the east of Austria have been packed into columns in order to investigate the effects of mineral fertilization on the composition of water, released to deeper layers. A solution imitating NPK fertilization was added on top of water-saturated columns, and washed down with 150 cm³ portions (about 0.1 pore volumes) every day except weekends, for 2 months. The eluates were collected and analyzed by ICP and AAS methods. After about one pore volume, a strong peak in alkali, alkaline earths, and sulfate occurred in the eluates, due to ion exchange with the fertilizer solution. After this, most concentrations in the eluates approached a steady state again, but lower than the levels met before. After a period of drying, the release of K and S, as well as P in 2 of 3 cases, increased, whereas the release of Fe and Mn decreased. Before the eluates entered the sample collection vessels, ochre precipitation scavenged many solutes (Cr > Al > Pb > P > V > Fe), but left Mo-Sr-Mg-K-Se-B rather untouched.