The Influence of the Method of Use and Fertilization of Foothill Soil on the Concentration and Load of Trace Elements Leached into the Soil Profile by Percolating Water

The aim of this study was to assess the impact of the method of use and different fertilization of the foothill soil on the manganese (Mn), copper (Cu), cadmium (Cd) and lead (Pb) concentration in leachates and the loads of trace elements leached from the soil profile. An experiment was carried out in Wiśnicz Foothills (Malopolska Province, Poland). In each plot, three lysimeters were installed, placed at a depth of 0–30 cm. The experiment included six variants, five on meadow, without fertilization (A—control); with mineral fertilization (B); with liquid manure (C) and with manure application (D); non-fertilized and non-mowed (E); and on arable land with mineral fertilization (F), in three repetitions each. Leachates were collected for three years in three periods: I—intensive growing, II—slow growing, and III—non-growing seasons. In general, the highest concentrations of Mn, Cu, Cd and Pb were recorded in leachates during period III. The lowest amounts of Cu and Cd were found in leachates in period II and Mn and Pb in period I. The exception were leachates from the following treatments: fertilized with liquid manure, which contained the most Mn and Cd in period II and the least Cd in period I; unused meadow, which contained the least Pb in period I; and leachates from arable land contained the least Cd in period I. The differences in the content of trace elements in the leachates were significant and amounted to 150–200% for Cd and Pb and about 20% for Mn and Cu. Mineral fertilization generally did not affect significantly Mn, Cu, Pb and Cd content in relation to the control, and the contents of Mn, Cu and Pb were even lower than in the leachates from the control. There was a significant increase in Mn concentration in leachates from unused meadow and arable land, Cu, Pb and Cd after both natural fertilizer applications and from arable land compared to other objects, in addition to Cd from unused meadow. Generally, the highest loads of trace elements were removed in period II and the smallest in period I of the study. Differences in leached loads during these periods were 2- to 8-fold and greater after liquid manure and manure application. The differences in Mn, Cd and Pb loads in subsequent years were 1.5- to 2-fold, and Cu loads in all years were similar. Natural fertilizers increased the trace element loads 1.5–4-fold compared to the control. Smaller differences concerned Mn and Cu and larger Pb loads. The method of land use significantly affected the quantity and quality of water percolates through the soil profile. Contrary to popular belief, the leachates from the unused meadow were not of the best quality, which resulted from their increased permeability into the soil under these conditions. Due to the quantity and quality of leachate waters and surface runoff in the foothill and mountain areas, it is advisable to limit tillage treatments, and the rational use of meadows and pastures with moderate fertilization is recommended. It is important to emphasize the importance of the proper management of the use of foothill and mountain areas for the optimal supply of plants with trace elements. Substantial losses of microelements necessary for optimal plant development may require their use in the form of fertilizers, which will result in increased agricultural production expenditures, reduce economic effects and slow down the pace of achieving sustainable agriculture.