The influence of agriculture and settlement on the mire valley landscape and as well as the role of tree-covered belts in halting of pollution from arable land were examined. The natural mire valley landscape is slightly influenced by human activity, which consists in supplying the valley margins in N, P and K from arable land. The groundwater supplies the valley margins in Ca and HCO3-, whereas the river water brings N, P, K in area of river flooding and Mg, Cl- and Fe in the river margins zone. In the drained valley the human impact on landscape appears in changes of habitats, soils and vegetation which is related mainly to new water conditions caused by new river-bed. However human activity has an impact on the hydrogeochemical processes. The peatland is enriched with anthropogenic pollutants: K, Mg, Cl- and HCO3-. The valley margins are supplied with N, P and Fe leaching from arable land. Moreover, N, P and Fe are released in the mucking process. The tree-covered belts situated on the valley margins play a significant role in stopping pollution.