Sustainable land management by restoration of short water cycles and prevention of irreversible matter losses from topsoils.

Sustainable land management requires that water and matter (nutrients and base cations) are efficiently recycled within ecosystems so that irreversible losses of matter from topsoils are minimised. Matter losses are connected to water flow. The division of water into evapotranspiration that is loss-free, and seepage to groundwater or surface water flow that both carry material losses, is decisive in determining total losses of dissolved matter in a given catchment. Investigations of areal matter losses confirmed the instrumental role of vegetation cover. Areal matter losses measured in agricultural catchments in Germany were on average between 1-1.5 tons of dissolved matter per ha per year, i.e. some 50 to 100 times higher than those from unmanaged land in a virgin forest. Such high losses continuously reduce soil fertility and can hardly be compensated by fertilisation. Some suggestions on how to achieve sustainable management of agricultural land and maintain high soil fertility are presented - the priority is to close water and matter cycles through the incorporation of more natural vegetation cover into our landscapes and to restore the energy-dissipative properties of ecosystems.