Floods and other possible adverse environmental effects of meadowland areadecline in former West Germany

A large-scale conversion of permanent grassland into arable land was undert aken after World War II in West Germany to increase agricultural productivi ty. In the course of this process the total meadowland area decreased durin g the period 1965-1985 by 1.5 x 10(6) ha, or 6% of the country's total area . The environmental implications of this large-scale conversion have so far received little attention; the present study examined some of these implic ations. A review of research on soil physical and chemical aspects of the c onversion of permanent grassland into arable land reveals that such a large -scale conversion may have considerable effects upon the environment. For e xample, due to the mineralization of soil organic matter a release of NO3 a nd CO2 into the environment can be expected on the order of 10 t N and 100 t C per hectare. Environmentally equally severe, if not worse, is the incre ased amount of surface runoff that can be expected from converted grassland soils in arable land during winter because of surface sealing and soil com paction. This increased surface runoff, in combination with the runoff from other farmland, may be one of the reasons for the growing frequency of flo ods along major German rivers in recent years. In view of the lasting adver se environmental effects of permanent grassland conversion and the subsidiz ed agricultural surpluses in Germany today, we conclude that a reconversion of arable land into permanent grassland may be beneficial both environment ally and economically.