**5. Conclusion**

The investigations after the flood in central Norway in 1995 showed that flooding of 2–9 days duration caused decreased yields of cereals as spring barley, spring wheat, and oats. As sufficient N-supply after end of the waterlogged period could bring the yields of barley and oats up to normal levels, it is likely that the flooding with cold running water caused delayed development and maturing of the crop and the fertilization could compensate for N leaching during the flood.

Reconstruction of erosion craters and other measures to make the damaged agricultural areas into agricultural production showed large differences between the best and the least successful measures. The restoration measures gave as a mean about 85% of the yield compared with areas without damage or eroded topsoil. Filling erosion craters with loamy fine sand and mixing in limed sewage sludge gave similar yields as the undamaged areas. This treatment significantly increased the amount of readily available P in the soil, while use of another type of sewage sludge had no positive effect on the yields.
