Modelling climatic erosivity as a factor for soil erosion in Denmark: changes and temporal trends

Daily measurements of precipitation and temperature at 82 locations in Denm ark for periods of 10 to 43 years, were used for calculation of the impact energy and intensity of rain, climatic erosivity (hereafter called erosivit y). The computed erosivity values were analysed for trends and variations i n time and space. Analysis of 43 years of data from 6 locations showed a ch ange in the annual distribution of intense (erosive) precipitation, with a tendency to bi-modality, increasing erosivity in September, and decreasing erosivity in August. Amounts of precipitation in autumn have generally incr eased, but the erosive power of rain has increased even more. The geographi c location of high erosivity varied considerably from year to year. Using a simple crop model, the interaction between crop cover and erosivity was in vestigated. This suggested that changes in climate in combination with chan ges in cropping and management practice have increased risk of serious eros ion over the period 1954 to 1996. We recommend that present and future crop ping and management practices be evaluated for risk of adverse interaction with high erosivity events.