Percolation and yield of different crop rotations

During seven years (April 1993 – March 2000), the effect of different crop rotations, grass-clover mixture, Miscanthus, and lay, on the amount of percolate and nitrate leaching to groundwater was investigated in lysimeters (1 m2 surface, 1.4 m depth) filled with a weakly humic, loamy sand (ortic luvisol). The experimental layout, and data for yield, percolate formation, and water balance are described.<br><br>The most important factors with respect to the formation of percolate are the timing and amount of precipitation, together with the type and duration of the plant cover. Crop rotation plays an important role with respect to water consumption and the related formation of percolate. Under rotations with cover crops, the formation of percolate was reduced by 10 – 15 %, as compared with rotations without or with a reduced presence of cover crops. Dry matter yield has no direct effect on the formation of percolate.