| Abstract: | Influence of fertilization on nitrogen leaching after cultivation of maize for silage over four successive seasons In a field trial, nitrogen leaching from soil was determined between February 1983 and May 1986 by analyzing soil water from 50, 80 and 110 cm below the soil surface every 14 days. On a Stagno-gleyic Luvisol, maize after maize was cultivated over four successive seasons. Nitrogen was applied either minerally in spring according to Nmin or as a semiliquid cattle manure. The time of application (autumn and/or spring), application rate and use of nitrification inhibitor dicyandiamide (DCD) were varied. Under very low N-fertilization (underground fertilization only), nitrate nitrogen losses by leaching dropped from 100 kg N/ha in the first year to 33 kg N/ha in the 3rd. Nitrogen leaching from the various treatment plots depended on the maize growth and rainfall conditions. Because of an intensive and long lasting seepage of gravitational water, nitrogen leaching from the root zone ranged from 113 to 208 kg N/ha during the fall and winter seasons of 1983/84 and 1984/85. Under the more balanced infiltration conditions of the leaching period 1985/86, and after a high yield of maize in 1985, losses due to leaching were reduced to values between 69 to 108 kg N/ha. Under these experimental conditions (deliberately high quantities of semiliquid cattle manure; DCD-application in autumn) no reduction in nitrogen losses could be proved due to the addition of dicyandiamide. |
