Yield potential and nitrogen dynamics of no-till silage maize (Zea mays L. under maritime climate conditions

摘要

In intensive dairy farming in Northwest Europe resource-efficiency of forage production based on permanent grassland in combination with continuous maize is undermined by high nitrogen surpluses. With respect to the paradigm of ecological intensification (EI), a field experiment was set up in northern Germany to answer the question of whether rotational fodder production including silage maize (Zea mays L.) and grassland combined with no-till soil cultivation represents an alternative to conventional tillage. A 10-year-old grassland sward was converted to maize in two ways: (i) with conventional tillage (CT) and (ii) with no-tillage (NT). There were two rates of N-fertilization: fertilized (N1), (grassland 380 kg N ha(-1), maize 90 kg N ha(-1)) and unfertilized (NO). Aboveground net primary production (ANPP) was not significantly different in Ni treatments, with average maize yields of 18 (NT) and 21 t ha(-1) (CT). Belowground net primary production (BNPP) showed similar biomass production in NT and CT. N-release from the old sward made additional fertilization unnecessary in the first year. A beginning differentiation between both tillage systems in the second year showed a significant decline in N-yield and N-release in NT NO treatments. However, crop performance and N-release in Ni treatments continued to be comparable to CT. In terms of N leaching, tillage intensity had no clear effect on drainage N-losses. We conclude that due to comparable yields in both tillage treatments, no-till maize cropping following several years of grassland leys can contribute to EI by saving N-fertilizer input.