For a better understanding of soil nitrogen dynamics in maize cropping systems, Nmin content of soil and soil water samples from 0 to 100 cm depth were measured periodically in a loamy Cambisol near Zurich, Switzerland, from 1998 to 2000. Maize was sown either with conventional tillage (CT), rotary band seeding (RBS), or no-tillage (NT) after a previous crop of ryegrass and red clover. NT was also used after different annual green manure crops. Weeds were controlled with herbicides and a total amount of 145 kg N/ha was applied in three split applications to the maize plant rows. Between sowing of the maize crop and the 6-leaf stage of the plantlets, nitrogen dynamics were mostly influenced by the weather conditions and the intensity of soil tillage: In 2000, when the weather was warm, the maximum Nmin content in the soil after an application of 90 kg N/ha was 250 kg N/ha in all tillage systems. However, in 1999, when the weather was cool and humid, Nmin content in the soil was 50 % lower than in 2000. The ranking of the calculated N leaching losses was NT before RBS and CT, probably due to a delayed nitrogen mineralization and a higher water content in the soil after NT in contrast to RBS and CT. When N-fertilization was adapted to plant needs, most of the available mineral nitrogen in the soil was taken up by the maize plants during the 8-week period of fastest growth from the 6-leaf stage to milky ripe stage and the Nmin content in the soil after harvest of the maize crop at the end of September did not exceed 20 kg N/ha. In conclusion, NT and to a lesser degree also RBS are recommended as cropping systems for the improvement of soil structure and for the prevention of nitrate leaching.
Bender S.F., Schulz S., Martínez-Cuesta R., Laughlin R.J., Kublik S., Pfeiffer-Zakharova K., Vestergaard G., Hartman K., Parladé E., Römbke J., Watson C.J., Schloter M., van der Heijden M.G.A.
Gilgen A., Felder R., Baumgartner S., Herzog F., Jeanneret P., Séchaud R., Paunovic S., Merbold L.