Die Bodenkultur - Journal for Land Management, Food and Environment
A. FIEGENBAUM, W. AUFHAMMER and E. KÜBLER:
Nitrogen accumulation and nitrogen residues of field beans (Viciajaba L.) Part 2: Development of the Nmin-content of the soil after field beans
The objective of the investigations was the development of the Nmin-content of the soil after field beans, returning between 70 and 170 kg N/ha by vegetative residues. Field experiments were conducted in 1990 at one location (Ihinger Hof) and in 1991 at two locations (Ihinger Hof, Oberer Lindenhof). Factorial variation included with/without residues and with/without soil preparation after harvest. Commencing at the harvest date at 6 to 8 dates until April/May soil samples (0 to 90 cm) were taken to analyze the Nmin-content. Additionally after harvest small lysimeters containing the 0 to 30 cm soillayer were put in especially choosen plots of the Ihinger Hof -1991 experiment. Continuously the percolated water amounts were collected to analyze the N03-N-content. Furthermore groups of soil columns (0 5 cm) of the 0 to 30 cm soillayer were taken and incubated for 16 weeks at 20°C and 35 "C, respectively. At five consecutive dates during this period the NOs-Nccontent was analyzed.
During autumn in all field experiments Nmin-contents (0 to 90 cm) increased.
Interactions between years and soil preparation after field bean harvest determined the further development of the Nmin-content. In contrary to results of the period investigated in 1990/91, soil preparation seemed to decrease Nmin-Ievels of field plots and especially of incubated soil columns in 1991/92. Nevertheless Nmin-Ievels between 30 and 60 kg N/ha and the results of the lysimeters indicated available N03-N-amounts and NO3-N-translocation during the investigated period.
Key-words: field beans, N-residues, Nmin-content/soil.