The CULTAN system in a screening test for Swiss arable farming

The CULTAN (Controlled Uptake Long Term Ammonium Nutrition) system was tested on farmers fields in the Swiss Midlands from 2008 to 2010. In plot trials with winter wheat and grain maize, liquid ammonium sulphate was applied in a single dose according to the CULTAN system and compared with ammonium nitrate and ammonium sulphate, which were spread over the whole area with a pneumatic fertiliser spreader. For winter wheat, no differences were detected between the systems tested in terms of either grain yield or protein content. Straw yield was slightly higher with the CULTAN system, since more stalks per unit of area were formed. Nor did we find any differences for grain maize in terms of grain yield and nitrogen content between the CULTAN and conventional fertilising systems. Total dry-matter yields for the CULTAN system were slightly higher owing to the higher stalk yields. The placement of ammonium deposits in the soil, and hence the steady, long-term feeding of the plants with ammonium intended by the CULTAN system, could not be confirmed in the trials. Ammonium and nitrate measurements in the soil have shown that the ammonium is almost completely nitrified within just a few weeks.