Effects of nitrogen splitting and source on durum wheat

Optimum nitrogen fertilizer management for wheat production is important for maximum economic yield and minimum pollution of the environment. A lysimetric trial was conducted in Central Italy during 2008-2009 and 2009-2010 on durum wheat varieties Latinur and Svevo to evaluate effects of ammonium sulphate and Entec 46 at sowing, of ammonium sulphate and urea at topdressing and of three split applications (0-90-90, 30-75-75 and 60-60-60 kg N ha-1) of the same amount of nitrogen on grain yield and yield components, N uptake and N leaching. Grain yield was higher in Latinur than in Svevo. The highest production was achieved in 2009 with the 60-60-60 splitting, and in 2010 with 0-90-90. In both years, the highest total N uptake was recorded with the 30-75-75 splitting, regardless of N source. Nitrogen leaching increased with the increasing amount of N rate at sowing. Amount of N-NO3 lost by leaching during wheat cycle was 25 kg ha-1, almost entirely accounted for N leaching in the period November-January.