ABSTRACT
Urea is the main source of N in Argentina with 62% of the N fertilizer market. However, urea ammonium nitrate, with 16% of the market share, is frequently used in maize, especially in V4-V6 applications. The use of urease and/or nitrification inhibitors is still limited; however, field research has shown interesting results in different regions and conditions (Sainz Rozas et al., 1999; Ferraris and Couretot, 2011; Fontanetto et al., 2011). Research has shown that N applications at V5-V6 stage are more efficient than pre-plant or planting applications (Sainz Rozas et al., 1999, 2001; Pagani et al., 2008). Farmers applying N at this stage mostly dibble UAN, and in some cases ammonium thiosulphate, which also provides S. Split applications up to V10-V12 stage have also shown that synchronicity of N supply with demand would greatly increase N use efficiency (Melchiori, 2012) by reducing N losses by leaching and/or denitrification (Sainz Rozas et al., 2001).
