Effects of the time of the application and the form of nitrogen on maize inbred lines yield and 1000-grain weight

The study was carried out in the experimental filed of the Maize Research Institute, Zemun Polje, on calcareous chernozem in the period 2001–2003. The grain yield and thousand grain weight of two maize inbred lines (IL1 — FAO 400 and IL2 — FAO 600) were observed in dependence on the time of nitrogen application and forms of nitrogen applied.Regarding time of fertilisation, the highest average grain yield was obtained by the use of Nmin method. Regarding the kind of nitrogen fertilisers, the highest average grain yield of observed maize inbred lines (3,264 kg ha−1) was obtained by the application of ammonium-sulphate in the primary autumn tillage (Nautumn). The use of the Nmin method (N ranging from 17 to 35 kg ha−1, in dependence on the soil mineral nitrogen content), especially in years with lower precipitation sums, resulted in the highest increase in grain yield (39.2%) and 1000-grain weight (3.2%) in observed maize inbred lines compared with the controls. The application of different forms of nitrogen did not result in statistically significant differences in 1000-grain weight in analysed maize inbred lines