The aim of this study was to analyse the problems caused by the unfavourable (dry and wet) weather and its consequences in the R1 growth stage of maize (Zeamays L.), as well as their management and the alternatives of preventing yield reduction by using agrotechnical measures fertilisation, irrigation), also, we wanted to examine whether the Chl content measured in the R1 growth phase provides reliable prediction of yield per hectare.

The examinations were carried out in a moderately warm and dry production area at the Látókép Experiment Site of the University of Debrecen, Centre for Agricultural Sciences on calcareous chernozem soil in 2007 and 2008. Six different N doses (0,30,60,90,120,150 kg ha-1) were used in the irrigated and non-irrigated treatments of the field experiment.

The results showed that there is a significant strong positive correlation between Chl content and yield both in the non-irrigated (P<0.001, R=0.777) and the irrigated (P<0.001, R=0.801) treatment. The results of the correlation analyses performed yearly showed that weather factors significantly influence the strength of correlations, but these correlations are always positive.

The Chl content of maize leaves provided a reliable prediction of yield per hectare in the R1 growth stage. In the irrigated treatment, the correlation is always closer than in the non-irrigated treatment.