The effect of fertilisation on the quantity of grain crops has been long studied. As a result, many researchers have already proven that the most decisive intervention in the agronomic practice in order to increase the yield is nutrient replenishment. Yield has a great impact on farm revenue, nutrient supply has an impact on costs; therefore, the realisation of income in respect to both of them has a significant role.

In this study, the nutrient replenishment circumstances of maize production were examined while focusing on the economic conditions.

Experiments were carried out at the research site belonging to University of West Hungary Faculty of Agricultural and Food Sciences on a 15.3 hectare experimental area. During the experiment, NK Furio corn hybrid was used. Based on the nutrient reaction functions we defined the functions of income. A derived quadratic equation showed where it would be possible to reach the highest profit concerning the applied amount of fertiliser.

Summarising the results, we have calculated the achieved incomes for each treatment units and mapped them with ArcView/ArcMap 9.2 software. According to the results, differences on the realisable profit can be mapped and visualised.

Based on our results we can conclude that the applied advisory system recommends higher amount of fertiliser for the treatment units compared to the economical optimum. It can be recommended that in the advisory system the variability of a given hybrid genotype should be taken into consideration in order to achieve higher income.

With the help of the profit maps, the within field variability can be easily visualised; therefore, application of such maps can be strongly advised for the theoretical approaches as well as for the farmers in the practice.

Keywords: site-specific nutrient replenishment, profit map, profit optimisation