Joint International Conference on Long-term Experiments ...

INFLUENCES OF AMELIORATIVE FERTILIZATION ON YIELD
AND NUTRITIONAL STATUS OF MAIZE
Kovačević Vlado , Josipovic Marko 2 , Stojić Biserka 3
1 University J. J. Strossmayer, Faculty of Agriculture HR-31000 Osijek, Croatia
2 Agricultural Institute, Juzno predgradje 17, HR-31000 Osiejk, Croatia
3 Petrokemija d.d. Fertilizer Factory HR-44320 Kutina, Croatia
ABSTRACT
Suboptimal levels of plant available nutrients are oft limiting factor of field crop yields
under environmental conditions, especially in middle and north-western part of Croatia.
Farmers mainly have not basic information about their soils (for example, their
agrochemical characteristics). In frame of education of farmers in Djulovac (Bjelovar-
Bilogora County), Pakrac (Pozega-Slavonia County) and Okucani (Brod-Posavina
County) municipalities during March of 2003 total 108 soil samples (0-30 cm depth)
were taken form unfertilized fields (total 279 ha) and soil testing was made (soil pH,
plant available phosphorus and potassium according AL-method). About 60% of tested
soil samples are acid ( pH in KCl less than 5). Also, about 40% of soil samples are poor
or moderate supplied with phosphorus (P), while potassium (K) status is better because
only 13% samples are in this range of K availability. Based on soil test, choice of plots
for fertilization experiment was made. Aim of this study was testing of ameliorative
fertilization (spring 2003) with P and K in form of NPK fertilizer on yield and
nutritional status of maize (the growing seasons 2003-2005). In the second and third
year of testing only standard fertilization of the experiment was applied. Maize
responded to applied fertilization by moderate yield increases up to 10% only. We
presume that Al-method is not suitable solution for prediction of plant available P status
in this soil. Ameliorative fertilization resulted by significant influences on increased
plant available P, K and Fe status in the soil, while differences of the other tested
elements (S, Ca, Mg, Mn, Zn, Cu and Cd) were in level of statistical error. The applied
fertilization had the most influences on maize nutritional status in the first year of
testing (2003) because significant differences for P, K, Mn (increasing trend) Ca, Mg,
Mn and Zn (decreasing trend) were found. In the second year (2004) non-significant
differences were found, while in the third year (2005) significant differences were found
for P, K and Mg only. It is important that cadmium status in maize plant was
independent on applied fertilization because there are examples in literature that
application of the high P rates is mainly in connection with increases of Cd
concentrations in plant. Ameliorative fertilization had mainly low influences on maize
grain composition because only in the third year of testing significant differences for K,
Mg (increases) and Zn (decrease) status were found. Cd concentrations in maize grain
were under detectable range of the applied method (