engleski

Influences of ameliorative fertilization on yield and nutritional status of maize

Suboptimal levels of plant available nutrients are oft limiting factor of field crop yields under environmental conditions, especially in middle and northwestern 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 (<0.02 mg Cd kg -1).

maize ; fertilization ; liming ; phosphorus ; potassium ; yield ; nutritional status

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