engleski

Maize yields variation among years as function of weather regimes and fertilization

The field experiment with P and K fertilization was conducted in spring 2004 (a = ordinary fertilization, b = a + P1, c = a + P2, d = a + P3 , e = a + K1, f = a + K2, g = a + K3 , h = a + P2K2). The amounts of added either/or phosphorus (P2O5) and potassium (K2O) were (kg ha-1) 500, 1000 and 1500, for the step 1, 2 and 3, respectively. The triplephoshate enriched with sulphur and zinc (45% P2O5 + 1-2% S + 0.06% Zn) was used for P fertilization. Potassium salt (KCl containing 60% K2O) was source of K. The experiment was conducted in four replicates. The measured experimental plot was 77 m2. In the next years the experiment was fertilized uniformly in level of usual fertilization. Crop rotation since 2004 has been as follows: maize (2004) – soybean (2005) – maize (2006) – wheat (2007) – maize (2008) – maize (2009) – soybean (2010) – maize (2011). Mean maize yield in the experiment (t ha-1) was 12.78 (2004), 10.73 (2006), 11.70 (2008), 10.27 (2009) and 8.34 (2011). Mean of precipitation and air-temperature in the May-September period (Daruvar Weather Bureau) were as follows: 384 mm and 17.7 oC (2004), 407 mm and 18.4 oC (2006), 430 mm and 18.6 oC (2008), 231 mm and 19.5 oC (2009), 269 mm and 19.6 oC (2011), while long-term means (1961-1990) were 427 mm and 18.2 oC. Mean maize yield (the hybrids of the early maturity FAO group 200-300: t ha-1) in the experiment were in close connection with water supplies by precipitation and air- temperatures: 12.78 (2004), 10.73 (2006), 11.37 (2008), 9.78 (2009) and 8.34 (2011). In general, application of both P and K fertilizer in ameliorative amounts (the P2K2 treatment) resulted with significant increase of maize yields in level from 7% to 16%, compared to the control. Under drought stress conditions in 2009 and 2011 growing seasons their effect were 14% and 16%, respectively.

maize yield ; weather conditions ; precipitation ; air-temperature ; fertilization

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