Response of grain yield of some maize lines grown in calcareous soil to potassium fertilization [electronic resource].

Includes references.

Three successive field experiments were conducted, during summuer seasons of2003, 2004 and 2005 at Nubaria Agriculture Research Station to study the effect of potassium fertilization on grain yield of five maize (Zea mays L.) lines grown In calcareous soil Four rates of potassium, as potassium sulphate fertilizer, (0.0, 0.0571, 0.1140 and 0.1713 Mg K2O ha-1), and flve maize lines: Sd.7, Gz.602, G:.612, Gz.62B and Gm.2 were used. Data were recorded for grain yield (Mg ha-I). Five polynomial quadratic equation were used to express the relation between grain yield of maize lines and pottassium rates. The following results were obtained: Highly significant differences of grain yield were observed for yean, potassium rates (K), maize lines and their interaction. Overall mean of grain yield increased from 2.71 (no , K2O) to 3.59 Mg ha-1 (0.1713 Mg K2O ha-1). The highest grain yield was obtained from Gz.602 line (3.98) followed by Sd. 7 (3.47 Mg ha-1), while the lowest yield was obtained from Gm.2 (2.34 Mg ha-1). The maximum rates of potassium (X-J ranged from 2. 745 to 6.390 units of K2O ha-1 (one unit of K2O ¬ 0.0571 M, K2O ha-1). The hi,hest value belonged to Gz.612 and the lowest value belonged to Gz.62B. The optiassium rates of potassium (Xopt ranged from 2.734 to 5.555 units of K2O ha-1with an average 3. 758, the lowest value belonged to G:.628 and the highest value belonged to Gz.612.The values of Ymax.for potassium fertilizer ranged from 2.676 to 4.415 Mg ha-1with an average 3.271 Mg ha-1 while the lowest value of maximum yield belonged to Gm.1 and the greatest value of (YJ belonged to Gz.612) The optimum grain yield of maize lines ranged from 2.665 to 4.410 Mg ha-' with an average 3.713 Mg ha the highest value of Yopt, belonged to Gz.602 and lowest values belonged to Gm.2.The economic return values for the studied lines ranged between 3306. 70 and 5680.30 EP ha-1Egypdan pound / hectare), with an average 4535.10 EP ha-1, the highest value of return belonged to Gz..612 and the lowest value belonged to Gm.2. The net return values obtained from the studied lines ranged from 2578.1/ to 4357.65 EP ha-1, with an average 3637.23 EP ha-1, while the lowest value belonged to Gm.2 and the highest value belonged , Gz.612. The returns per each I EP for the applied optimum rat of K2O , ranged from 3.17 to 5.93 EP II EP, with G average 4.34 EP. The lowest value belonged to Sd. 7 and the highest value belonged to Gz.602.

Summary in Arabic.

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