engleski

Response of corn (Zea mays L.) inbred lines to stress and potassium fertilization on K-fixing soil.

Potassium fixation and oversupply of magnesium are the main reasons for the appearance of potassium deficiency symptoms in maize plants, especially inbred lines, when grown on some drained gleysols of the Eastern Croatia. In the spring of 1990 field trial of increasing potash rates until 3250 K2O/ha was conducted. For the next growing season residual influences of ameliorative fertilization were tested and experimental field was usually fertilized (for corn: 240 kg N + 125 kg P2O5 + 150 kg K2O/ha). In the growing season of 1993, different corn hybrids and inbred lines were grown on this place (four replications, experimental plot 18.2 m2). In this study, response of six inbred lines was shown. As affected by 3250 kg K2O/ha application, they were increased grain yield by 112% and ear-leaf K (silking stage) by 200% compared to ordinary fertilization. At the same time, they decreased lodging incidence by 72% and ear-leaf Mg by 48%. Degree of inbred lines tolerance toward soil stress (ordinary fertilization) was different. For example, depending on inbred lines, grain yields ranged from 0.73 to 1.85 t/ha, lodging incidences from 3% to 51%, while ear-leaf composition ranged as follows (mg/100 g on dry matter basis): from 414 to 621 K, from 951 to 1458 Mg and from 751 to 1335 Ca. Analogous values on treatment of ameliorative K rate were as follows: 1.97-3.42 t/ha (yield) ; 3-24 % (lodging) ; from 1074 to 1907 K, from 442 to 1049 Mg and from 659 to 1203 Ca. In general, low connection was found between ear-leaf composition and degree of inbred lines tolerance toward soil stress.

corn ; nutritional stress ; potassium ; magnesium ; calcium ; potassium fertilization

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