engleski

Influence of inheritance and potash fertilization on zinc, manganee and iron status in corn (Zea mays L.)

Strong fixation of K and Mg oversupply are main reasons of fertility limitation in some gleysols of Posavina lowland. In this study was shown zinc, manganese and iron status in corn hybrids as affected by ameliorative K fertilization, while K and Mg status were shown by the earlier study. The field trial of increased K fertilization (in KCl form until level of 3250 kg K2O ha-1) was conducted on strong K-fixing soil in the spring of 1990 (randomized block design in four replications). In the next three years, entire trial area was fertilized uniformly (ordinary fertilization). In the fourth year of testing (the growing season of 1993) different corn hybrids were grown on this field. Corn was sown in term of April 28, and it was harvested in the term of September 24, 1993. Grain yields were calculated on the realized plant density and 14 % moisture basis. The ear-leaf samples (30 leaves in mean sample) was taken at beginning of the silking stage (the middle of July). Six corn hybrids and four levels of K fertilization (Table 2) were choose for leaf analysis. Plant and soil nutritional status were determined by using ICP technique. Soil was classified as drained gleysol on calcareous loess substrate. Low exhangeable K and high exhangeable Mg, as well as low Zn, Mn and Fe were found by soil test. As affected by applied fertilization corn grain yields were in range from 1.83 t ha-1 (150 kg K2O ha-1) to 7.04 t ha-1 (3250 K2O ha-1). Differences of grain yields among corn hybrids were in range from 4.35 t ha-1 (Bc 66-61) to 5.31 t ha-1 (OsSK 407). Also, considerable influences of hybrid and K fertilization on plant density realization were found. In general, low concentrations of zinc (23.2 mg Zn kg-1), manganese (15.7 mg Mn kg-1) and iron (130 mg Fe kg-1) were found in dry matter of the ear-leaf of corn at silking stage. Significant influences of inheritance (differences among the hybrids) were found with ranges of variations as follows: from 18.9 to 26.5 mg Zn, from 14.2 to 17.2 mg Mn and from 120 to 142 mg Fe kg-1. As affected by potash fertilization, ear-leaf Mn and Fe concentrations decreased, but the ear-leaf Zn was increased. However, plant K and Mg nutritional status were considerably improved by potash fertilization as follows: 0.31% K (acute K deficiency) and 1.08% Mg under stress (ordinary fertilization) ; 1.18% K and 0.47% Mg (3250 kg K2O ha-1), respectively. Also, differences of ear-leaf K status between OsSK377 (0.37% K) and Bc66-61 (0.26% K) hybrids could be in connection with differences of their grain yields (2.47 and 1.54 t ha-1, respectively) on the control. Grain yields of corn hybrids and ear-leaf Zn, Mn and Fe concentrations were under influences of environmental and genetic factors. In general, under soil stress conditions induced by K deficiency and Mg oversupply, corn grain yields were even 75 % lower. Increased K fertilization and growing of more tolerant hybrids are directions of corn production improvement on these problem soils. Also, fertilization with manganese and iron could be additional contribution to grain yields increases on K-fixing gleysols in Croatia.

Corn; Inheritance; Potash; Fertilization; Zinc; Manganese; Iron

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