engleski

Response of corn hybrids to liming

Soil acidity is certainly one of the most damaging soil conditions affecting the growth of most crops. A combination of soil management practices, liming in association with corrective levels of P, and use of crop cultivars developed for these low pH conditions is a solution encountered for improvement of maize production in acid soils. Soil acidity is in many cases limiting factor of arable crops yield in Croatia. The field experiment was conducted on planosol in spring 1993 by split-plot method in four replicates (pH in 1n KCl = 4.27; humus = 1.82%; AL-method = 10.3 mg P2O5 and 20.1 mg K2O/100 g of soil). Fertilization was designated as the factor A (exp. plot 352 m2) with treatments as a follows: a1) control (ordinary fertilization: 180 kg N + 100 kg P2O5 + 125 kg K2O/ha) and a2) control + liming with sludge of Osijek sugar beet factory containing 37% CaO. Sludge (15 t/ha) incorporation was made before sowing until about 15 cm of soil depth by soil tillage treatments. Corn hybrids were designated as a factor B (experimental plot 7.7 m2 = 11-m long row). Corn was sown manually in term 27 April 1993. It was sown 3 seed with 50 cm spacing in the row. At early growth of corn (3-4 leaves stage) was reduced number of plants by plucking (two plants in 50 cm spacing: theoretical plant density = 57 144 plants/ha). Corn grain yields were calculated on 14% moisture basis and 90% realization of theoretical plant density. Ear-leaf was taken for chemical analysis at beginning of the silking stage (in middle July) from each plot. Mean sample contained about 25 leaves. Plant samples were prepared for chemical analysis by drying and grinding. These samples were digested by dry-ashing procedure for P (molibdat-vanadate method), K Ca, Mg and Zn (atomic absorption) determination. N was determined by Kjeldahl procedure. In general, grain yield increase as affected by liming was about 23% (mean yields 6.47 and 7.94** t/ha, for control and liming, respectively). Realized plant density and grain moisture were independent on fertilization (means 91.2% and 27.5%, respectively). Four hybrids (OsSK262, OssK218, OssK377 and OsSK553: mean yield 5.54 t/ha) could be designated as less tolerant, three hybrids as relative tolerant (OsSK456, Bc6661 and OsSK502: mean yield 6.47 t/ha) and remaining three hybrids (OsSK382, OsSK552 and OsSK644: mean yield 7.66 t/ha) tolerant to acid soil stress. Grain yield increases of corn hybrids as affected by liming were from 6% (OsSK382) to 45% (OssK502). Ear-leaf composition (in dry matter) at beginning of silking stage (means of ten hybrids for control and liming, respectively) were as follows: 2.99 and 3.15**% N, 0,272 and 0.278%P, 1.99 and 1.91**%K, 0.93 and 0.93 %Ca, 0.28 and 0.35 ** %Mg, 38.0 and 35.4* mg Zn/kg, respectively. In general, hereditary influences on ear-leaf composition were higher than liming influences. For example, these differences among hybrids (control treatment) were as follows: from 2.70 to 3.27**% N, from 0.233 to0.296%**P, from 1.80 to 2.16%** K, from 0.73 to 1.12**% Ca, from 0.19 to 0.33**% Mg and from 31.3 to 45.0** mg Zn/kg.

corn; hybrids; liming; nutrients

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