The investigations were carried out by field experiments at the locality of Oborovo (near Zagreb). The three-factorial experiments were set by Strip-plot method in five repetitions. There were four maize planting dates, (a day or three days at the most after harvest 5 wheat varieties Superzlatna, Adriana, Sana, Marija, Olga) July 2, 5, 10 and 18 in 1994, and July 10, 11, 14 and 24 in 1995 and three hybrids Bc 175 from FAO 100, Bc 222 from FAO 200 and Bc 318 from FAO 300 maturity group were used. Quantity and quality of maize yields in doublecropping system were different in regard to planting date, hybrid used and the characteristics of maize growth season. After early wheat harvest dates in 1994, maize accumulated 900-1000 heat units in the first three maize planting dates. That enabled hybrid maturity groups 100-300 to have 25-30% dry matter in green mass of the whole plant, which makes mass convenient for silage. Hybrids planted on first and second planting date (Bc 175) had favorable 50% of ear content while (Bc 222 and Bc 318) had about 40%. Total dry matter yield was high - from 6.7-7.1 t*ha-1 (Bc 175) to 8.4-9.6 t*ha-1 (Bc 222 and Bc 318). Due to the later wheat harvest dates in maize growth season in 1995, the maize accumulated less than 900 heat units and, respectively of a hybrid, maize was in milk stage with mean dry matter content from 15-20%. Although the yields of dry matter (6.4-8.4 t*ha-1) were relatively high, maize could only be used as green fodder.

doublecropping system; maize; silage mass; total dry matter yield

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia