Authors:V. Kovačević, M. Rastija, D. Rastija, M. Josipović and M. Šeput
Five maize (
L.) hybrids were grown for four growing seasons on gleysol characterized by moderate supply with potassium (K). Three rates of KCl were applied in four replicates at the beginning of April 2001 as follows (kg K
O/ha): 150 (control), 650 and 1400. The highest rate of KCl resulted in significant increases of yield of 14%, 24% and 12%, for 2001, 2002 and 2003, respectively; while in the fourth year similar yields to the control were found. The OsSK552 and Bc5982 hybrids (4-year mean 8.70 t/ha) were more susceptible to soil stress in comparison with OsSK444 and OsSK458 (mean 9.07 t/ha). At the same time, Florencia hybrid yielded 9.37 t/ha. Four hybrids responded similarly to applied fertilization (yield increases from 13 to 16% in comparison to the control), while Florencia had low response to KCl (yield increase for 5% only). Under these conditions we recommend combined solution using 1000 kg K
O/ha every third year and a choice of tolerant hybrids.
Authors:M. Marković, P. Pepó, M. Sárvári, V. Kovačević, J. Šoštarić and M. Josipović
In the decade from 2000 to 2009, the yield of maize grain in Croatia varied from 4.2 t ha−1 (2003) to 8.0 t ha−1 (2008). The yield variation was mainly caused by weather conditions unfavourable for maize production, meaning lack of precipitation, unevenly distributed during the vegetation season, and mean air temperatures above the long-term mean. Irrigation has become a justified and essential agrotechnical measure that minimizes the damage caused by water deficit during critical plant growth stages and ensures high yields with good quality. In this paper two vegetation seasons (2006 and 2007) with quite different weather conditions for maize production were analysed in order to examine the importance of irrigation in terms of yield increase, irrigation water use efficiency (IWUE), irrigation efficiency (IE) and irrigation water use index (IWUI) in years favourable (2006) or too dry (2007) for maize production. The yield surpluses achieved with irrigation ranged from 8.54 t ha−1 to 9.62 t ha−1 in the average crop year (2006) and from 8.43 t ha−1 to 10.7 t ha−1 in the dry year (2007), depending on the irrigation method. In the dry year the values of IWUE where higher than in the average year (6.16 and 13.75 kg ha−1/mm, respectively, averaged over the hybrids).
Authors:V. Guberac, S. Maric, M. Bede, J. Kovacevic, G. Drezner, A. Lalic, M. Josipovic, M. Krizmanic, T. Juric and D. Kis
The aim of this research was to examine influence of sowing rate on grain yield of four new winter wheat cultivars, taking in account their genetic characters. Statistical analysis of the obtained results showed that the sowing rate influence on the grain yield was not statistically significant. On the other hand, various sowing rates had highly significant influence on the ear number per a unit area. The largest number of ears was achieved by the sowing rate of 700 germinable seeds/m
).Difference in grain yield between examined cultivars was highly significant (P<0.01) while the difference in number of ears per a unit area was significant (P<0.05). The highest average yield and highest number of ears in the two-year period were achieved by the cultivar AG 5.12 (8.56 t/ha and 770 ears/m
).Since a satisfactory and statistically significant grain yield was achieved, even with a lower sowing rate, both during and in the average of the two year research, the author’s advice wheat producers to apply the above mentioned. In this way total production costs would be decreased to a lower rate.