engleski

Investigation of rational soil tillage for maize (Zea mais L.) in eastern Croatia

Large scale production and investigations with reduced soil tillage for some crops in the eastern parts of Croatia in the latest past decades have shown some possibilities in rationalisation of soil tillage for the main arable crops, especially for cereals and maize. Among a some of the new organised experiments with maize in the mentioned area, one has been carried out on lessive-pseudogley soil type, in the middle part of Slavonia, results of which are the main scope of this paper. The experiment has been started in 1997, on the arable land of agricultural enterprise PP “Orahovica”, unit “Čačinci”, representing mainly a great part of lessive-pseudogley soil type of that agricultural area. The trial has been established as more-year stationary type, with two (or three) crops (winter wheat, possibly spring barley, and maize) in rotation, for every year. The following tillage treatments have been practised: 1 – Conventional, standard soil tillage based on shallow stubble field diskharrowing after harvesting of w. wheat in summer, ploughing (30-35 cm) in autumn and in spring diskharrowing, classical seed-bed preparation by combination seed-harrow (spike tooth harrow + rotary harrow) and sowing ; 2A – Conventional tillage, like at variant 1, in one, and only tillage by diskharrowing and seed-bed preparation in the second year of production (i.e. shallow stubble field diskharrowing in summer, autumn and spring), and alternately in the following years ; 2B – Only tillage by diskharrowing in one, like at var. 2A in the second year, and conventional tillage, like at var. 1, in the second year, and further on the same way (namely, 2A and 2B variants are alternatives) ; 3 – Only tillage by diskharrowing continuously (shallow stubble field diskharrowing in summer, autumn and spring) and seed-bed preparation on common way ; 4 – Tillage based on diskharrowing and seed-bed preparation, like at var. 3, but combined by loosening or chisel ploughing of plowlayer only (up to 35 cm) by Shakearator (McConnel, 40 cm spacing between subsoiling chisels) in 1996/97 and 1997/98, or by Pseudo (chisel) plough (pitch 15-21 cm, working depth up to 40 cm) in 1998/99. Uniform fertilisation for the whole experimental field was based on 200 kg N, 100 kg P2O5 and 150 kg K2O/ha. The hybrid OSSK 382 (FAO 410) was planted for 65000 plants/ha on 13th May 1997 and 1st May 1998. The basic plot size was 720 m2 (18x40 m), the trial was as monofactorial, carried out as randomised plots in four replications. Climatically, the investigated years were completely different, i.e. the first year (1997) was very favourable for maize production, with high grain yields, then the second (1998) was characterised by a few stresses (drought periods combined by high temperatures) and with the average grain yields. In 1997 year, the grain yields were as follows: var. 1=10.56 ; var. 2A=10.55 ; var. 2B=8.16 ; var. 3=8.38 ; and var. 4=8.98 t/ha. The differences among variants 2B, 3 and 4 comparing to standard tillage (var. 1) were highly significant. In the second year (1998) the grain yields were: var. 1=8.48 ; var. 2A=8.85 ; var. 2B=8.17 ; var. 3=7.47 ; and var. 4=7.66 t/ha. Only var. 3, comparing to standard treatment, had statistically significant lower yield. Surface loosening of the main root zone of plowlayer appeared to be a good substitute for ploughing. Conclusion, indeed temporarily, could be that according to the grain yields, the ploughing represents the high yielding treatment, but that the other tillage practices reserve more attention, too. Namely, energetically, economically and organisationally, some investigated rational tillage treatments offer much more favourable advantages then the yield alone, although the continuous diskharrowing showed itself as the lowest yielding practice.

reduced tillage ; maize ; standard conventional tillage ; diskharrowing ; diskharrowing and chisel ploughing

nije evidentirano