engleski

Soil compaction under different soil tillages for maize in eastern Croatia

The maize production in eastern Croatia is based on conventional soil tillage which includes ploughing (30-35 cm) and standard seedbed preparation (diskharrowing, harrowing, seeding), which is the most yielding tillage technology, although the most expensive and with the strongest environmental influence, especially at the surface, within the ploughing layer. But, the latest investigations and wide farming practices in eastern Croatia show the possibility of lower tillage impact through the reduced soil tillage techniques, which still maintain acceptable grain yield level. The experimental site "Čačinci" have been established as a monofactorial trial, with randomised plots in blocks within four replications, and with basic plot area of 720 m2 (18x40 m). in 1996, as a stationary experiment on lessive-pseudogley soil type, which is the dominant soil type of "Čačinci" farm, PP "Orahovica" agricultural enterprise. The maize hybrid OSSK 382 has been sown after winter wheat in 1997, 1998 and 1999, with the next soil tillage treatments: 1) Standard, conventional soil tillage based on ploughing (30-35 cm) and diskharrowing, then classical sowing ; 2A) Standard ploughing and diskharrowing, like at variant 1 in one year, then only diskharrowing (10-15 cm) in the next year, and alternately in the following years ; 2B) Diskharrowing only (10-15 cm) in one year, and standard ploughing and diskharrowing, like at var. 1, in the next year, and alternately in the following years (2A and 2B are alternatives) ; 3) Diskharrowing only (10-15 cm), continuously ; and 4) Tillage based on diskharrowing and seed-bed preparation, like at var. 3, but combined with loosening of chisel ploughing of plough-layer only (up to 30 cm) by Shakearator (McConnel's type, 40 cm spacing between subsoiling chisels) in 1997 and 1998, or by Pseudo (chisel) plough (pitch 15-21 cm, working depth up to 40 cm) in 1999. The soil resistance has been sampled by mechanical cone- penetrometer with spring on five different depths (5, 10, 15, 20 and 25 cm) per each plot. The undisturbed soil samples have been taken at two depths (7-12 and 20-25 cm). Both samplings were carried out during July 1999. The standard tillage (var.1) soil resistance average showed 854 kPa, whereas other tillage variants gave 645, 862, 906 and 707 kPa for variants 2A, 2B, 3 and 4, respectively, with no significant difference toward conventional tillage. Similar results have been shown on bulk density, where was no significant difference between var. 1 (1.44 g cm-3) and other variants (1.43, 1.41, 1.48 and 1.49 g cm-3, for var. 2A, 2B, 3 and 4, respectively). Porosity averages had similar relationships (Pvar. 1 = 46.2, Pvar. 2A = 47.2, Pvar. 2B = 47.4, Pvar. 3 = 44.8, and Pvar. 4 = 44.2 %). In spite of similar soil properties, unfavourable weather conditions influenced strongly yields under shallower tillage systems, thus pointing out some disadvantages for reduced tillage practices on lessive- pseudogley soil type in northeastern Croatia.

standard conventional tillage ; diskharrowing ; diskharrowing and chisel ploughing ; soil resistance ; soil water holding capacity ; porosity

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