Effects of soil tillage (CTconventional, SS-subsoiling, CH-chiselling, DH-disk-harrowing and NT-no-till) and nitrogen rate (reduced N1, optimal N2 and luxury N3) on yield and yield components of maize and winter wheat in two different agricultural subregions of Croatia (Magadenovac and Cacinci site), were studied in the years 2013–2014 as part of a long-term experiment. Maize yield and yield components were influenced by site properties, tillage and nitrogen treatments. The highest yields and yield components were recorded at the Magadenovac site with N2 and N3. The lowest values of the yield and yield components of maize were recorded on NT and were significantly lower than CT, SS, CH and DH, among which no significant differences were recorded. Winter wheat yield and yield components were affected by site properties and nitrogen rates while soil tillage treatments only had an influence on grain and straw yield and plant height. Winter wheat achieved maximum yield and yield components on a N3 and N2 and at the Magadenovac site. Winter wheat grain yield decreased in the following order: SS > DH > CH > NT > CT. The obtained results indicate the importance of optimal nitrogen fertilization and the possibility of the implementation of conservation tillage for maize and winter wheat production in different agroecological conditions.

Biochar, a carbon-rich material, is highlighted to improve soil fertility, simultaneously mitigating climate change by carbon sequestration. Combined with mineral fertilizer, it can increase weediness, the major source of yield loss in agricultural production. Research with biochar was conducted in Eastern Croatia in 2016, with the aim to investigate the influence of biochar and mineral fertilizer on weed infestation and winter wheat yield. Field experiments were set up as a split-plot where biochar (B) was the main factor and fertilization was the sub factor. The main treatments were: B0 (control without biochar), B1-5 t ha⁻¹, B2-10 t ha⁻¹ and B3-15 t ha⁻¹. Fertilization sublevels were F0) without fertilizer and F1) optimal dose of fertilizer. Weediness was determined by counting and measuring aboveground biomass. The treatments with the greatest effect on weediness were B3 and F1 in the winter wheat tillering stage. In the winter wheat ripening stage, treatment B3 obtained the highest weediness and F1 significantly reduced weed density. Biochar treatment B3 increased winter wheat yield by 77% in relation to the control. The application of biochar combined with fertilization affected the level of weediness depending on agroecological conditions, but with a significant increase in yield.

Maize is the most represented grain crop on the world’s arable land. It is mostly grown using standard sowing at an inter-row distance of 70 cm. However, growing in two rows (double-row sowing) is increasingly common today. The aim of this research was to determine the influence of different spatial distributions of the same population of maize plants on the yield of maize grains in a larger range of the FAO maize hybrid maturing group. The experiment lasted 5 years and was set up at two locations in Jakšić (Požeško-Slavonia County) and Lužani (Brodsko-Posavina County). Maize sowing with standard sowing was carried out with a PSK OLT seed drill with an inter-row spacing of 70 cm, while double-row sowing was carried out with a MaterMacc Twin Row-2 seed drill in two rows spaced 22 cm apart in a zigzag arrangement and 48 cm apart between adjacent sowing furrows. In the experiment, a total of three types of maize hybrids were used: H1-Kashmir (FAO 390 maturing group), H2-Kapitolis (FAO 400 maturing group) and H3-Konfites (FAO 450 maturing group). With standard maize sowing, an average set of plants was achieved: 71,946 plants ha⁻¹ (Kashmir), 71,714 plants ha⁻¹ (Kapitolis) and 72,205 plants ha⁻¹ (Konfites), while the double-row sowing achieved a set of plants of 72,166 plants ha⁻¹, 72,104 plants ha⁻¹ and 72,576 plants ha⁻¹. The two-row sowing of the hybrid Kapitolis and Konfites recorded a statistically significant higher set of maize plants. The yield of maize grains in all three types of the hybrid was statistically and significantly higher by 943 kg ha⁻¹ using two-row sowing, and the highest yield was achieved by the Kashmir hybrid (13,406 kg ha⁻¹).

The three–year trials of the impact of the planting technology on the maize yield were carried out at the trial sites Jakšić and Tenja. The KWS Intelligens and KWS Kollegas hybrids were used in the research, planted at a standard row spacing of 70 cm, and in the twin rows with a spacing of 48 × 22 cm. In 2020, the highest average grain yield at the site Jakšić in standard planting, with the KWS Intelligens hybrid, was 12.064 t ha–1, and in the twin row planting an increase in yield of +4.17% was recorded. The KWS Kollegas hybrid had the highest difference in grain yield between a standard and twin row planting in 2021 of +7.52%, in favor of the twin row. At the site Tenja, slightly higher grain yields were recorded in all three years of research. The major difference in yield was recorded in 2020 with the hybrid KWS Kollegas, of +8.22%, or 1.115 t more grain, when planting in the twin rows in comparison with a standard planting. The statistical tests indicate that planting in the twin rows at both trial sites obtained statistically significant results in all three years of research concerning the grain yield ha–1, grain weight per ear, and grain moisture content.

In this paper, the results of maize grain yield (kg ha-1) sown in standard and twin row technology are shown. The research has been conducted at the experimental field of Faculty of Agrobiotechnical Sciences, near location of Tenja...