Danijel Jug

Influence of different soil tillage systems on yield of maize

Maize is one of the most important crops in Croatia, especially for the Panonian part - Slavonia and Baranja region, which is producing, in average, 30% of total maize production in the country (Kovacevic and Josipovic, 1998). The practice is mainly conventional, based on standard soil tillage including ploughing as primary tillage operation, which is the most expensive, slow, with high demands for fuel and labour. Also, it can be ecologically unfavourable and non-sustainable. Meanwhile, in the latest twenty years the knowledge about soil tillage in Croatia and its vicinity (Birkas and Gyuricza, 2000) has been changed, as in many countries in the world, toward simplification, reduced, rational tillage, which was the subject of research by Croatian authors, for instance Zugec (1984), Culjat and Tabakovic (1991) and Jug et al. (2006). Diskharrowing or chiselling, as a primary tillage operation, was not researched thoroughly enough, especially in the light of other reduced tillage systems, such as no-till, where equipment price of special no-till planters and heavier tractors can be limit for average farmers, especially in the changing climate conditions, as emphasised by Dobo et al. (2006). The scope of this paper was to optimise soil tillage for maize in longer period of time.

Reduced soil tillage systems for crop rotations improving nutritional value of grain crops

The trial for winter wheat ( Triticum aestivum L. ) or spring barley ( Hordeum vulgaris L. ) in rotation with maize ( Zea mais L. ) on lessive-pseudogley in semiarid to semihumid climate of Eastern Croatia was set up during years 1996–1999 with five soil tillage systems: PL) Conventional tillage based on ploughing; PD) Conventional tillage after diskharrowing for previous crop in preceding season; DP) Diskharrowing after conventional tillage for previous crop in preceding season; DD) Continuous diskharrowing, and CD) Chiselling and diskharrowing. During first and second season (1996/97 and 1997/98), recorded winter wheat grain yields were not different, with PL having the highest and DD the lowest yield. Maize showed next differences in first season: PL=PD>CH=DD=DP, and in second season PD=PL=DP=CH>DD. In 1999, spring barley replaced winter wheat, and yields were: PL>DP>PD>CD>DD. Maize yields recorded were: PL>PD>DP>CH>DD. The grain yield results, together with hectoliter mass and mass of 1000 grains, sup...

Effects of conventional and reduced tillage systems in winter wheat — soybean crop rotation on crops biomass development

Croatian Baranja region contains soils with highly quality crop production properties, but the knowledge of the effects of reduced tillage systems is lacking. Our investigations were conducted under field conditions at Knezevo site chernozem in four replications. They included four soil tillage systems (CT: conventional tillage, with ploughing up to the 30 cm as a primary tillage; DS: diskharrowing up to the 15 cm; CH: chiselling up to the 30 cm + diskharrowing; NT: no-till seed drilling), both for winter wheat ( Triticum aestivum L. )-soybean ( Glycine max L. ) in crop rotation during three growing seasons (2002–2004). All measured crop properties were strongly affected by different seasons, especially with the season of 2003 with extreme drought. Crop biomass in five growth stages for winter wheat showed that at the beginning DS and CH had stronger growth than CT and NT, but differences vanished toward final stages. Winter wheat grain yield achieved by reduced tillage systems was in average either highe...

Winter wheat and soybean zinc uptake in different soil tillage systems

Winter wheat and soybean were grown under field conditions on chernozem soil of Knezevo, Croatia, for four years (from 2002 to 2005) in three applied soil tillage treatments: a) CT — conventional soil tillage, based on mouldboard ploughing, b) DH — soil tillage based on diskharrowing instead of ploughing; and c) NT — no-tillage. Both crops showed decreasing concentration of Zn within the plant tissue as a result of the soil tillage reduction in the order CT>DH>NT, presumably due to the limited roots growth in lesser disturbed soil at DHand NT treatments. Winter wheat recorded generally lower than optimal Zn concentrations and higher P:Zn ratios at reduced soil tillage treatments, as a result of lower Zn uptake. The recommendation for the winter wheat production by reduced soil tillage is additional Zn fertilization, whose exact amounts and way of application shall follow further research.

Tillage and nitrogen effects on winter wheat yield and selected soil physical properties on hypogley of Eastern Croatia

The field research was conducted on hypogley in Vrbanja, Croatia, during four growing seasons from 1992/1993 to 1995/1996. They included five soil tillage systems and three nitrogen fertilization levels in four replications for winter wheat (Triticum aestivum L.) after soybeans (Glycine max L.) as a preceding crop. Tillage treatments were: PL=conventional tillage (ploughing to 20 cm depth, diskharrowing and standard sowing); DS=diskharrowing and standard sowing; MC=tillage by multitiller and chisel, standard sowing; RS=soil tillage and sowing by RAU-Rotosem; PR=ploughing to the depth of 20 cm + RS. Nitrogen fertilization treatments were 140 (N1), 170 (N2) and 200 kg N ha−1 (N3). Wheat grain yields effects by tillage were as follows: 6.00 (PL), 5.79 (DS), 5.65 (MC), 5.61 (RS) and 5.90 t ha−1 (PR). Significant differences of yields were found only in the first year of testing. Nitrogen fertilization resulted by non-significant differences of yields as follows: 5.56 t ha−1 (N1), 5.85 t ha−1 (N2) and 5.96 t ha−1 (N3). The conclusion is that under certain environmental conditions it is possible to apply reduced soil tillage and moderate N fertilization.

Soil tillage impacts on nutritional status of wheat

Soybean were grown under field conditions on chernozem soil for four growing seasons (from 2002 to 2005). Three treatment of soil tillage were applied as follows: a) conventional tillage, b) reduced tillage (diskharrowing instead of ploughing) and c) no-till (zero-tillage). In general, the characteristics of growing season (the factor „year“) were more influencing factor of soybean nutritional status (aerial part in stage of full-developed pods) in comparison with the soil tillage. In our study, low influences of applied soil tillage treatments on nutritional status of soybean were found because significant differences on soybean composition were found only for four (Cu, Cr, Sr and Ba) from total 20 analysed elements. For example, conventional tillage resulted by the higher plant Cu (by 15% and 18% in comparison with DH and NT, respectively), and the lower plant Sr (by 12% and 16%, respectively) and Ba (by 26% and 23%, respectively), while under DH conditions by 22% lower plant Cr was found. Main nutrient...

The effect of year, genetic and morphologic specificity at the kernel mass, chemical composition and vigour of the maize seed

Oil rape is a valuable fodder because in early spring and late autumn it produces green forage used for the nutrition of domestic animals. It has been replacing sunflower and soy in colder and wetter regions. It is additionally advantageous because it leaves behind more nitrogen in soil, which is beneficial to other plants in plant rotation. There are some possible ways for the fixation of nitrogen in soil and they are as follows: by the means of oil rape straw ; by relatively long roots ; by the action of nitrogen bacteria, which perform the nitrogen synthesis within their root system, which is the case in some leguminous plants. Oil seed rape is expected to be wider used in crop rotation of West and Middle Europe, Croatia included. Due to this various sorts have been introduced and potential positive impacts have been studied in order to boost the process. This paper presents information on barley and wheat yield in case when they were sown after oil seed rape and corn. The aim of the research is to determine the presence of positive impacts upon the soil with special attention paid to a potential increase of nitrogen content after oil seed rape was grown. The preceding crops had statistically significant effect. Rape yield was significantly higher compared to the one with corn as preceding crops. Very similar results were obtained in 2007.The maize hybrids seed from three different FAO groups (FAO 400, FAO 500 and FAO 600) in four fractions (KO, KP, SO and SP) produced in two climatically different years (extremely dry 2000 and extremely wet 2001) had been different in quality and chemical composition. The effects of year, genetic specifity and seed fraction at the kernel mass, chemical composition (starch, proteins, cellulose, oil and moisture content) and seed vigour have been evaluated. The influence of agroecological conditions during two production years have been exposed at seed chemical composition and vigour indicators (cold test – CT and bulk seed electrical conductivity - EC). The genetic specificity and seed fraction had significant influence at all tested indices, with the exception of the influence of the fraction at the starch content

The influence of the temperature, genetic specificity and seed size at early growth and development of the maize in controlled conditions

The optimal planting terms, which contain favorable conditions for emergence and early growth, are one of the most important preconditions for achieving high grain yields. During this period, the most important environmental factors are temperature and soil moisture, which have a key role for optimal conditions needed for the young plants genotype potential expression. Beside genetic specificities which are preconditioning plants growth and development, the seed size is one of the very important biological factors which has strong influence at faster sprouting and intensive growth within the heterotrophic stage, when seed reserves have the key role for supplying young plant with the nutrients. The tolerance of the maize hybrids at suboptimal temperatures which can frequently occur in early spring has been observed by Szundy et al. (2005) through the number of days to emergence and individual dry shoot mass. According to Pommel et al. (1995), plants developed from greater seed had higher leaf area if compared with plants from smaller seed. Gilbert et al. (1995) concluded that the dry weight of plants shoot and root is positively correlated with the seed size. Batistella et al. (2002) found out in their research that there were significant differences between hybrids and seed category and their influence at shoot and root length, together with shoot dry weight in favor of larger seed fractions. After Grzesiak (2001) smaller ratio of shoot and root length is indicating higher hybrid resistance on the induced stress. The aim of this research was to determine the influence of the temperature, genetic specificity and seed size fractions at phenologic and physiologic features of the maize in early growth.

Dynamic chloroplast pigments concentration in leaves of soybean ( Glycine max [L.] Merr.) under reduced tillage

The objectives of this experiment were to determine the chloroplast pigments dynamics of soybean leaves during the growth stages under different tillage systems, which can be a major factor limiting yield of soybean. The greatest differences between the photosynthetic productivity parameters of the investigated soybean were determined from reproductive stages (R2 and R3 – 4). The chlorophyll a, chlorophyll a/b and carotenoids content under CT, DH and NT were greater in the reproductive stages (R2 and R3 – 4) than in the early stages (V3 – 4 and R1). The concentration dynamics of chlorophyll b and chlorophyll a/b was very similar in all growth stages and under all tillage systems in the 2-yr average. The increased drought stress in 2003 was likely critical in the observed lower seed yields in 2003. The yield of soybean was significantly lower under NT than CT and DH treatments in both years. The relationship between the soybean yield and chloroplast pigments concentration is strongly influenced by external factors. In the 2-yr average the soybean yield was considerably affected by the years and tillage systems. Statistical analysis showed a very significant relationship between chlorophyll pigments content, but photosynthetic parameters investigated did not correlate with soybean yield.