Marko Josipović

Wheat and maize yield variations in the Brod-Posavina area

In general, wheat and maize yields in the Brod-Posavina County (BPC) were about 15% lower (10-year means 1981–1990) in comparison with their yields in the region. Wheat yield variations in the region among the years were higher in comparison with maize yield. For example, the highest yield of wheat and maize were higher than the lowest yield for 61% and 34%, respectively. Analogic comparison for Slav. Brod and N. Gradiska municipalities were 78% and 41% (wheat), as well as 41% and 24% (maize), respectively. In the last 8-year period, mean wheat yields in the region were for 17% lower and maize yield for 4% higher in comparison with mean yields of 80ies. These differences in level of BPC were 10% lower and 12% higher, for wheat and maize, respectively. We presume that low or absence effects of tile drainage because of their inadequate servicing could be expalantion for wheat yield decreasing. The lower yields of wheat are mainly in connection with oversupplies of water. However, low maize yields are in connection with water shortage and the higher air-temperatures. Low supplies of P and K are additional factors of low yields of field crops in the hydromorhic soils of the BPC.

Response of maize to fertilization with KCl on gleysol of Sava valley area

Five maize ( Zea mays 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 2 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 2 O/ha every third year and a choice of tolerant hybrids.

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...

Influences of irrigation and fertilization on soybean properties and nitrogen leaching

Influences of irrigation rates and N fertilization on soybean grain yield and N leaching were tested under field conditions on Osijek, during the growing seasons 2001, 2003 and 2005 (A). The irrigation started on level of 80% field water capacity, A1 (FWC) and at level of 65% FWC, A2 and irrigate up to FWC, and non-irrigated, A3. Increased rates of N: 0, B1; 100, B2 and 200 kg N ha −1 , B3 were applied. The experiment was conducted by split-plot method. Ebermeier’s lysimeters (open type: 80 × 80 × 10 cm) were conducted for collecting leachate for measuring nitrogen leaching. The soybean grain yield showed statistical very significant differences in growing season, irrigation and interaction of growing season and irrigation. Mean leaching NO 3 -N varied from 0.32 kg N ha −1 to 7.88 kg N ha −1 in year 2001, while were greater in year 2005 and varied form 2.41 kg N ha −1 to 23.71 kg N ha −1 .

Influences of irrigation and N fertilization on maize ( Zea mays L. ) properties

Water quantity and the application period are highly significant for achieving high yield. Also, the best results can be obtained with the proper amount of macro and micro nutrients, especially nitrogen. However, nitrogen is ecologically a very sensitive element. The climatic factors and irrigation have a great effect on the efficiency of fertilization. Therefore, the objective of this study was to examine the effects of supplemental irrigation and nitrogen fertilization on grain maize yield and yield components. The maize grain yield and yield components showed statistical differences between the 2000 growing season (10.64 t ha-1) and 2002 (12.14 t ha-1). Irrigation variant A1 (keeping soil water from 80 to 100% FWC) gave the best results in yield and in all the researched components. Medium (B2) and higher nitrogen level (B3) also gave the best results in the research except grain/ear ratio which had the best results with B1 (100 kg N ha-1). The highest level of irrigation (80-100% FWC) and nitrogen level (200 kg N ha-1) did not give statistically significant higher yield and yield components. Applying 150 kg N ha-1 in the year 2000 also proved environmentally suitable quantity of nitrogen on the researched soil since the higher level of N (B3) did not increase the yield.

Influence of sowing date on the occurrence of fusarium head blight on wheat — A phytosanitary food safety problem

Fusarium head blight is a worldwide disease of small grain cereals, including wheat, which has a negative impact on grain yields and quality. Six winter wheat cultivars were sowing during three years (2000-2002) on 25th September, 15th October and 1st November at the location of Osijek. The grain infection with Fusarium species was determined after harvesting in laboratory using deep-frezing method. The least infection intensity was observed on all cultivars sowed at the end of September, although some cultivars (Zitarka, Srpanjka, Demetra) sowed at mid October did not achived significant differences in grain infection in comparison to those sowed at the end of September. Respecting all three research years and sowing dates, the cv. Zitarka had the smallest number of infected grains

Potassium availability in hydromorphic soils of eastern Croatia

By our study 480 soil profiles were analysed which covered area of 31227 ha and they were divided in six soil types. This area was hydromeliorated in the period from 1978 to 1989. Plant availavle K was determined by Ammonium-Lactate method. One third of tested area (9989 ha or 32%) is low and moderate supplied (less than 10 mg K2O/100g). Especially a high frequency (near 50% or 4629 ha) of low K status was found on hypogley. We recommend an once application of 1000 kg K2O/ha for soils characterizing very low in K (less than 5 mg K2O/100g: about 7% of tested area) and 500 kg K2O/ha for soils low in K from 5.1 to 10.0 mg K2O/100g (about 25%). Amelorative fertilization with KCl up to 2670 kg K2O/ha for K-deficient drained gleysol were once applied. Maize yields (3-year means) were increased from 1.93 t/ha to 7.64 t/ha or four-fold. At the same time, a considerable improvement of K and Mg relationship in plants was observed.

Responses of grain composition traits to high plant density in irrigated maize hybrids

The objective of this study was to examine the effects of supplemental irrigation and higher plant density on grain composition traits of ten maize hybrids. The experiment was grown in Osijek (Eastern Croatia) in 2002, 2003, 2004 on eutric cambisol, and consisted of factorial combination of two irrigation levels (non-irrigated and irrigated), two plant densities (standard – 57140 and high – 63492 plants ha-1, respectively), and ten commercial maize hybrids of FAO maturity groups 500-700. A self-moving sprinkler was used for irrigation to maintain water content in soil from 60% to 100% of field water capacity. Irrigation consistently affected grain yield across the years, but not the composition traits. Higher density did not affect grain traits except for water content, protein and oil concentration in 2002. Averaged across ten hybrids and two irrigations levels in 2002, higher density decreased protein concentration from 8.92% to 8.76%, and oil concentration from 3.71% to 3.65%.

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.

Evaluation of Different Soil Water Potential by Field Capacity Threshold in Combination with a Triggered Irrigation Module

Irrigation efficiency improvement requires optimization of its parameters like irrigation scheduling, threshold and amount of water usage. If these parameters are not satisfactorily optimized, negative consequences for the plantsoil system can occur with decreased yield and hence economic viability of the agricultural production. Numerical modelling represents an efficient, i.e. simple and fast method for optimizing and testing different irrigation scenarios. In this study HYDRUS-1D model assuming single- and dual- porosity systems was used to evaluate a triggered irrigation module for irrigation scheduling in maize/soybean cropping trials. Irrigation treatment consisted of two irrigation regimes (A2 = 60–100% field capacity (FC) and A3 = 80–100% FC) and control plot (A1) without irrigation. The model showed a very good fit to the measured data with satisfactory model efficiency values of 0.77, 0.69, and 0.93 (single-porosity model) and 0.84, 0.67, and 0.92 (dual-porosity model) for A1, A2, and A3 plots, respectively. The single-porosity model gave a slightly better fit in the irrigated plots while the dual-porosity model gave better performance in the control plot. This inconsistency between the two approaches is due to the manual irrigation triggering and uncertainty in field data timing collection. Using the triggered irrigation module provided more irrigation events during maize and soybean crop rotation and consequently increased cumulative amounts of irrigated water. However, that increase resulted in more water available in the root zone during high evapotranspiration period. The HYDRUS code can be used to optimize irrigation threshold values further by assuming different scenarios (e.g. different irrigation threshold or scheduling) or a different crop.