The successful production of soybeans is largely dependent on the sowing time, because every sowing outside the optimal time contributes significantly to yield losses. This field study aimed to evaluate the effects of sowing time (optimal—April 5; late—April 27) on the quantitative and quality traits of three soybean genotypes (Galina—0 maturity group; Sava—I maturity group; and Rubin—II maturity group) under dryland conditions in Vojvodina Province (Serbia) during 2017 and 2018. The genotype Sava had higher yield in climatic-unfavorable 2017, while Rubin had a higher yield in climatic-favorable 2018. The yields significantly decreased when the soybeans were sown in late April due to reductions in the number of pods per plant, seed weight per plant, and 1000-seed weight. The reduction in yield components was likely due to the accelerated senescence of plants and the negative effect of high temperature and low precipitation during the seed filling stage. Accordingly, the various sowing times and properly chosen genotypes provide a better utilization of soil and water resources. A proper genotype selection and sowing time can contribute to a high yield. At the same time, the protein and oil contents can be altered by the sowing time, especially under water stress during the reproductive stage.

The main nitrogen (N) sources in soybean production originate from soil fixing bacteria Bradyrhizobium spp. and from mineralization of soil organic N. These sources of N are often not sufficient to cover the N needs of the soybean. The present two-year field study aimed to evaluate the effects of soybean genotypes (Valjevka and Galina) and rates of starter fertilizer N (0, 30, 60, and 90 kg ha⁻¹) on quantitative and qualitative parameters and on rain use efficiency (RUE) under contrasting weather conditions in the Pannonian region of Serbia. A field study conducted during two different growing seasons: first year with unfavorable weather conditions and second year with favorable weather conditions. As expected, the quantitative parameters, oil content, and RUE were higher in the year with favorable growing season, the second one. According to measured parameters, the genotype Valjevka performed higher yield potential as compared to the genotype Galina. The highest values of quantitative parameters and RUE were recorded at 60 kg N ha⁻¹, protein content at 90 kg N ha⁻¹ and oil content 0 kg N ha⁻¹ (control). This study suggests that proper genotype selection and application of 60 kg N ha⁻¹ as a starter dose with rhizobial inoculation could contribute to the high yield, while protein could be altered by N amount, independently on genotype.

Fusarium graminearum as the main causal agent of Fusarium head blight (FHB) and its ability to produce trichothecenes was investigated by molecular techniques. A total of 37 strains isolated from the wheat, harvested in Serbia in 2005, 2008 and 2015, and previously designated by morphological observation as F. graminearum, were used for trichothecene genotypes characterization. The strains were identified using the species-specific primer set FG16R/FG16F while genotypic characterization was done using specific TRI13 and TRI3 sequences of the trichothecene gene clusters. The PCR assays identified all strains as species of F. graminearum sensu stricto with the DON/15-ADON genotype. The quantification of the mycotoxin (DON) was performed using the biochemical assay. The high levels of DON (>20,000 µg kg⁻¹) were recorded in all of the strains from 2005, four strains from 2008 and two strains from 2015. Weather data of the investigated seasons, showed that the optimal temperature, frequent rains and high relative humidity (RH) was very favourable for the development of F. graminearum, affecting the DON biosynthesis.

The main aim of this research was to study the effect of two sowing times (early and late) on Fusarium and fumonisin contamination and some yield component traits of two maize hybrids from the FAO maturity groups 500 (ZP 560) and 600 (ZP 666) within a two-year growing season (2016–2017). F. verticillioides and F. subglutinans have been identified as Fusarium ear rot (FER) pathogens and potential producers of B-type fumonisins (FBs), with F. verticillioides as the predominant Fusarium species in both years. The incidence of F. verticillioides and FB levels were affected by sowing time and maize hybridity. With early sowing and the mid-maturity hybrid ZP 560, F. verticillioides and FB contamination were lower than with late sowing and the late-maturity hybrid ZP 666. Yield parameters also differed significantly between sowing time and maize hybrid treatments. Early sowing increased ear length (EL), number of grains per ear (NGE), grain weight per ear (GWE), and grain yield per hectare (GY). The late-maturity hybrid ZP 666 had higher yield component traits and GY than the mid-maturity hybrid ZP 560. EL, GWE, thousand-grain weight (TGW), and GY were affected by year. Interactions between sowing times and maize hybrids were highly significant (p ≤ 0.01) for FB level, GWE, and GY. The obtained results indicate the importance of applying early sowing to achieve high maize grain yields with lower contamination by F. verticillioides and FBs. Although mid-maturity hybrid ZP 560 and late-maturity hybrid ZP 666 showed significant differences in terms of levels of F. verticillioides and FB contamination, both were susceptible to F. verticillioides, with high FB levels. These results should be useful to breeders of maize hybrids to create genotypes more resistant to these fungal contaminants.

The objective of our study was to investigate the diversity of individual parameters of quality of grass-legume mixture silages harvested in two stages of crop utilization and the impact of the interaction of studied factors on the quality. Legumes as an important source of protein are very difficult to ensilage. However, in mixture with grasses their fermentable characteristics are improved. During the growth and development of plants, their chemical composition changes, hence their ability and suitability for ensiling also changes. In regard to the studied factors, the phase of exploitation had a highly significant impact on almost all quality parameters in both years. By delaying the harvest period, dry matter content in silage has significantly increased and the level of crude protein and NH3-N decreased. In regard to the content of lactic acid, the studied silages fall into category of good quality silages. Its content in the first year ranged from 24.3-31.5 in the early harvest stage and from 27.9-36.2 g kg-1 DM at the late harvest stage, and in the second year from 27.4 to 31.4 in the early harvest stage and from 28.2- 31.9 g kg-1 DM at the stage of late harvest. According to the content of acetic and butyric acids, studied silages can also be considered as silages of good quality.

This experiment aimed at determining the effect of farmyard manure (FYM)applicationon a natural pasturein Western Serbia, with a 30 t ha-1treatment incomparison to control (no fertilizer added) during two years (2012-2014).The FYMwas applied in the autumn of 2012 and the trial plots were harvested twice a year.Dry matter (DM) yield and forage quality - content of crude protein (CP),nonprotein N (%CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) andnet energy for lactation(NEL), were estimated for each production year. Treatmentwith manure gave a higher DM yield compared to control plots in bothexperimental years (5.91 t ha-1 vs. 3.01 t ha-1 in 2013, and 2.76 vs. 2.03 t ha-1 in2014). As expected,the yield in the second cuts of both years was much lower thanin the first cuts. The FYM application did not affect chemical composition and netenergy concentration of forages, whereas significant effects of different cuts werefound, but were inconsistent between the first and second experimental year. Ingeneral, it can be concluded that application of FYM did not have a significanteffect on forage quality ina permanent grassland, whereas chemical compositionwas significantly affected by different cuts and experimental years. Based on theresults, a grassland may have a good DM yield response if FYM is used as afertilizer, while the effect on forage qualitymay be much weaker.