This study evaluated the effects of the application of microbial inoculants (N-fixing Klebsiella planticola and Enterobacter spp.), two rates of composite mineral fertilizers, and their combination on microbial biomass carbon (MBC), dehydrogenase (DHA), and proteinase activity (PTA) in Lessivated Cambisol and yield-related properties of maize and wheat grains in a two-year trial. Unfertilized soil was used as a control variant. MBC was measured using the chloroform fumigation-extraction method, DHA was determined spectrophotometrically by measuring the intensity of the formed red-colored triphenyl formazan, while PTA was determined using a titration method by measuring the degree of gelatine decomposition. In grain samples, P was determined spectrophotometrically, K—by flame emission photometry, N—on an elemental carbon/nitrogen/sulfur (CNS) analyzer, and crude proteins—by calculation of N content. Measuring both crops’ yield was carried out at the end of the vegetation. The results indicated that mineral fertilizers are not, in general, negative for soil microbiota when used in the context of sustainable agriculture without monoculture. There is a significant increase in the values of soil MBC, DHA, and PTA in the variants with combined application of bacterial inoculants and lower rates of mineral fertilizers. The highest values of these parameters were determined in the period with a better distribution of precipitation during the vegetation period of the year. The mentioned combination also resulted in a higher grain yield of maize and wheat comparing to the application of lower rates of the NPK nutrients solely. The combined application of high rates of mineral fertilizers and bacterial inoculants resulted in significantly increased N, P, K, and protein content in the grains of crops, and the same applied to yield. Concluding, studied bacterial inoculants can be used to specify the replacement of nitrogen fertilizers, stimulating the microbial biomass and enzyme activity in the soil, helping to ensure that the supply of nutrients contributing to an optimized yield of crops is maintained.

The biological activity (contact and contact-digestive toxicity, repellent and fumigant effects, effect on the insect’s development and life cycle parameters) of industrial hemp (Cannabis sativa L.) ethanolic extract was assessed against Plodia interpunctella, the most destructive storage pest of sunflower. Additionally, the study aimed to examine the phytotoxic activity of the extract in order to assess its potential as a sunflower grain protectant. Phytotoxicity assessment was based on the effect on germination energy and seed germination and the activity of antioxidative enzymes, enzymes of the polyphenolic metabolism, and the intensity of lipid peroxidation in sunflower seedlings. The antioxidant capacity and content of phenolic compounds (total phenolics and total tannins) were also measured in seedlings. In the experiments, 70% ethanolic extract of dried flowering buds of industrial hemp (variety Helena) was applied at 0.5%, 1.0% and 2.0% concentrations directly on sunflower seeds. Ethanol solution (70%) was the control. The hemp extract (1% and 2%) revealed medium repellence for P. interpunctella larvae (L_3–4) while at 2% concentration it caused 42.5% larval mortality after 72 h. Moreover, the insect’s development was prolonged and fecundity significantly reduced in hemp treatments. The extract did not exhibit fumigant activity. Germination energy and germination of sunflower seeds were stimulated in treatment with 2% hemp extract, while most biochemical parameters of the seedlings were not significantly affected by the hemp extract.

Mycotoxins in maize represent a great threat to human health. For this reason, novel technics such as ozone treatment are used to reduce the content of maize mycotoxins. However, there is little knowledge about the effect of ozone treatment on maize quality parameters. This study investigated the changes in Fusarium and Aspergillus mycotoxins and the changes in fatty acids during the ozone treatment of maize samples. Sixteen maize hybrids were visually tested for the naturally occurring ear rot severity and treated with three different concentrations of ozone (40, 70, and 85 mg/L). Mycotoxin content in maize samples was determined using a high-performance liquid chromatography (HPLC) system, whereas dominant fatty acids were determined using gas chromatography coupled with a flame ionization detector (GC-FID). Ozone treatments could be successfully applied to reduce the content of mycotoxins in maize below the detection limit. Ozone treatments increased the content of monounsaturated fatty acids (MUFAs) and decreased the content of polyunsaturated fatty acids (PUFAs), i.e., linoleic acid (36.7% in relation to the lowest applied ozone concentration), which negatively affected the nutritional value of maize.

Plant density, the number of plants per unit area, is an important factor in maize production. Plant density exhibits high variability and depends on a number of factors, i.e., the length of the growing period of the hybrid, the morphological characteristics of the plant, the amount and distribution of precipitation during the growing season, the reserve of winter moisture in the soil, the level of soil fertility, the time of sowing, agronomic management practices, and biomass and yield. The objective of this paper was to determine the agronomic optimal plant density for maize in calcareous soil in the semiarid conditions of the South Pannonian Basin. Field experiments were conducted at the experimental field—IFVCNS (two locations: Rimski Šančevi and Srbobran) to evaluate four plant densities (55,000; 65,000; 75,000; and 85,000 plants ha⁻¹). The experimental sites “Rimski Šančevi” and “Srbobran” are located in the typical chernozem zone of the southern part of the Pannonian Basin. On average for all hybrids, the grain yield followed a second-degree polynomial model in response to the increasing planting density, with the highest value at plant density (PD2: 65,000 plants ha⁻¹). To achieve maximum yield, the optimal planting density for corn hybrids of the FAO 200 group should be 57,600 plants ha⁻¹, for the FAO 300 group 64,300 plants ha⁻¹, for the FAO 400 group 68,700 plants ha⁻¹, for the FAO 500 group 66,800 plants ha⁻¹, and for the FAO 600 group 63,500 plants ha⁻¹. “Which–Won–Where” biplot showed that the hybrid H24 from FAO 600 group was the highest yielding in all of the environments. Hybrid H17 from the same FAO group was the most stable across all of the environments. Selected hybrids may further be studied for planting density and nutritional requirements for getting maximum yield. By introducing new maize hybrids with higher genetic yield potential and better agronomic management practices, modern mechanization and agricultural techniques allowed to increase planting densities.

The effects of plant growth promoting (PGP) bacteria on soybean growth and yield were tested in field conditions using four treatments: (A) Bradyrhizobium japonicum strain 526, combined with cell-free supernatants (CFS) of Bacillus sp. strain Q10 and Pseudomonas chlororaphis strain Q16; (B) B. japonicum 526 + Bacillus sp. Q10; (C) B. japonicum 526 + P. chlororaphis Q16 and (D) commercial fertilizer containing B. japonicum, which served as a control. The average values of dry weight per nodule and shoot dry weight had the maximum values in the B treatment. In dry shoots collected at the flowering stage, nitrogen and carbon content was similar across all treatments, while that of sulphur decreased in treatment A. Relative to the control (D), all treatments showed positive effects on pods number and grain mass per plant, with the best results yielded by treatment A. Nitrogen and sulphur content in grain were significantly higher in treatment C, whereas maximum carbon content was measured in treatment B. In the control, it was obtained the yield of 4,000 kgha^-1, which was in accordance with data reported by the seed producer for the same growing conditions (the maximum value). The yields of 4,229, as well as 4,286 and 4,400 kg ha^-1 were measured for variants C, B and A, respectively, which were statistically significant higher (5.73 to 10%) than the commercial fertilizer (D). The improvement in soybean growth and yield in the field trial achieved by addition of PGP strains Bacillus sp. Q10 and P. chlororaphis Q16 to B. japonicum 526 can result in more productive agricultural practices.

The objectives of this study were to determine the effects of fertilization system, nitrate (NO₃)– nitrogen (N) distribution along soil profile, and their interaction on corn yield. The study was conducted at the experimental field of Institute of Field and Vegetable Crops in Novi Sad (Serbia) during 2001–2004. Corn monoculture included four fertilization variants: control (Ø), nitrogen–phosphorus–potassium (NPK) mineral fertilizers, mineral fertilizer + corn stalks (NPK + S), and mineral fertilizers + manure (NPK + M). The greatest yield was found in the variant NPK + M (9.25 t ha⁻¹). Path coefficients showed that greatest direct positive effects on corn yield were exhibited by NO₃-N levels at soil depths of 60–90 cm and 30–60 cm. The path analysis showed that winter precipitation (WP) had a direct negative effect on yield performance. However, the effect of the downward movement of NO₃-N from the topsoil to deeper soil layers of WP on yield was positive.