Search

The purpose of the study was to trace the after-effect of soil and leaf herbicides applied in maize on the next crop in rotation - wheat. In a 4-year period were carried out field experiments. The efficacy and selectivity of herbicides in maize were traced. Visual observations of plants of wheat were conducted during various phenological phases of the crop: germination, first leaf displayed (BBCH-11), two leaves displayed (BBCH-12), tillering (BBCH-20), lactic maturity (BBCH-77). Manifestations of phytotoxicity on the wheat plants were not established. After-effect of the herbicides was traced and the formation of major quantitative traits: plant height, length of classes, number of classes, number of grains in the class and weight of grain in the class. By variance analysis of pooled data were analyzed signs and evidenced the differences compared to the untreated control. The differences between the variatns with treatment and the control are essential. This confirms the visual assessments about the lack of negative after-effect of Laudis OD, Lumax 538 SC, Elumis, Gardoprim plus Gold 500 SC, Wing P, Stellar, Casper 55 VG and Merlin flex, applied in maize, on the next crop in rotation. [ABSTRACT FROM AUTHOR]

Basic agrochemical characteristics were studied in maize grown under different variants of nitrogen fertilization. The maize hybrid P0216 of Pioneer Company was studied, grown under irrigation conditions, following the conventional adopted technology in our country. The hybrid is characterized by high productivity and drought resistance. The trial was set by the block-plot method with a plot size of 21 m2. Nitrogen (2.4 kg N/ha) was applied in the following variants: 1. Untreated control; 2. NH4NO3 - pre-sowing application of the whole rate; 3. NH4NO3 - split application: ½ presowing and ½ at 5th leaf; 4. NH4NO3 - 1/3 pre-sowing application, 1/3 - at 5th leaf and 1/3 - at tasseling stage; 5. NH4NO3 - ¼ pre-sowing application, ¼ - at 5th leaf, ¼ - at 12th leaf and ¼ - at tasseling stage; 6. CO(NH2)2 - presowing application of the whole rate; 7. CO(NH2)2 - ½ pre-sowing and ½ at 10th leaf; 8. CO(NH2)2 - ½ pre-sowing and NH4NO3 - ½ at 10th leaf; 9. CO(NH2)2 - ½ pre-sowing and NH4NO3 - ½ at tasseling stage. Export of nutrients and their use efficiency per production unit are important agrochemical indicators for maize. Their values vary according to the genotype, soil and climatic conditions, the predecessor and fertilization. Nitrogen export varies greatly depending on the fertilization rate and phosphorus and potassium export - depending on the genotype and climatic conditions during the year. [ABSTRACT FROM AUTHOR]

Three hybrids of maize of Pioneеr Company (P9241, P9900 and P0023) grown at different plant densities (40000, 46000, 56000, 69000 number per ha) were studied in the experimental field of Agricultural University of Plovdiv in 2015 and 2016. The purpose of this study was to trace the influence of sowing density of maize hybrids on growth and yield. The experiments were carried out by split-plots method. The experimental areas were fertilized with a nitrogen fertilizer rate of 240 kg/ha - ½ CO(NH2)2, applied in the 5-6 leaf stage of the plant and ½ NH4NO3, applied into the 10th leaf stage. A hybrid P9900 has the highest plants at the end of vegetation. There was no significant difference between variants with plant densities - from 279.4 cm (40000 plants/ha) to 284.4 cm (56000 plants/ha). Height of plants of hybrid P9241 was the smallest - 260.5 cm at a sowing density of 40000 plants/ha. The highest yield between 3 hybrids was obtained at a sowing density of 69000 plants per ha. Hybrid P9241 showed yield of 13800 kg/ha, while hybrid P9900 - 14257 kg/ha. [ABSTRACT FROM AUTHOR]

The effect of the soil herbicide isoxaflutole on the growth and development of new corn hybrids in controlled conditions was studied. Conducted assays confirmed that tested hybrids exhibit different sensitivity to herbicide treatment, expressed as a decrease of chlorophyll or increase of anthocyanin content. The lowest content of chlorophylls was determined for hybrid P0216 and the highest anthocyanin levels were observed for hybrid P9241. Present investigation was performed for evaluation the toxic effect of the herbicide and demonstrated that plant pigment content can be used as a marker for abiotic stress. This study could be very useful for practical applications as a preliminary test for phytotoxicity and/or sensitivity of different crops or model plants to herbicides. [ABSTRACT FROM AUTHOR]