Influence of the year characteristics and the different fertilization levels on the structural elements of wheat yield Abstract. The aim of the development is (through two-way dispersion analysis -ANOVA) to study the impact of the factors "year characteristics" and "fertilization levels" on the separate biometric indicators for wheat: ear length (cm), ear-bearing stems (cm), number of grains per ear (num.), grain weight per ear (g) and mass of 1000 grains (g). Data for the yield and its structural elements were used. They were obtained through a field experiment conducted in the period 2009 -2011, on a meadow-cinnamon soil in the experimental field at Agricultural Institute -Stara Zagora. With high degree of reliability the impact of the examined factors and their interaction on the following indicators was statistically proven: length of wheat-ear (cm), ear-bearing stems (cm), number of grains per ear (N), grain weight per ear (g), mass of 1000 grains (g). The strongest impact on the given factors has the factor "fertilization levels" for the indicator "earbearing stems" (96%).Keywords: wheat, fertilization levels, two-way dispersion analysis (ANOVA) AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 8, No 3, pp , 2016 DOI: 10.15547/ast.2016 Introduction experimental field of the Agricultural institute, town of Stara Zagora. The wheat, Sadovo 1 variety, was grown in the second and fourth year, in four-field sowing rotation with corn for seed-grain under Mineral fertilization of the field crops is one of the basic agroirrigation. The soil in the experimental area is of a meadowtechnical sources for increasing and stabilizing the yield, for cinnamon type. It is characterized with humus horizon, moderately sustainable economic growth of the farms, for good ecological developed. It is poor in nitrogen (31.3 -38.1 mg/kg soil), poor in condition of the agricultural lands (Gerganov, 2009). Mineral absorbable phosphorus (3.1 -4.3 mg/kg soil) and well supplied with fertilization of wheat in our country is about 30% of the production absorbable potassium (42.3 -48.1 mg/100 g soil). Humus content in expenses (Arkadiev and Valeva, 1995; Gramatikov and Koteva, the upper layer is 1.18 -2.11%. 1995). It has approximately the same percentage for the yieldThe experiment was made through the block method, with a formation (Gramatikov and Koteva, 1995). Mineral fertilization also 2 size of the crop parcel 20 m . We have established in other helps for maintenance and improvement of soil fertility (Кoteva, publications of ours that the consequence of the different soil 1993). There is a lot of research for determining the optimum manipulations for the corn does not have significant influence on the parameters of the basic agro-technical factors and their impact on structural elements of the wheat yield. That is why here we consider productivity of wheat in different regions in our country. Wheat is only the impact of the "fertilization" factor. In the field experiment we characterized with a great agro-ecological diversity (Borisova and ...

The aim of this study was to establish the efficacy of herbicide combinations between Tender EC and Titus + Magneto SL, and Wing P and Mistral Opti applied in a field of maize under the conditions of mixed irrigation. The study has been carried out with maize cultivated on meadow-cinnamon soil at the experimental field of the Agricultural Institute – Stara Zagora for the period 2014-2016. The research was conducted with a mid-grade hybrid corn LG35.62 with the same background of fertilization and irrigation with the following variants: 1) Control (without herbicides); 2) Wing P – 4000 ml/ha and Mistral Opti – 210 ml/ha, and 3) Tender EC – 1500 ml/ha and a mixture of Titus – 40 g/ha + Magnet SL – 1200 ml/ha. Increasе of maize yield by 41.6% (on average) in comparison with the control variant and by 28.9% compared to the variant Wing P and Mistral Opti was found.

The study was conducted in the experimental field of the Agricultural Institute in Stara Zagora under irrigation conditions on meadowcinnamon soil with maize for grain, medium late hybrid LG 35.36 with sowing density -7000 plants per decare. The еxperiment includes the following four options of fertilization: opt.1non-fertilized sentinel plot, opt. 2fertilization with N10 kg/da active substance, opt.3 fertilization with N15 kg/da active substance and opt. 4fertilization with N 20 kg/da active substance. With an increase in the fertilization rate, the content of crude protein in the maize grain also increases too, with the largest increase of 20.3% compared to the unfertilized sentinel plot being the option with the highest fertilizer rate -N20 kg/da , followed by the option with N15 kg/da active substance per decare.The content of crude fiber in the maize grain with the increasing of fertilization rate decreases by 14-30% compared to the unfertilized sentinel plot, with the least content in the option with rate -N10 kg/da active substance.The content of metabolizable energy is the highest -14.94 MJ/kg in variants 2 and 3 -N10 kg/da and N15 kg/da. The FUM for all variants was 1.64 FUM/kg DM The FUG for the N20 kg/da variant is 1.78 FUG/kg DM, and for all other nitrogen fertilization levels it is 1.79 FUG/kg DM.The highest content of protein digestible in the intestine is expected in the option with the highest level of nitrogen fertilization-20 kg active substance per decare -123 g/kg DM, and for the other optionsthe values are as follows: 116 g/kg DM; 119 g/kg DM and 121 g/kg DM for a fertilization level of 0, 10 and 15 kg of active substance of nitrogen per decare.

In the experimental field of the Agricultural Institute, Stara Zagora, on meadow -cinnamon type soil, an experiment with a medium -late maize hybrid Antalya 450 from FAO in case of disturbed irrigation regime was conducted. It was found that the optimally irrigated variant with three irrigations yields an average yield of 1607 kg/dry biomass, which is 20.0% higher than the yield obtained from the non-irrigation variant. With the cancellation of the second irrigation the yield of dry mass decreases by 7.6% compared to the optimal variant, and with the cancellation of the first irrigation the losses of dry biomass reach respectively 12.3% compared to the control variant. The effect of the application of disturbed irrigation regime is highest when canceling the first watering irrigation (K = 0.93) and the lowest values are for the variant with cancellation of the second irrigation (K = 0.57).

The aim of the present study is to determine the impact of the disturbed irrigation regime on the yield and the chemical composition of Sudan grass, grown as a second crop. To accomplish this goal, a trial was conducted in the experimental field of the Agricultural Institute - Stara Zagora with Sudan grass on meadow-cinnamon soil under irrigated conditions. The following variants have been studied: 1 - without irrigation (control variant); variant 2 - optimal irrigation, 75-80% of field capacity (FC); variant 3 - irrigation as in variant 2, but with the removal of the first watering; variant 4 - irrigation as variant 2, but with the removal of the second irrigation; variant 5 - irrigation as variant 2, but with the removal of the third watering. It was found that when growing Sudan grass as a second crop with optimal irrigation and disturbed irrigation regime done by canceling successive watering, the highest yield of dry biomass is obtained with optimal irrigation including three irrigations. Its yield increased by 24.2% compared to the control treatment. Irrigation of Sudan grass with only the second and the third irrigation in a row, without the first irrigation provided, leads to the lowest yield of dry biomass - 11290 kg / ha. Among the chemical composition indicators, the most significant change is observed in the content of the crude fat, followed by that of the crude fiber and crude protein, depending on the method of growing Sudan grass (with or without irrigation).