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The purpose of this study is to determine the impact of controlled permanent water deficiency and three levels of fertilization on earliness and total yield of tomatoes, greenhouse production using different mathematical approaches. In order to evaluate the morphological manifestations, the early harvest and the total yield under the influence of different irrigation and nutritional regimes, a tomatoes variety "Vitelio" was used. The irrigation is done with a drip irrigation system. Against the background of the same fertilizing rates in the variants with different irrigation norms there is a decrease in the early stage with an increase of the irrigation norms. A high correlation between plant height and total yield, with correlation coefficient (r = 0.899) and between sheet count and total yield r = 0.824 was found. There was a negative correlation between the first and third harvests and the total yield, respectively with correlation coefficients r = -0.724 and r = -0.704. The nature of the linear relationship between plant height and total yield is determined by the coefficient R2 = 0.8. Based on a two-factor analysis, it was found that irrigation regime had a dominant influence on the two parameters considered: height and yield, which was statistically proven with a very high degree of confidence (p ≤ 0.001).

The action of some foliar herbicides and herbicide combinations for control of common wheat (Triticum aestivum L.) weeds was studied. To that end against the background of soil applied Stomp 330EK New at a dose of 5 l/ha the herbicides Axial 050EK, Granstar 75DF, Derby Super WG, Sekator OD, Lintur 70WG, and the tank mixtures of Axial with the other herbicides applied in the tillering phenophase of the crop were studied. The species composition and density of weeds was assessed using the quantitative method prior to treatment and after herbicide treatment on days 5, 15 and 30, by constant metering. The herbicide Lintur 70WG and its combination with Axial 050EK had the fastest initial effect. The highest herbicidal effect (99.5%) against annual monocotyledon and dicotyledon weeds showed the combination of Derby Super WG 33 g/ha + Axial 050EK - 900 ml/ha. Very good was the effect of the other herbicidal mixtures between anti-broadleaf herbicides and the graminaceous herbicide Axial 050. All applied herbicides and herbicide mixtures showed a very good after-action on weeds.

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 ...