Productivity of common wheat (Triticum aestivum L.) grown after various predecessors and nitrogen fertilization rates

M. Gerdzhikova*

Department of Plant Growing, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 12 December 2016; accepted for publication 20 February 2017)

Abstract. During the period 2008-2011 the influence of the predecessors wintering peas, spring peas, sunflower and common wheat and different levels of nitrogen fertilization: 0 (N0), 40 (N40), 80 (N80), 120 (N120) kg/ha after legumes and 0 (N0), 60 (N60), 120 (N120), 180 (N180) kg/ha after the other predecessors on the productivity of common wheat was studied on the experimental field of the Department of Plant Growing, Trakia University. It was found that with cultivation of common wheat without fertilization after legume predecessors higher yields by 9.4 % were obtained compared to the other predecessors. The highest yields were obtained at fertilization with the highest nitrogen rates: after legume predecessors 4069.8 kg/ha grain; after sunflower and wheat 3853.2 kg/ha of grain. The strongest influence on the productivity of common wheat had nitrogen fertilization as a factor with 79.80 %. The yield of wheat grain correlates very well with the level of nitrogen fertilization and can be determined approximately by regression equations based on the quantity of nitrogen as an independent variable.

Hot-water treatment of gladiolus cormels for control of corm-borne fungal diseases

S. Bistrichanov1, T. Vatchev2, Z. Avramov1*

1University of Forestry, 10 Kliment Ohridski, 1797 Sofia, Bulgaria
2Institute of Soil Science, Agrotechnologies and Plant Protection, 35 Panayot Volov, 2230 Kostinbrod, Bulgaria

(Manuscript received 18 May 2016; accepted for publication 23 January 2017)

Abstract. A hot-water treatment was used successfully to obtain pathogen-free planting stock from various plants to control some diseases including gladiolus. The objective of this study was to evaluate the effect of hot-water treatments in terms of damaging gladiolus, concerning sprouting and leading to crop loses. Cormels of two gladiolus cultivars, Oscar and Amsterdam, were used for each treatment (temperature x time period) and were immersed in water baths with hot water at 20 ̊C (as control), 45 ̊C, 50 ̊C, 55 ̊C and 60 ̊C for different treatment periods 10, 20 and 30 min and were planted in pots (d10cm) filled with sterile nutrient substrate (peat:soil:perlite in ratio 3:1:0.5). Three replicate pots each containing 10 cormels were used per treatment. The results showed that the increase of the temperature and the extension of exposition duration reduced significantly the percentage of the sprouting plants from both cultivars – more than 80% at 55 ̊C/20min, and Oscar was more resistant to this treatment regime. For phytosanitary purposes two treatment options were considered as non- damaging – 45 ̊C for 30min or 50 ̊C for 20min, wherein the resulting plants showed approximately 90% sprouting. It was concluded that for successful disease control specific hot-water treatment regimes should be established for every particular gladiolus cultivar.

Phytosanitary status and yield of kamut (Triticum turgidum polonicum L.) grown in organic and biodynamic farming

V. Maneva*, D. Atanasova, T. Nedelcheva

Institute of Agriculture, 1 Industrialna, 8400 Karnobat, Bulgaria
(Manuscript received 30 June 2016; accepted for publication 27 October 2016)

Abstract. During the period of 2013 – 2015 the influence of farming types (organic and biodinamic) on the phytosanitary status and yield of kamut was studied. Kamut is resistant to diseases and they are not a problem for growing it in an organic and biodynamic way. In both kinds of farming single numbers of five types of pests on kamut were recorded. Two of them were from Order Homoptera (Sitobion avenae L. and Rhopalosiphum maidis (Fitch)) and three from Hemiptera (Philaenus spumarius (L.), Eurygaster integriceps Put. and Aelia acuminata L.).The species diversity of the weeds was greater in biodynamic farming. Kamut yield from biodynamic farming was proven to exceed the organic one. The strength of effect of the type of farming factor was 83.57%.

Comparative analysis of plane geometric parameters of various types of cow milking parlors

D. Georgiev*

Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 5 May 2016; accepted for publication 11 September 2016)

Abstract. Geometric planning parameters of milking parlors of similar capacity and different arrangement of animals on cow platform were analyzed. Indicator (K) was calculated to reflect the ratio of length (L) to width (W) of the cow platform. It can be used by designers and farmers for practical purposes to select the type or capacity of a cow milking parlor when reconstruction an existing facility (at particular planning parameters available). This study discusses alternative solutions for milking parlors of various configurations (tandem, herringbone, and parallel type parlors) of capacity from 2×5 to 2×10 cows. The following planning parameters were investigated: absolute and relative (per milking stall) floorage area of milking parlors with various configuration (without entrance/exittrafficlanes)atrespectivecapacity;ratioindicator(К)ofthemaindimensions(lengthandwidth)ofthemilkingzoneasguidance forselectionofa milking parlor at specified conditions (reconstruction of existing facility). For each alternative the dimensions (length and width) at respective capacity and configuration were taken, and only the milking zone without animal entrance and exist lanes was considered. Conclusions drawn from the results are aimed at minimizing the relative area of milking stalls in the design of milking parlors at specified technological conditions.

Effect of fluorescence on the technological characteristics of cocoons at different cooking temperatures

M. Panayotov*

Department of Animal science-Non-ruminant and other animals, Faculty of Agriculture, Trakia Univercity, 6000, Stara Zagora, Bulgaria (Manuscript received 5 May 2016; accepted for publication 11 August 2016)

Abstract. The subject of research are Bombyx mori L. cocoons, differentiated by the nature of their fluorescent radiation. In each fluorescent group 2 subgroups were formed prepared for unreeling through cooking at 80 and 90°C for 5 min. To account for the effect of fluorescence at various cooking temperature levels the basic technological traits signs of the silk filament and cocoons have been defined and analysed: total length of the silk filament (m), nonbroken filament length (m, %), raw silk pesentage (%) and reelability (%). It was found that fluorescence of cocoons has statistically significant (p≤0.01- 0.001) effect on the phenotypic manifestation of the technological traits. Within the two cooking temperature levels, the yellow fluorescent cocoons demonstrate higher values at 80 °C, and violet ones at 90°C. The better technological qualities and the lower cooking temperature in the yellow fluorescent cocoons give reason to believe that their use is economically more profitable for the silk reeling industry compared with violet fluorescent cocoons.

Biochemical and chemical investigations of pikeperch fingerlings (Sander Lucioperca L.) after wintering

A. Ivanova*, R. Atanasova

Institute of Fisheries and Aquaculture, 248 Vasil Levski, 4003 Plovdiv, Bulgaria (Manuscript received 14 September 2016; accepted for publication 13 October 2016)

Abstract. The purpose of the present study was to investigate some basic biochemical and chemical parameters of pikeperch (Sander lucioperca L.) yearlings reared in ponds after wintering. The investigation has been carried out in the Institute of Fisheries and Aquaculture, Plovdiv. The fish included in the study were randomly selected from one pond, with area of 0.40 ha. Blood samples were collected from 10 pikeperches with average weight from 80 to 100 g. Blood biochemical parameters were individually analysed. For hemoglobin determination, blood was anticoagulated with sodium citrate. Samples for body tissue analysis (without the head and viscera) were collected from 4 fish, autoclaved and used for analysis of water content, % (drying at 105 оС, 24 h; Bulgarian State Standard – SR ISO 5984), protein content, % (Kjeldahl method, Bulgarian State Standard – SR ISO 5983 semi-automated DK 6 digester unit and UDK 132 distillation system, Velp Scientifica), fats (%) by the method of Smidt-Boudzynski Ratzlaff and ash (%) by burning in a muffle furnace at 550 oС, BSS – SR ISO 6496. The average blood serum total protein was 66.1±0.12 g.l-1, blood glucose concentration was 92.8±3.42 mg.100 ml-1 (5.15 mmol.l-1) and average hemoglobin content was 44.7±0.33 g.l-1. The average protein content in analysed fish samples was 16.65±0.23 %. Protein content was the highest among studied dry matter components, followed by the ash (1.97±0.06 %) and fat content (0.84±0.03 %). The levels of blood serum total protein, blood glucose and hemoglobin content as well as body composition parameters – water, protein, fat and ash of pikeperch fingerlings (Sander lucioperca L.) after wintering reflect the specific equilibrium of plastic and energy substances after the winter period, with no deviations from the reference ranges.

Efficacy and timing of some new products against pear psylla (Cacopsylla pyri L.) (Hemiptera: Psyllidae): II. Spirodiclofen

V. Arnaudov*

Institute of Fruit Growing, 12 Ostromila, 4004 Plovdiv, Bulgaria
(Manuscript received 30 June 2016; accepted for publication 7 September 2016)

Abstract. The effectiveness of spirodiclofen (Envidor® 240 SC) in the control of pear psylla (Cacopsylla pyri L.) on pear trees was evaluated in field experiments,carriedoutincommercialpearorchardinthevillageDinknearPlovdiv (Bulgaria)during2014–2015.Theefficacyofspirodiclofen(Envidor240 SC ® at a dose of 600 and 800 ml/hl) in controlling this pest was compared to that of abamectin (Vertimec 018 EC at a dose 150 ml/hl). Each one of the insecticides was applied only once in the presence of predominantly “yellow” eggs and the first hatched larvae from the second generation of C. pyri. Аpplied only once at a dose of 800 ml/hl, spirodiclofen (Envidor® 240 SC) effectively reduces populations of the pest, achieving from 92.6 to 96.4% efficacy 21 days after treatment (DAT). Envidor 240 SC applied at a lower dose of 600 ml/hl had a slightly worse effect, achieving from 90.0 to 93.1% efficacy 21 DAT. The effectiveness of spirotetramat at both doses after only one application was very high and insignificantly different. In comparison with the reference insecticide (abamectin) the efficacy of spirodiclofen was slightly weaker in the first two weeks after treatment and insignificantly different at the end of the third week after the treatment (the total reduction of larvae ranged between 82.4 – 87.4% 3 DAT and 90.0 – 96.4% 21 DAT in the spirodiclofen treated plots, while in the abamectin treated plot it ranged between 92.9 – 96.5% 3 DAT and 94.0 – 98.7% 21 DAT. Spirodiclofen (Envidor® 240 SC), both tested doses gave similar results, which are significantly weaker in the first days after treatment, but significant enough and improved in time. This active substance, in contrast to abamectin, demonstrated a slow initial activity and a longer persistence. Spirodiclofen can be considered as a reliable tool to control of C. pyri and possible alternative to abamectin to prevent the risk of resistance in pest populations.

Grain combines productivity according to various unloading methods – in the field and at the edge of the field

N. Delchev1*, K. Trendafilov2, G. Tihanov1, Y. Stoyanov1

1Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Machine Engineering, Faculty of Engineering and Technologies – Yambol, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 3 July 2016; accepted for publication 23 August 2016)

Abstract. Grain tank unloading is usually done at a standstill. In some cases the combine has to leave the processed strip and to unload in a vehicle located outside the field. The publication analyses the reasons for unloading grain tanks by leaving the processed strip and the impact of this type of unloading on the combine productivity compared to unloading the grain tank in the field itself. A study has been performed in Bulgarian farms using different ways of unloading and the results of time measured for unloading grain tanks in and at the end of the field have been given when harvesting various agricultural crops. The combine productivity when unloading in the field and at the edge of the field has been compared. It has been determined that when unloading at the edge of the field the productivity is approximately 11% lower than the productivity during unloading at a standstill in the field.

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Influence of the year characteristics and the different fertilization levels on the structural elements of wheat yield

V. Kuneva1*, R. Bazitov2, A. Stoyanova3

1Department of Mathematics, Informatics and Physics, Faculty of Economics, Аgricultural University, Plovdiv, Bulgaria 2Agricultural Institute, 6000 Stara Zagora, Bulgaria
3Department of of Plant Production, Faculty of Agriculture, Thracian University, 6000 Stara Zagora, Bulgaria

(Manuscript received 1 May 2016; accepted for publication 24 June 2016)

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 “ear- bearing stems” (96%).

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Efficacy and timing of some new products against pear psylla (Cacopsylla pyri L.) (Hemiptera: Psyllidae): I. Spirotetramat

V. Arnaudov*

Institute of Fruit Growing, 12 Ostromila, 4004 Plovdiv, Bulgaria
(Manuscript received 30 June 2016; accepted for publication 7 September 2016)

Abstract. Pear psylla (Cacopsylla pyri L.) (Hemiptera: Psyllidae) is one of the key insect pests in pear orchards of Bulgaria. Field trials to evaluate the efficacy and timing of spirotetramat (Movento 100 SC ®) against C. pyri were carried out in a commercial pear orchard in the village Dink near Plovdiv (Bulgaria) in 2014 and 2015. Three periods of application were tested against the second summer generation of C. pyri: (А) in the presence of predominantly “white” eggs, (B) in the presence of predominantly “yellow” eggs and the first hatched larvae, and (C) in the presence of about 15 – 30% hatched larvae and nymphs. In all three periods of application spirotetramat (Movento 100 SC) applied at a dose of 150 ml/hl effectively reduced the population of pear psylla after only once application. Movento 100 SC applied in the presence of predominantly “white” eggs (A) and in the presence of predominantly “yellow” eggs and the first hatched larvae (B) demonstrated better efficacy than in the presence of about 15 – 30% hatched larvae and nymphs (C). The efficacy of spirotetramat (Movento100 SC) in the first two periods of application (A) and (B) was similar and insignificantly different from that of the reference insecticide abamectin (Vertimec 18 EC, applied at a dose of 150 ml/hl), but significantly higher than the efficacy of spirotetramat, applied in period (C). The total reduction of larvae at three week post-treatment was at the level of 94.6 – 98.7% for the period (A) and (B), 89.7 – 93.3% for the period (C) and 94.0 – 98.7% for the reference insecticide – abamectin. The high efficacy observed in different terms of application and long persistence makes this product extremely valuable in controlling populations of C. pyri.

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