Influence of biomanipulation on the living communities and the water quality in the Strezhevo hydroecosystem, R. Macedonia

  1. R. Nastova*, V. Kostov, N. Gjorgovska, V. Levkov

Institute of Animal Science, “Ss Cyril and Methodius” University of Skopje, Bul. Ilinden 92a, 1000 Skopje, Republic of Macedonia

(Manuscript received 21 June 2017; accepted for publication 16 January 2018)

Abstract. The aim of this study was to investigate the influence of the biomanipulation on the living communities and water quality in the Strezhevo hydroecosystem, Republic of Macedonia in which a problem with increase of primary organic production has occurred. The biomanipulatory intervention in water bodies is used to prevent the development of macrophyte vegetation. It is achieved by direct influence on the increased development of phytoplanktonic production and macrophytes by gradual and controlled introduction of grass carp (Ctenopharyngodon idella). The study was conducted in the period June-September 2012 in two earthen ponds (A and B), situated in Strezhevo Lake with 100 specimens of grass carp/pond with average individual mass of 4 kg and age of 3–5 years. The following were monitored: water – temperature (oC), pH, dissolved oxygen (O2 mg/l) and saturation (%); grass carp – length (mm), weight (kg), Fulton and Clark coefficients of fattening, consumption of added in ponds fresh vegetable mass (kg), consisting of Ceratophyllum demersum (hornwort) (95%) and Potamogeton pusillus (small pondweed) (5%). Based on the results obtained, the meliorative ability of this species with high density of the stock was evaluated as very favourable. At optimal temperature, oxygen regime and pH conditions of water, this herbivore fish species consumed the present macrophytic vegetation very intensively, and in the case of its absence, also the additional share of fresh herbal mass, showing certain selectivity towards particular water vegetation species. Thus, grass carp maintains an optimal composition of the macrophytic communities in the hydroecosystem.

Effect of nutmeg extract supplementation on some productive traits and economic efficiency of common carp (Cyprinus carpio L.) cultivated in recirculation system

  1. Zhelyazkov*, S. Stoyanova, I. Sirakov, K. Velichkova, Y. Staykov


Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University,

6000 Stara Zagora, Bulgaria

(Manuscript received 21 December 2017; accepted for publication 16 February 2018)


Abstract. The aim of the present study was to evaluate the effect of a dietary nutmeg extract supplement on the survival rate, growth performance, feed conversion ratio and economic efficiency of common carp (Cyprinus carpio L.) reared in a recirculation system. Thirty-two carps were allotted into two experimental variants, each of them comprising two replications with 8 fish in a group. The average initial live weight of carps from the control group (CG) and experimental group (EG) was 866.56±113.99g and 868.50±111.18g, respectively (P>0.05). Fish were reared in concrete tanks with efficient volume of 0.8m3, elements of the recirculation system. They were fed pelleted carp feed with 25% crude protein produced by “Top mix” company, with pellet size of 6mm. The feed of fish from the EG was supplemented with 1% powdered nutmeg extract after lubricating the pellets with 5ml sunflower oil per 100g feed. Control carps received the same amount of sunflower oil-lubricated feed. The daily ration of fish from both replications was 1.8% of their live weight. The experiment duration was 45 days. The initial and final live weights were determined by individual weighing. By the end of the experiment, there was a tendency towards statistically insignificant higher average live weight in fish supplemented with 1% nutmeg extract – 986.44±125.91g vs 964.94±92.04g in non-supplemented controls (P>0.05). The survival rate of carps from both control and experimental group replications was 100%. The average individual weight gain of carps from the two EG replications (supplemented with 1% nutmeg extract) was 117.94±31.24g which was higher than that of controls by 16.58% but the differences were not statistically significant (P>0.05). At the end of the trial, the analysis of consumed feed amount showed that feed conversion ratio in the group supplemented with 1% nutmeg extract was 3.05±0.78, i.e. by 23.28% lower than that of control carps (P>0.05). The group that received 1% nutmeg extract exhibited better economic conversion ratio (2.71), by 4.06% lower than that of the non-supplemented group.

Economic efficiency of fattening on different genotypes slow-growing and fast-growing broiler chickens

  1. Oblakova*, Y. Popova, P. Hristakieva, N. Mincheva, M. Lalev


Agricultural Institute, 6000 Stara Zagora, Bulgaria

(Manuscript received 21 June 2017; accepted for publication 16 January 2018)


Abstract. In the present study six lines from the National Gene Pool (Bulgaria) were used, four of which – line NG (New Hampshire G), line E (Barred Plymouth Rock), line Ss (Sussex) and line F (NG x Red Rhode Island) as maternal forms in the crossing schedule and two sire lines, meat type – line L (White Plymouth Rock) and line M (Cornish), for production of slow-growing broilers. The effect of genotype on meat quality traits was studied with 5 groups of 150 unsexed day-old chicks from each genotype, and after the manifestation of sexual dimorphism – male and female chickens at 70 and 84 days of age. In valuation on revenues and costs of the fattening of the compared groups current prices at the time of the experiment were used. Cost of feed is determined according to the actual feed. In determining the economic efficiency of fattening, three variants of sales prices per kg of meat – 3.60 BGN/kg, 4.65 BGN/kg and 5.30 BGN/ kg have been analysed. The rate of profitability is a synthetic indicator for economic efficiency, calculated by the formula: NP = (Profitability / Production costs) * 100, %. Feed expenses for experimental group I were lowered by 22.8%, while in groups II, III, and IV- by 13.48%, 9.42% and 9.05%, respectively, compared to group V, which registered the highest consumption of feed in the amount of 5.52 BGN. The share of feed expenses in group I was 53.45% of total expenses, and in groups II, III, and IV group they were 59.88%, 56.30%, 57.50%, and 56.87%, respectively. The highest profits per the accepted sale prices were observed in group V- 10.71 BGN, 13.68 BGN and 15.52 BGN, respectively, followed by group IV with 8.56 BGN, 10.92 BGN, and 12.38 BGN, respectively.  At a level of sale prices of 3.60 BGN/kg a positive value of profitability was registered for the fattening of chickens from group V – 16.03%. In all other groups, the profitability norm was negative. At a level of sale prices of 4.65 BGN/kg, the highest profitability was observed in the chickens of group V – 48.21%, followed by group IV – 25.37%, while the lowest cost efficiency was in group III – 4.24%. In the variant with a sale price of 5.30 BGN/kg, the profitability norm was the highest in group V – 68.14%, followed by group IV – 42.13% and group II – 40.98%, while the lowest level was in group III – 18.21%.

Evaluation of some technological properties of Caucasian ram wool

D. Pamukova1*, G. Staykova2, N. Stancheva2, D. Panayotov1

1Department of Animal Science – Ruminant Animals and Dairy Science, Faculty of Agriculture,Trakia University, 6000 Stara Zagora, Bulgaria 2Agricultural Institute, 3 Simeon Veliki, 9700 Shumen, Bulgaria

(Manuscript received 10 September 2017; accepted for publication 17 November 2017)

Abstract. The aim of the study was to establish the levels of the main selection traits which determine the technological wool production in the rams from the breed of Caucasian merino sheep. The study included a total of 126 rams at 18 months of age from Caucasian merino breed. To determine the fibre diameter, a total of 252 wool samples from two parts of the body (sideandleg) were analyzed.For laboratory examination of staple lengt handcrimp of wool, a total 36 wool samples (from the side and the leg) were studied. The rams from Caucasian breed had a very good topographic equality of fiber thickness and staple length. The average fiber diameter of the side was 21.98μm (with variation from 21.71μm to 22.30 μm) and the leg was 23.05μm (with variation from 22.76μm to 23.34μm).The wool`s fineness in the fleecewas 64’s quality in 76.98% of the samples, which characterized it as a fine merinowool.The number of crimps per 1 cm in the rams was an average of 5.07 nrs. on the side and 4.46 nrs. on the leg and in the rams at 18 months of age – 5.26 nrs. and 4.82 nrs., respectively.

Effect of the herbicide treatment dose on the weed infestation in common winter wheat

Z. Petrova*

Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria
(Manuscript received 10 June 2017; accepted for publication 24 October 2017)

Abstract. The aim of this investigation was to determine the effect of the treatment dose of herbicides on the weed infestation in common winter wheat. The investigations were carried out during 2015 –2016 at Dobrudzha Agricultural Institute (DAI) – General Toshevo. The following herbicides were used: Derby super WG (33 g/ha; 66 g/ha; 132 g/ha), Secator ОD (100 ml/ha; 200 ml/ha; 400 ml/ha), Ergon WG (50 g/ha; 100 g/ha; 200 g/ha), Granstar super 50SG (40 g/ha; 80 g/ha; 160 g/ha), Lintur 70WG (150 g/ha; 300 g/ha; 600 g/ha) and Mustang 306.25 СК (800 ml/ha; 1600 ml/ha; 3200 ml/ha) from the group of sulfunylureas with various mechanism of action. The preparations were applied at three doses – optimal, double and quadruple, at stage 29 (according to Zadoks et al., 1974) of common winter wheat cultivars Dragana, Zlatitsa and Kalina. The herbicide effect was determined by the quantitative weight method and evaluated by the EWRS scale. Regardless of the used dose and the cultivar, Derby super WG, Secator OD, Lintur 70WG and Mustang 306.25СК had highest efficiency (100%) against the following investigated weeds: Sinapis arvensis L., Matricaria chamomilla L., Anthemis arvensis L., Galium tricorne (Stock.), Consolida orientalis (J. Gay) and Cirsium arvensis L. Ergon WG and Granstar super 50SG had 100% efficiency against Sinapis arvensis L., Matricaria chamomilla L. and Anthemis arvensis L. and lower effect (90-94%) on Galium tricorne (Stock), Consolida orientalis (J. Gay) and Cirsium arvensis L.

Productivity of durum wheat cultivar Predel at nitrogen-phosphorous fertilization

L. Plescuta*

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 30 June 2017; accepted for publication 10 October 2017)

Abstract. The effect of nitrogen-phosphorus fertilization at nitrogen rates 0, 80, 120 and 160 kg.ha-1 and 0, 80 and 120 kg.ha-1 for phosphorus has been studied in durum wheat Predel cultivar, grown on leached vertisol soil type during the period 2012-2014 in the field of the Field Crops Institute – Chirpan. The results show that at alone nitrogen fertilization grain yield reaches 3,75 t.ha-1 at moderate N120, while at alone phosphorus fertilization the increase compared to the non- fertilized control (2,50 t.ha-1) is insignificant. At combined N120P120 the highest grain yield was obtained during the period – 4.50 t.ha-1, with 57.41% above the control. The harvest index of durum wheat grain variety Predel is 0.353 on average. Good HI results are formed at fertilization with P120 and N80P80.


Length of the growing season and yield in Triticum monococcum L., in accordance with the growing conditions

S. Stamatov*, E. Valchinova, G. Desheva, K. Uzundzhalieva, P. Chavdarov, T. Cholakov, B. Kyosev, R. Ruseva, N. Velcheva

Institute of Plant genetic resources „Konstantin Malkov”, 4122 Sadovo, Bulgaria (Manuscript received 7 June 2017; accepted for publication 1 September 2017)

Abstract. The aim of the current study is to trace the changes in the length of the growing season in accordance with the accumulated effective temperatures, rains and plant nutrition during the vegetation period, as well as the influence of these indices on the grain yield. The study was conducted in the period 2015 – 2016 in the experimental field of Institute of Plant Genetic Resources – Sadovo with the local variety B3E0025 from the National Genebank in Sadovo. The experiment was made in block method in four repetitions. Three sowing times were made – autumn, winter and early spring and two options of N fertilization – without additional N and 3 kg/da input of active N substance in tillеring phase. The beginning of the basic phenophases has been observed. As a result of the study it was established that the vegetation period in T. monococcum L. has 114-238 days’ duration and accumulation of effective temperature of 2266.0- 2714.71°C. The length of the growing season and the necessary accumulated temperature depends on the sowing period, the predecessor, the amount of nutrient substances and soil moisture. The extension of the critical phases of autumn sowing favours the obtaining of higher yield. The significance of the effective temperatures decreases with additional N input.

Study on the emptying time of grain harvester hoppers

K. Trendafilov1, N. Delchev2, B. Kolev3, G. Tihanov21Department of Mechanical Engineering, Faculty of Technics and Technologies – Yambol, Trakia University,
6000 Stara Zagora, Bulgaria
2Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
3Department of Agricultural Machinery, Agrarian and Industrial Faculty, “Angel Kanchev” University of Ruse, 7017 Ruse, Bulgaria
(Manuscript received 4 January 2017; accepted for publication 11 April 2017)

Abstract. When unloading grain harvester hoppers at a standstill the emptying time has an effect on the grain harvester performance. A study has been conducted on the actual emptying time of harvester grain hoppers on various farms in Bulgaria and the actual flow rate of the unloading auger has been determined. The results obtained have been compared to the designed ones. It has been established that when unloading at a standstill the full rate of the unloading auger is not in use, but only 73.14% of it, with which the hopper emptying time is 1.4 times greater than the theoretical one.

Lucrative status of improved dual purpose cowpea (Vigna unguiculata L., Walp) in Damboa, Borno State, North-Eastern Nigeria

B.H. Gabdo*

Department of Agricultural Economics and Extension, Adamawa State University, Mubi, Adamawa State, Nigeria (Manuscript received 22 May 2017; accepted for publication 27 October 2017)

Abstract.Thisstudydivulgedthecost-returnsanalysisbetweenimproveddualpurposecowpea (IDPC)varietiesandothernon-IDPC/localcowpeavarieties in Azir, Damboa town, Kuboa and Sabongari villages of Damboa local council, Borno State, Nigeria. Socio-economic stratification of the villages into Low Population Low Market (LPLM) and Low Population High Market (LPHM) on the basis of human demographic profile and proximity to wholesale market were the criteria adopted for selecting the villages for this study. A total of 150 cowpea farmers responded to the questionnaire instrument; administered between December, 2006 and February, 2007. Results of the budgetary techniques used show that adopters of IDPC varieties generate $386.01ha-1 as net income as against $248.37ha-1 for the non-IDPC adopters; proportional to 55.42% rise in net income per hectare of cowpea resulting from the impact factor of IDPC adoption alone. Similarly, farmers in Sabongari village realized the highest net income of $491.99ha-1 as against Azir the lowest net income of $247.21ha-1 across the four villages owing to demand factor; interplay between human population and proximity to wholesale market; both in favour of Sabongari but none in favour of Azir. In terms of ratios, farmers in Sabongari were adjudged as more lucrative across adopters’ category, socio-economic domain and villages respectively owing to higher return on sale ratio and lower operating ratio. Azir and Sabongari villages were found to exhibit potentiality for comparative cost advantage and comparative sales advantage respectively. Thus, the research concludes that an expansion path for cowpea is feasible if cultivation and sales are premised on cost and sales advantages.

Present status of Zymoseptoria tritici (Mycospharella graminicola /Fuckel/ Schroter) of the wheat cultures in the Republic of Macedonia

I. Karov*, E. Arsov

Department of Plant and Environmental Protection, Faculty of Agriculture, Goce Delcev University, Krste Misirkov, 2000 Stip, Republic of Macedonia (Manuscript received 6 July 2017; accepted for publication 31 August 2017)

Abstract. In the Republic of Macedonia, wheat is a very important crop and it is grown on an area of around 250.000 ha. The most important regions for wheat growing are: Bitola, Kumanovo, Sveti Nikole, Skopje, Probistip, Kocani, Veles and Stip. The most important deseases on wheat are: Tapesia yallundae Wallwork and Spooner with its anamorphic stage Pseudocercosporella herpotrichoides (Fron) Deighton causer of the desease „eyespot“ on barley and wheat; Puccinia graminis f. spp. tritici; Puccinia racondita f. spp. tritici; Gaeumannomyces graminis var. tritici; Bipolaris sorokiniana (Sacc.) Shoemaker; Blumeria graminis var. tritici and Zymoseptoria tritici (Mycospharella graminicola (Fuckel) Schroter). Many new diseases on wheat causing significant economic damage to producers are observed in Macedonia. The main aim of this article is to present the symptoms, morphology and protective measures of Zymoseptoria tritici (Mycospharella graminicola), the most widely spread fungal pathogens on wheat in the Republic of Macedonia. In the period between 2014 and 2016, the pathogen fungi on wheat with the highest intensity were: Zymoseptoria tritici, Tapesia yallundae, Puccinia graminis, Puccinia recondita, Gaeumannomyces graminis, Bipolaris sorokiniana, Blumeria graminis. The intensity of the diseases and the damages – yield losses of wheat, differed from year to year and between regions, depended on the sensitivity of the wheat varieties. The smallest yield loss was identified in wheat producers who treated the wheat with pesticides at least twice for vegetation season.