Heritability of osmoregulation ability at durum wheat

V. Bozhanova, D. Dechev

The osmoregulation is one of the most important cell adaptation mechanisms occurred at beginning of drought. The inheritance of osmoregulation ability in durum wheat by using indirect method for trait measuring was studied. Five durum wheat genotypes with different level of tolerance to osmotic stress were included in diallel crossing scheme. Among the parents genotypes the old Bulgarian cultivar A-223 distinguishes with the lowest seedlings growth depression coeficient of 32,5 %, i.e. with best ability of osmotic regulation. The lowest osmotic regulation ability shows cultivar Gergana. The hybrid combinations including the most tolerant parent A-223 show the lowest coeficient of depression among the F hybrids. The conducted dialel analyses shows 1 the high significance of the effects of the general (GCA) and specific combinative ability (SCA) during the all 3 years of the investigation. The inheritance of high levels of osmoregulation is determinted by both the aditive and non-aditive gene effects. The non-aditive gene efects (SCA) strongly predominate over the aditive and have a significant role in the observed big heterozis effect. The significance of variances of both GCA and SCA requires the selection of single plants by investigated traits to be shifted in the later segregating progenies.

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Theoretical study of absorption refrigeration system thermally activated by a vacuum pipe solar collector

A theoretical study has been carried out of a conceptual absorption refrigeration system for air conditioning that is energy activated by a solar collector field. The dynamics of the heat ratio describing the efficiency of the unit at various coolant temperatures to the generator has been studied at various temperature condensation conditions. Mean temperature ranges are determined for the effective operation of the generator. Definitely temperature level of condensation of refrigeration unit, which over the effectiveness of the refrigeration unit sharply reduced. The proposed model is cooling purposes in pig and poultry farming.

Theoretical study of absorption refrigeration system thermally activated by a vacuum pipe solar collector

K. Peychev, R. Georgiev, D. Dimitrova

Determination of minimum heat insulation thickness for an experimental methane bioreactor

The objective of this paper is to establish the minimum thickness of heat insulation for an experimental bioreactor, developed at the Institute of Microbiology of the Bulgarian Academy of Sciences, required to ensure heating of the fermentor with its own produced biogas. The experimental bioreactor is a cylinder of height h=935 mm and diameter d=435 mm. It has a water jacket around its shell to heat up the substrate. It is made in stainless steel of thickness 5 mm and of heat transfer coefficient =45 W/m.К. The fermentor is intended to be filled with substrate at 75-80 % of its volume. The bioreactor is designed with heat insulation in mineral wool of heat transfer coefficient =0.035 W/m.К. The biogas output of the bioreactor is 78 dm3 per 24 hours at energy value 6 kWh/m3. Heat loss of the fermentor is calculated using classical heat engineering equations. It is assumed that the substrate heated up in the bioreactor is a high inertia heat system which because of its large mass and not high temperature, will be exposed not to the impacts of the average day and night temperature, but to the monthly average. Results were obtained for the heat transfer coefficient and heat loss of the bioreactor (filled with cattle dung diluted in water) in mesophilic (35 oC) and thermophilic (55 C) mode at different insulation thicknesses. Heat loss of the bioreactor in thermophilic operation mode is 57% higher than in mesophilic mode. The main conclusion from the research is that small bioreactors cannot ensure heating at their own using the produced biogas in wintertime. A highly efficient heat insulation of thickness of about 10 cm is advisable.

Determination of minimum heat insulation thickness for an experimental methane bioreactor

R. Georgiev, K. Peychev, I. Simeonov, A. Alexandrov

Variation in lipid abundance and composition in a fire affected hillside from Lyulin mountain, Bulgaria

Top soils from a fire-affected catena sequence on the Southern hillside of Lyulin Mountain, Bulgaria were analysed for free lipids with the aim to identify molecular markers of the effect of fire on soil organic matter. The total lipid extract of the unburned control soil was dominated by aliphatic series of  alkanes, alkanoic acids, alkanols, diterpenoids and steroids indicating the predominant higher plant input. The alkane patterns as revealed by the carbon preference index (CPI) and the average chain length (ACL) showed higher relative abundance of short chain homologues (C – C ) in the burned soils as 13 20 compared to the control soil and indicated a thermal, but also a microbial input. The fatty acids and alkanols signatures, as well as the typical biomarker signals for pine such as pimaric acid and methyldehydroabietate were lost in the chromatogram of the severely burnt soil on the ridge of the mountain. All samples displayed a particular pattern of short- and long-chain and even carbon numbered n-alkanes (maximum at C and C ). Aromatic hydrocarbons and 29 27 oxygenated acids were more abundant in the burnt soil on the ridge while the pine signals of pimaric acid and dehydroabietic acid disappeared.

Variation in lipid abundance and composition in a fire affected hillside from Lyulin mountain, Bulgaria

I. Atanassova, M. Teoharov

Animal hygiene and ecological assessment of air pollution in a pig-farm for 50 sows

The aim of this study was to determine air pollution with ammonia, hydrogen sulfide, total dust, microorganisms (saprophytic and coliform bacteria, including Escherichia coli) from a pig farm for 50 sows (average daily capacity 532 pigs from different categories). The pollutants were investigated in five points as follows: emissions from production buildings – Point 1 (P ) – building for farrowing sows and Point 2 (P ) – building for fattening pigs; imissions in ambient air- 1 2 Point 3 (P ) – at 2 m, and Point 4 (P ) – at 50 m distance from the buildings under the wind side position, and Point 5 (P ) – at 10 m distance – over the wind side 3 4 5 position of the farm. The levels of the hydrogen sulfide (3.31-7.10 mg.m-3), total dust (0.71-5.11 mg.m-3) and number of cultivable microorganisms (13,0 x 103 – 428,0 x 103/m-3) in the air of the buildings (P and P ) were within the animal hygiene requirements, except the ammonia (3.32-15.82 mg.m-3) which 1 2 concentrations exceeded the norm. The air quality for the staff as a factor of working environment in the buildings covered all requirements. Emissions of NH , 3 H S, total dust and microorganisms from the farm buildings maintain measurable concentrations of these pollutants (imission) at 50 m leeward and at 10 m over 2 wind side of the farm. With increasing the distance from the production buildings contents of NH , H S, dust and microorganisms in the air decreased from 1.4 to 3 2 13.7 times at P and from 1.4 to 16.7 times at P . The air quality around the pig farm did not correspond with the norms at P , and at P , regarding the content of 4 5 4 5 ammonia and total dust. For the content of hydrogen sulfide that finding applies to P and P . Statistical differences (P Ў 0.05 – 0.001) were established at the 3 5 levels of the investigated pollutants of the air between seasons (summer, autumn, winter) in the same point and between different points at the same season.

Animal hygiene and ecological assessment of air pollution in a pig-farm for 50 sows

G. Petkov, G. Kostadinova, R. Stefanova, T. Penev, P. Gercheva

Effect of fertilization and predecessor on chemical composition and energy value of wintering oats grain

A study has been conducted at the Experimental Station of Agriculture, Sredets to establish the effect of predecessor and mineral fertilization on chemical composition and energy value of wintering oats grain. The object of this study was wintering oat (Avena sativa L) variety Jubile cultivated after predecessors (A): stubble (A ), sorghum (Sorghum vulgare Pers) -(A ) and rape (Brassica napus var. oleifera L) -(A ) and fertilization, kg/ha – (B): N P K -B ; 1 2 3 40 100 50 1 N P K -B ; N P K -B and B control N P K .The study covers chemical analysis of wintering oats grain made by Weende method. Calculations for the 80 100 50 2 120 100 50 3 0 – 0 100 50. nutritive value of feed grain based on data obtained from chemical analysis were made (for ruminants) expressed in gross energy (GE) – MJ/kg dry substance, metabolizable energy (ME) – MJ/kg dry substance, feed units for milk ( FUM, kg) and feed units for growth (FUG, kg) of dry substance – by using empirical equations. It was found that the predecessors stubble and rape increase the content of crude protein, crude fat and crude fibers in oats by 10.5 and 12.1%, 5.2 and 3.9%, 5.6 and 1.2%. The content of minerals and nitrogen-free extract (NFE ) was the highest after predecessor sorghum. Increasing the doses of nitrogen fertilizer led to increasing the content of crude protein and fibers in grains on average by 14.4% and decreases the content of crude fats, ash and NFE by 7.0%, 3.2% and 3.4%, respectively. The differences in chemical composition of oat grains did not have a significant impact on its energy value expressed by GE, ME,
(FUM) and (FUG).

Effect of fertilization and predecessor on chemical composition and energy value of wintering oats grain

M. Dimitrova – Doneva, R. Petkova

Economic evaluation of winter wheat leaf fertilization

During the years 2006-2009 field experiment with winter wheat was held in the region of Stara Zagora. The object of study is the economic impact of leaf treatment with liquid fertilizer micro on productivity of winter wheat. Field experiment includes the following study options: control; fertilization with Wuxal Mikroplant; Wuxal Mikroplant and Kodiche applied in combination, Fertilider; Wuxal Copper. Foliar treatment with micro-fertilizer was made after booting, before inflorescence emergence, during intensive growth and development of plants, where the need for nutrients is the greatest. Economic analysis of the results show that the application of liquid fertilizers leads to low production cost. The cost of grain decreased to 40% of the control average for the period of study. It is therefore recommended for winter wheat, before inflorescence emergence to make leaf fertilization. Research shows that the introduction of microfertilizers 9 to 36 percent increase profitability compared to conventionally grown winter wheat.

Economic evaluation of winter wheat leaf fertilization

A. Stoyanova, I. Gospodinov, R. Petkova

Designing lavender plantations in relation to the mechanized harvesting of lavender blossom

For the efficient use of lavender harvesting aggregates and transportation vehicles it is necessary as early as with the designing of the lavender plantation to take into account their parameters. Two approaches have been considered in designing new lavender plantations: use of minimum number of transportation vehicles in the field and forming a minimum number of intermediary roads for unloading. The first approach means small length of sections which the field is divided into in order to fill the machine hopper in two goes. That allows unloading of the hopper on one end of the section only and needs one transportation vehicle. With the second approach sections are of greater length. Unloading is done at both ends of the section and two waiting transportation vehicles are needed, but the number of intermediary roads is smaller and agricultural land is used more efficiently. Correlations have been found for defining the number and length of sections which the field has to be divided into when establishing the lavender plantation. A method has been identified for defining the kinematic length and width of various lavender harvesting aggregates – symmetric and non-symmetric, correlations for defining the length of various turns performed by aggregates, as well as the width of stripes for the turning of aggregates at the end of sections on the field.

Designing lavender plantations in relation to the mechanized harvesting of lavender blossom

K. Trendafilov, N. Delchev

Effect of dietary exogenous phytase supplementation in growing and fattening pigs

Three balance feeding trials were performed with 3 groups male castrated pigs during the starter, grower and finisher periods. The animals were housed in specially designs individual cages that allowed for separate collection of urine and faeces. Each trial comprised 5 days preliminary and 5 days experimental period. Pigs were fed compound feeds according to their genotype and age. The first groups received compound feed without exogenous phytase. The feed of the second group was supplemented with the Bulgarian enzyme preparations Optiphos at 0.01 %, аnd the feed of group III – with the same amount of the enzyme preparation Natuphos. The results showed that the inclusion of exogenous phytase in compound feeds for pigs permitted to decrease the amounts of used dicalcium phosphtate by 3 to 7 times. This reduced the amount of total dietary phosphorus by 27-30 % and the cost of feeds. The utilization of phytase improved the absorption of phosphorus by 28-34 % and decreased its total output by 38-45 %, without any effect upon nitrogen retention. The performed trials did not shown any significant difference between the effects of both exogenous phytases used: Optiphos and Natuphos.

Effect of dietary exogenous phytase supplementation in growing and fattening pigs

А. Ilchev

Evaluation of the stability and adaptability of the Bulgarian lavender sorts yield

In the years 2005-2009 six Bulgarian sorts of lavender were tested for fresh blossom yield and essential oil yield, as well as one seed population, formed by the seed offspring of these sorts. With all studied sorts and seed population, the fresh raceme yield and the essential oil yield are mostly affected by the specific interaction between the genotype and the current year conditions of cultivation – 69% and 80.4%. The “Druzhba”, “Sevtopolis”, “Yubileina” and “Hebar” sorts are characterised with a high adaptability, but they retain their yield stability only when the soil and climate conditions of cultivation are good. The “Hemus”, and “Raya” sorts and their seed population give highly stable yields even in less favourable conditions of cultivation.

Еvaluation of the stability and adaptability of the Bulgarian lavender sorts yield

S. Stanev