Productive capacity of the maize for silage crop grown in disturbed irrigation regime

An experiment was conducted with maize for silage as a main irrigation culture in the experimental field of the Agricultural Institute - Stara Zagora. The following variations have been tested: variation 1 - no irrigation (sentinel); variation 2 - optimal irrigation, 80%-85% of FC (100% irrigation); variation 3 - Irrigation as variation 2 but with first irrigation cancelled; variation 4 - irrigation as variation 2 but with second irrigation cancelled; variation 5 - irrigation as variation 2, but with third irrigation cancelled. On the basis of a chemical analysis of the sudangrass forage for the raw protein content, FUM, FUG and PDI were defined. It was found that the highest yield of raw maize protein grown as the main crop was obtained from the optimal irrigation variation, both in the non-fertilized and the fertilized variation, respectively with 1023.5 kg / ha and 1303.5 kg / ha. The optimal water supply of maize provides the highest energy efficiency of the forage expressed in FUM -15022.8 kg / ha, FUG -15584.4 kg / da, PDI - 1060 kg / ha for non fertilized variations and FUM -16873.5 kg / ha, FUG -17516.3 kg / ha, PDI-1219 kg / ha with fertilizer applied.

Regularities in the formation of entomofauna in alfalfa agrocenosis

The field work was performed at the experimental field of the Institute of Forage Crops, Pleven, Bulgaria during the period of 2006-2009. The share distribution of the orders Coleoptera, Thysanoptera, Diptera, Orthoptera and Hemiptera, suborder Sternorrhyncha, Heteroptera, Fulgoromorpha and Cicadomorpha was established for every four alfalfa growth cycles during the vegetation period for four years. It was found that the share participation of orders was determined primarily by the population dynamics of the dominant insect species and it was closely dependent on plant development following a characteristic course over the years. Depending on the food specialization and the division of the species into harmful and beneficial, the share of predators in regrowth corresponded to that of their prey. A clear trend was observed of increasing the share of harmful species and reducing the beneficial ones (Coleoptera, Thysanoptera, Hemiptera: Heteroptera) with the alfalfa development over the years.

Productivity and chemical composition of green biomass from Sudan grass, grown as a second crop, with optimal and insufficient water supply

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).

Essential oil content and composition of lavender origins, introduced in Bulgaria

The genus Lavandula includes a variety of species under the common name lavender. Bulgaria has a tradition in the production of high-quality lavender oil. This is the result of many years of selection work, which includes the study of introduced samples and their adaptogenic abilities in the country habitat. Three samples of Lavandula angustifolia Mill., that originated from Poland were studied and compared with the Bulgarian varieties “Hemus” and “Sevtopolis”. The content of the essential oils ranged from 0.39% to 3.98%. The chemical composition, determined by GC/MS, revealed the main compounds: linalyl acetate (13.0÷44.9 %), linalool (21.8÷42.1%), β-caryophyllene (4.6÷7.4 %), cis-β ocimene (2.8÷10.5 %), lavandulyl acetate (1.9÷4.3%), terpinen-4-ol (0.3÷2.0 %), limonene+1.8 cineole (2.3÷6.0 %) and trans-β ocimene (0.1÷3.8%). The sample with the dark purple florescence showed promising quantitative and qualitative characteristics of the essential oil and can be involved in the selection program for lavender cultivation.

The ameliorative effect of protein hydrolysate on the imazamox-damaged young wheat plants

The plant biostimulants (PBs) are a wide range of microbial and/or organic compounds applied to crops to improve the physiological processes such as nutrition efficiency, plant development and abiotic stress tolerance. Imazamox is a herbicide characterised with a wide spectrum of weed control, low application rates and low mammalian toxicity, but also with a high soil persistence. Therefore, the residual amounts of imazamox may negatively affect subsequent sensitive crops in the crop rotation. In the current study we investigated the effect of a single and combined treatment with imazamox and a plant biostimulant (protein hydrolisate) on the antioxidative defense system and the detoxification metabolism of wheat young plants. The result showed that the seed imbibition with 10 μM imazamox inhibits the growth of the young wheat plants. A slight improvement was found due to the additional treatment with protein hydrolysate of the wheat plants damaged by imazamox herbicide. According to the results, this improving effect on the growth does not ameliorate the plant detoxification metabolism such as glutathione S-transferases or antioxidative defense. However, the improving effect is low and insufficient to restore the plant growth and functioning and its effects on wheat production are not studied yet.

Features of the temperature regime effect on the duration of the crops vegetation period in Southern Ukraine

When modeling the prognostic changes in the temperature regime over the territory of Ukraine, the data of the research project for modeling the regional climate and assessing the consequences of its change (CORDEX) were used. The climate projection structure is based on a series of global climatic models (GCM) developed within the framework of CMIP5 project. The influence of the temperature factors on passing the phenological phases and oats yield in the South of Ukraine, implementing the RCP4.5 and RCP8.5 climate scenarios and comparing them with the long-term data is analyzed. As a result of the analysis of the changes in the temperature regime it was revealed that it will be warming the plants vegetation period. The probable change in the oats yield in the southern part of Ukraine under the conditions of climate change using the crop formation model was considered. It is assumed that by 2050 the timing of sowing and germinating the seedlings will be shifted to an earlier date, and the oats yield will increase by 1.26-1.32 times.

Helminths and helminth communities of Carassius gibelio (Bloch, 1782) from the Panicheri Reservoir, Aegean Water Basin, Bulgaria

Ecologoparasitological research was done based on the helminths and helminth communities of the Prussian carp (Carassius gibelio (Bloch, 1782)) from the freshwater ecosystem of the Panicheri Reservoir, Aegean Water Basin, Bulgaria. As a result of the examined nine specimens of the Prussian carp, two species of helminths were found: Ligula intestinalis (Linnaeus, 1758), larvae and Pomphorhynchus laevis (Müller, 1776). The dominant structure of the helminth communities was determined. The Panicheri Reservoir is a new habitat in Bulgaria of P. laevis and L. intestinalis from C. gibelio. C. gibelio is a new host record for L. intestinalis in Bulgaria. The two helminth species are core species for the helminth communities of the examined species of the freshwater fish. P. laevis was distinguished with higher prevalence and mean intensity (P%=33.34; MI=1.34) than L. intestinalis (P%=22.23; MI=1.0). The circulatory pathways of the helminth flow were traced.

The impact of soil herbicides on the yield and quality of lavender (Lavandula angustifolia Mill.) essential oil

During the period 2014 – 2015 the herbicidal effect and the selectivity of isoxaflutole (Merlin 750 WG), oxadiargyl (Raft 400 SC), imazamox (Pulsar 40) and flumioxazine (Pledge 50 VP) were studied on lavender fields, Hemus and Jubilejna varieties. The present work focuses on the influence of low doses of the applied preparations on the yield and composition of the essential oil compared with untreated control. The results of two-year studies show that the treated variants have a higher yield on average of 0.7-1.6 kg / dka. The odoriferous ingredients range in the limits: linalyl acetate (20.0 - 38.6 %); linalool (20.6 - 46.2 %); lavandulyl acetate (1.9 - 5.9 %); 1,8 cineole (0,4 - 4,9 %) and camphor (0,2 - 0,6 %). Applying oxidiarigil results in greater changes in the composition of the Jubilejna variety, whereas the Hemus variety has the most influence by isoxaflutole.

Weed infestation monitoring in vineyards in the South Sakar region of Bulgaria

The weed infestation monitoring was conducted in 2019 and 2020. The purpose was to document the weed flora in a large part of the wine vineyard plots in the cadastral area of the Kolarovo, Ovcharovo, Dositeevo, Balgarin and Izvorovo villages within the administrative territory of the Harmanli municipality and the micro-climatic region of South Sakar. The established weed species composition was represented by 38 weed species belonging to 18 botanical families in ratio 81.58% to 18.42% monocarpous to polycarpous species classified in a total of nine biological groups.

The effect of the substitution of grain components with a high proportion of bakery wastes on the Clarc of energy distribution and the Clarc of protein transformation in the eco-technical chain ‘fodder – layer’s eggs’

The including of 15 and 20% bread wastes in the combined fodders for layers of net utilization of energy and protein has been studied. Two new indexes of net utilization have been introduced: Clarc of energy distribution (CED) – the relation between consumed metabolizable energy and accumulated gross energy in the egg mélange and Clarc of protein transformation - the relation between consumed crude protein and accumulated crude protein in the egg mélange. The following results have been established: CED (fodder – egg mélange): Control group – 0.1820; 15% bread wastes – 0.1851; 20% bread wastes – 0.1887; CPT(fodder – egg mélange) - 0.2358; 0.2405 and 0.2460 respectively. The authors establish a tendency for hens that have consumed more bread wastes to show a higher effectiveness for the net protein transformation.