Estimation of the economic efficiency of Lacaune sheep farms, based on theoretical bio-economic models

S. Slavova*

Agricultural Institute, 6000 Stara Zagora, Bulgaria

(Manuscript received 24 November 2020; accepted for publication 26 April 2021)

Abstract. The aim of the present study was to develop theoretical bio-economic models of Lacaune sheep farms and establish their economic efficiency. Based on three main criteria, 15 options were considered and analyzed. Data were processed using the program EWSH2 as a part of ECOWEIGHT Package for calculating economic weights in livestock. Revenues from sales, variable costs, gross margin and profitability before and after subsidies and per ewe were calculated. It was found that raising sheep of the high productive Lacaune breed could generate profit and provide profitability for the studied models of farms, regardless of the level of selection, type of production system, flock size and even the amount of subsidies. Nucleus farms reported the largest gross margin, followed by the basic and commercial farms. Profitability without subsidies showed the highest values for the nucleus flocks of 1000 ewes – 24.24% when adopting semi-intensive production system and 23.14% for the intensive one. With the addition of subsidies, nucleus and basic farms of 1000 ewes were considered the most profitable with 40% and 37.37%, as for both options the semi-intensive conditions were preferable. A tendency for the values of the studied indicators to grow with the increase in the number of ewes in the flocks was observed, as only for the variable costs it was reversed. Due to the lack of studies on economic efficiency of Lacaune sheep farms in Bulgaria, an additional detailed research, based on real data, is advisable to be conducted.

 

Effect of irrigation rate on Sudan grass yield, grown as a second crop

R. Bazitov*

Agricultural Institute, 6000 Stara Zagora, Bulgaria

(Manuscript received 24 October 2020; accepted for publication 12 May 2021)

Abstract. The aim of the present study was to establish the effect of irrigation rate on the yield of Sudan grass variety Engje-1, grown as a second crop for silage on meadow-cinnamon soil for the region of Southern Bulgaria. For this purpose, an experiment with Sudan grass variety Endje-1 on the experimental field of the Agricultural Institute – Stara Zagora, after its predecessor barley, was conducted. The Sudan grass was harvested in the brooming stage. Five variants were explored: Variant 1 – without irrigation (control); Variant 2 – with optimal irrigation, 75-80% of field capacity (FC); Variant 3 – irrigation as Var.2 but with removal of the first watering; Variant 4 – irrigation as Var.2 but with removal of the second watering; Variant 5 – irrigation as Var.2, but with removal of the third watering. It was found that the efficiency of 1m3 of irrigation water was the highest at the optimum variant (Var.2), where 5.36 kg of dry mass (DM) were produced by 1 m3 of water. With the removal of the second irrigation (Var.4), the yield on the dry mass decreased by 6.4% compared to the optimal variant (Var.2), and with the removal of the first irrigation (Var.3) the losses on the dry mass reached, 12.3%, respectively. The highest values of this indicator were obtained by varying the second irigation (Vаr.4) – 7.53 kgDM/m3 water. The coefficient of efficiency of the irrigation rate, representing the ratio between the increase of the yield (in comparison with the version without irrigation – Vаr.1), and the size of the realized irrigation norm had the highest value in the version without second irrigation (Vаr.4) and the lowest values for the version without first irrigation (Vаr.3).

Simulated acid rain impact on growth, yield and leaf anatomy of Dioscorea rotundata (L.)

E.P. Edosa*, J.F. Bamidele

Department of Plant Biology and Biotechnology, Faculty of Life Science, University of Benin, P.M.B. 1154, Benin City, Edo State, Nigeria

(Manuscript received 23 September 2020; accepted for publication 26 March 2021)

Abstract. Acid rain causes damage to crops and also has adverse effect on the soil and the environment. These have led to the abandonment of farmlands in affected areas. Southern Nigeria which is known for yam cultivation is subjected to acid rain resulting from gas flaring activities, importation of fairly used vehicles, power generation and industrial activities. The growth, yield and leaf anatomy response of Dioscorea rotundata (L.) exposed to simulated acid rain (SAR) of pH 2.0, 3.0, 4.0 and 6.0 (control) was investigated. Acid rain exposure caused morphological changes in plants including chlorosis, necrosis, and leaf folding. Acidic precipitation inhibited vine length, leaf number, chlorophyll content index and leaf area at pH 2.0; while growth was encouraged at pH 6.0. 22% of leaf surface area of D. rotundata L, was injured after simulated acid rain treatment at pH 2.0 while necrosis was absent at the (control) pH 6.0. Harvest index of D. rotundata was not significantly different (p>0.05) between the pH treatment groups; however, was slightly higher at the (control) pH 6.0. Percentage dry matter partitioning of D. rotundata leaf and stem was not affected by the acid rain exposure; nevertheless, maximum percentage dry matter of tuber was obtained at pH 4.0 and pH 6.0. Transverse sections of D. rotundata leaves showed cuticle wax damage and rupture of epidermis at lower pH 2.0 and 3.0. Mesophyll degradation and cytoplasm depletion was also observed in the treated leaves. The plant leaves revealed dark tissues in necrotic areas which may be phenolic compounds secretion. However, it became clear that significant increases in the growth parameters considered occurred at pH 6.0 (control).

Assessment of morphological variations in wild populations of Nile tilapia from South West Nigeria

O.M. Popoola*, A. Ebiwonjumi

Department of Fisheries and Aquaculture, Federal University of Technology, Akure, Nigeria

(Manuscript received 31 October 2020; accepted for publication 20 February 2021)

Abstract. The pattern of morphological variations among Oreochromis niloticus (Linnaeus, 1758) (Cichlidae; Teleostei) from three populations from South West Nigeria (Asejire reservoir, Ureje reservoir and Ogbese River were examined (n=10 speciments from each water body) with a view to investigate the genetic diversity using morphometrics and meristics indices. In general, 77.22% of the total variation in the sampled populations is from first principal component (PC1) and the characters that contributed to this variation are with pre-dorsal length, pre-pectoral length, pre-anal length, dorsal spine length and anal spine length. Canonical variate analysis (CVA) showed that O. niloticus populations from the three water bodies formed a separate cluster from each other and that there was an intersection between the Asejire and Ureje reservoirs samples and the Asejire reservoir with Ogbese River samples. However, the samples from Ureje reservoir and Ogbese River had no intersection. Cluster analysis revealed two major clusters with Ureje reservoir samples belong to one and Ogbese River and Asejire reservoir fall in the other cluster. Principal Components for meristic (PC1 and PC2) accounted for 46.49% and 24.17% revealed that transverse scales and scales surrounding the caudal peduncle, pre-dorsal scales accounted for the variation. The CVA revealed that of all the populations sampled, samples from Ureje reservoir are more diverse that the other two populations. The research disclosed that there is variation in O. niloticus populations from the three water bodies, which could be a result of genetic structure and environmental conditions, being major factors affecting morphological variability among different geographical populations. Further study on genetic differentiation of individuals from different species is necessary to confirm findings of the present study.

Physiological responses of Vicia faba to copper toxicity

S. Benouis1,2*, H.A. Reguieg Yssaad1, E.H. Bouziani1, I. Khedim1

1Laboratory of Biodiversity and Conservation of Water and Soils, Faculty of Nature and Life Sciences, University of Abdelhamid Ibn Badis, Mostaganem, Algeria
2Scientific and Technical Research Center on Arid Regions (CRSTRA) Biskra, Algeria

(Manuscript received 21 July 2020; accepted for publication 26 February 2021)

*e-mail: simoslimane1985@gmail.com; slimane_benouis@yahoo.fr

Abstract. Copper plays an important role in multiple plant physiological processes including photosynthesis and protein synthesis. Excess copper in tissues leads to physiological and biochemical disturbances. In order to determine the physiological response of Vicia faba L. to copper toxicity, two varieties (Sidi Aïch and Super Aguadulce) were grown in a substrate of sand and compost (3V/V) and contaminated by different doses of Cu (0, 80, 160, 240, 320, 400 mg kg-1). Dose rates ≥160 mg kg-1 led to the accumulation of copper in roots and shoots, in turn leading to decreases in photosynthetic activity and protein content and to the accumulation of proline, a stress indicator, and soluble sugars.

Productivity and feed quality of Sudan grass (Sorghum sudanense (Piper) Stapf.) and sweet sorghum forms

S. Enchev*

Agricultural Institute, 3 Simeon Veliki, 9700 Shumen, Bulgaria

(Manuscript received 24 August 2020; accepted for publication 22 February 2021)

Abstract. During the period 2017-2018, the feed quality and productivity of three Sudan grass varieties – Endje 1, Vercors and Super Sweet, one stabilized Sudan grass population – SWT, local sweet sorghum – „Zaharna metla“ population and the sweet sorghum cultivar “Shumensko sladko” were researched in Agricultural Institute – Shumen. Green mass (t/ha), dry matter (%) and dry mass production (%) as well as basic nutritional characteristics by the two swaths of the tested cultivars in brooming phase were controlled. It was found that the sweet sorghum cultivar “Shumensko sladko” gave the highest amount of green mass – 59.5 t/ha by two swaths, and the dry mass yield was the highest from the cultivar Endje 1 – 20.8 t/ha. In terms of chemical composition, the greatest variation was demonstrated in phosphorus content (0.369-0.696%, CV=27.3%), followed by crude fat (1.28-2.39%, CV=26.8%), Ca (0.889-1.572%, CV=21.8%), crude protein (6.05-9.00%, CV=14.6%), nitrogen free extracts (42.05-51.20%, CV=7.6%), crude fiber (32.64-39.26%, CV=6.1%) and mineral substances (8.17-9.61%, CV=5.9%). It can be summarized that all hybrids provide quality hay, however the Bulgarian cultivars Endje 1 and “Shumensko sladko” showed the best nutritional value – compared to Super Sweet, Vercors, SWT and “Zaharna metla”.

Influence of long-term fertilization and environments on test weight of durum wheat (Triticum durum Desf.) grain

G. Panayotova1*, S. Kostadinova2, S. Stefanova-Dobreva3, A. Muhova3

1Department of Plant production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Agrochemistry and Soil Science, Faculty of Agronomy, Agricutural University, 4000 Plovdiv, Bulgaria
3Field Crops Institute, 6200 Chirpan, Bulgaria

(Manuscript received 6 September 2020; accepted for publication 26 February 2020)

Abstract. The aim of this study was to investigate the influence of long-term nitrogen-phosphorus fertilization and meteorological conditions during the period 1990-2019 on test weight of durum wheat grain in Central South Bulgaria. The influence of nitrogen and phosphorus rates – 0, 40, 80, 120 and 160 kg.ha-1, as well as combined NP fertilization in the same rates on durum wheat grain under conditions of stationary long-term fertilizing experiment in cotton-durum wheat crop rotation was studied. The analysis of the results showed that the test weight was below the standard requirements in eight of the studied years, and in 22 years the average test weight exceeded the requirements. The values in 17 years were over 80.0 kg. The test weight decreased by increasing the N rates above 80 kg and the lowest average value was seen at N160 – 79.4 kg. The Р application in rates from 40 tо 160 kg.ha-1 indicated a tendency to increase the test weight. Good values were realized by combining a moderate to high phosphorus rates Р80-160 with low N levels N40-80. Weather conditions during the 30-year period have a strong significant impact on the test weight of the grain.

Vulnerability of sweet cherry cultivars to continuous periods of spring frosts in Plovdiv, Bulgaria

S. Malchev, S. Savchovska*

Fruit Growing Institute – Plovdiv, 12 Ostromila Str., 4004 Plovdiv, Bulgaria

(Manuscript received 31 August 2020; accepted for publication 16 October 2020)

Abstract. The periods with continuous freezing air temperatures reported during the spring of 2020 (13 incidents) affected a wide range of local and introduced sweet cherry cultivars in the region of Plovdiv. They vary from -0.6°C on March 02 to -4.9°C on March 16-17. The duration of influence of the lowest temperatures is 6 and 12 hours between March 16 and 17. The inspection of fruit buds and flowers was conducted twice (on March 26 and April 08) at different phenological stages after continuous waves of cold weather conditions alternated with high temperatures. During the phenological phase ‘bud burst’ (tight cluster or BBCH 55) some of the flowers in the buds did not develop further making the damage hardly detectable. The most damaged are hybrid El.28-21 (95.00%), ‘Van’ (91.89%) and ‘Bing’ (89.41%) and from the next group ‘Lapins’ (85.98%) and ‘Rosita’ (83.33%). A larger intermediate group form ‘Kossara’ (81.67%), ‘Rozalina’ (76.00%), ‘Sunburst’ (75.00%), ‘Bigarreau Burlat’ (69.11%) and ‘Kuklenska belitza’ (66.67%). Candidate-cultivar El.17-90 ‘Asparuh’ has the lowest frost damage values of 55.00% and El.17-37 ‘Tzvetina’ with damage of 50.60%.

Species composition and density of weeds in a grain maize crop depending of soil tillage

P. Yankov*, M. Drumeva

Department of Plant Production, Faculty of Manufacturing Engineering and Technologies,
Technical University of Varna, 1 Studentska Str., 9010 Varna, Bulgaria

(Manuscript received 5 September 2020; accepted for publication 26 October 2020)

Abstract. The study was carried out during 2014-2016 on slightly leached chernozem soil type. The species composition and density of weeds were studied in grain maize grown after previous crop wheat under the following main soil tillage types: ploughing at 24-26 cm, chisel plough at 24-26 cm and no-tillage (direct sowing). The additional tilths of the areas with ploughed and loosened soil included single disking in autumn and double pre-sowing harrowing in spring. A total herbicide was applied for control of the emerging weeds in the variant with direct sowing. The weed control was done according to the standard technology for growing of the crop in this region – treatment with herbicides at stage 3rd-5th leaf of the plants. Weed infestation was read in spring prior to the pre-sowing tillage, immediately before the vegetation treatment with herbicides, and after harvesting. The type of main soil tillage had a statistically significant effect on the species composition and the density of weeds in the grain maize crops grown after previous crop wheat. The use of ploughing, in parallel with the use of chemicals for weed control, decreased the weed infestation in the maize crops. The lower density of weeds under this main soil tillage type was related to changes in the composition and the relative percentage of the respective species in the total infestation. The use of tilths without turning the surface layer and no-tillage in the crop rotation, in spite of the application of herbicides, contributed to the increase of the amount of weeds. The reason for this was the higher variability of weed species typical for shallow tillage types.

Effects of location, gender and indole butyric acid on rooting of Laurus nobilis L. semi-hardwood stem cuttings

A. Saeed*, T. Amin

Department of Environment and Forestry, Faculty of Agriculture, Tishreen University, Latakia, Syria

(Manuscript received 15 April 2020; accepted for publication 1 July 2020)

Abstract. The research was conducted in 2018 in order to investigate the effect of location, tree gender and indole butyric acid (IBA) 4000ppm on rooting of semi-hardwood stem cuttings. Two locations (Al-Samrah and Al-Nabaeen) in Latakia province, Syria, different in latitude and above sea level (500 m and 827 m, respectively) were studied. The results showed significant effect (p<0.05) of the location and tree gender on rooting capacity. No rooting was observed in control (without IBA treatment). Location also affected the number of roots/cuttings. No effect of location or tree gender on root length and diameter was established. The highest rooting rates (%) were for cuttings taken from female trees from Al-Samrah location when treated with IBA 4000 ppm (82.2%).