المستودع المؤسسي الرقمي لجامعة عمر المختار

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  Item type: المادة ,

  الفقد الكتلي والتغير في تركيز المغذيات خلال تحلل أوراق أشجار الصنوبر الحلبي النامية في ترب الجبل الأخضر

  (جامعة عمر المختار, 2009-07-20) الزوي, فرج

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  The aims of the present study were to determine Mass loss (ML%) and the changes patterns of Holocellulose (cellulose , hemicelluloses) , Lignin (Non- hydrolysable Residues; NHR), water and Ethanol- Solubles as well as the dynamics of N, P, Na , K , Ca , Mg , Mn , SO4, NO3. The concentration of N in Lignin C:N , Lignin:N and C:P were also determined .The influence of site properties on these parameters (Responses) were evaluated. To achieve these aims , the litter bag technique, which is a wellknown tool for the study of litter decomposition, was applied using bags of 10X10 cm dimentions and with 1mm diameter. The required numbers of the bags were fixed on the bottom of each Aleppo pine (Pinus halepensis Mill.) stands grown in three sites located at 410, 630, and 860m. a. s. l. of the Jabal Alakhdar eco- region, Libya by using a split design system in Four plots. The experiments started in 1.10.2006 and conducted for 18, 10 and 7 months the latter 2 plots Located at 860 m. a. s. l. The data obtained were statistically assessed using ANOVA, Correlation and Regression analysis. The ML (%) values were ca 25, after 7 months of decomposition with significant differences (P.0.05); after 10 months, these values increased to 31% in the stands located at 410 and 630 m. a. s. l. and both were significantly differed with (P.0.05) compared to the stands located at 860 m. a. s. l (ML of ca 20%) . ML Values reached 60% and 43% after 18 months in stands located at 410 and 630 m. a. s. l. respectively and were significantly differed (P.0.05); the water- and ethanol-solubles were significantly differed and decreased from ca 14% and 25% to ca 10% and 18% after 18 months of incubation (decomposition). However, the lignin (NHR) increased from 32 to 38% at both sites, whereas the holocelluloses increased from 27% to 33 and 29% respectively. The total concentration of carbon decreased from 48 to 46 % in both sites and this means that the loss of carbon did not exceed 2% after one and half year of decomposition and consequently the emission of CO2 was low under such pine forest systems. On the other hand, the total N increased up to 1.1 % confirming the fact of the chemical combination of nitrogen (as NH3) to the aromatic rings exposed during the biodegradation of lignin. Total phosphorus decreased from 0.23 to 0.1 and 0.07% in sites located respectively at 410 and 630 m. a. s. l. and no changes of total potassium were observed in both sites. Negative and positive r values between some responses were observed (P.0.05) and some values of R2 above ca 60 % were also noticed. Finally, it is of highly importance to wisely expand the area of Aleppo pine plantations in the bared localities spread in this eco-region. This is for increasing the contribution of such pin forest systems of carbon dioxide capturing and retarding its emission to the atmosphere of our green and fragile planet to reduce the tragedy of the global warming phenomenon.

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  وجود بكتيريا الكبريت في ترب داعمة للعرعر والبطوم تحت ظروف الجبل الأخضر-ليبيا

  (جامعة عمر المختار, 2017-05-02) بوبكر, مفتاح

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  The aims of this study were to determine the persistence of the sulphur oxidizing bacteria in different decomposition stages "the humus layer" and in the soils supporting the (Juniperus phoenicea L and Pistacia lentiscus L). These bushes covers ca 80%' of the Gabal AlAkhdar eco-region, Libya. In the culturing media, the impacts of the pH, salts, temperature and the production of sulfates from such bacterial isolates were also examined. The least significant difference (LSD, 5%) and Pearson correlations between the variables were done using SPSS. To achieve these aims, two sites contain the two plants were selected in the Settia area located north east of Shahat town at ca 400 masl. From each plant and Rhodoxeralfs soils, composite samples were collected from the humus layers The separation of these stages were carried out according to the morphology of the litters. Soil samples were collected at (0-10 cm) depth. The physical (texture and moisture) and chemical analysis including the total N, P, K, S and sulphates and the total counts of bacteria were done at the lab of soil microbiology, Omar Al Mukhtar University. The bacterial strain grew in the thiosulphate medium during a period of 7-10 days. At pH = 8, colonies in a pure culture were appeared white to light yellow .These chemolithoautotrophic mobile short rod cells were a gram-negative, non-endo-spore forming. Such characteristics indicate that this isolate was a Thiobacillus thioparus.The persistence of T. thioparus in the late stages and in the soils supporting the Juniperus were higher than in the Pistacia. The number of the strain in the Pistacia and Juniperus ranged between 0.15 ×104 to 58 × 104 and 0.16 ×104 to 61 × 104, 0.032 ×104 to 50 ×104 and 5.6 × 104 to 91 in the first and the second sites, respectively. Positive correlations were observed between T. thioparus counts and the P, K, SO4-2 and the total count of the bacteria. Strong negative correlation (p<0.001 and R2 of ca 25%, n=60) with EC. The correlations between total count and pH, and total S were negative of p<0.024 and 0.001, R2 of ca 20 t0 25%, n=60, respectively. The total S positively correlated with R2 of ca 25%. Total S positively correlated with the total P (p<0.001 and R2 of ca 25%. Sulfates positively correlated with EC (p<0.001, R2 of ca 25%, n=60, also it negatively correlated with total N (p<0.006, R2 of 16%, n=60. The optimum effect of temperature (25, 30, 35, 40) on the strain after 7 days of incubation was at 30 C and the minimum was 40C. the effect of For the pH, the optimum and minimum were 8 and 5 and no growth at 4. NaCl, CaCl2 and MgCl2 conc. of ( 0.1, 1, 5 g / L ) showed a detrimental effects comparing with the control the sodium thiosulphate medium Conc. of (0.1,1,2,3,4,5,6,7 g) showed optimum and minimum growth at 5g "control" and 0.1g respectively. The effect of this bacterial strain on pH and sulphate production in the thiosulphate medium after about two weeks of incubation revealed that the pH decreased from 7.8 to 6.4 and by 1.4 (17.95%). Sulfate concentration also increased from 0.03% to 0.05%. The Starkey medium on the other hand, decreased pH values from 7.8 to 4.5 by 3.3 (42.31%) with an increase of 24.36% in the thiosulphate medium. This reflects the impact of the type of sulfuric compound "energy source" in increasing acidity, which confirms the superiority of sulfur element "S8" in recommending the development of this bacterial strain for the purpose of reclamation of the salt affected soils (sodic soils). It was observed that the high acidity does affect the growth of this strain but the growth of such bacterium In vivo differs than the growth In vitro "The Habitat" due to the presence of calcium carbonates ; the limestone 'the bed rock' and many other alkaline ions.

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  تقييم بعض خصائص الترب الساحلية ومصادر مياه الري بمنطقة الحنية – الجبل الأخضر

  (جامعة عمر المختار, 2022-02-22) اجويلي, وجدي

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  Al-Hinya is known as a coastal area and is one of the largest areas of the coastal municipality. It is considered one of the most important agricultural areas in Jabal Al-Akhdar, about 25 km away from the city of Al-Bayda. Al-Henya area is of economic importance because of the crops it produces capable of meeting all the needs of Jabal Al-Akhdar. This makes the soil of the area in a state of depletion of its nutrients or even subject to deterioration as a result of intense pressure on it with fertilizers. Therefore, this area was targeted to monitor the condition of the soil in it and follow it during two different seasons. Forty sites were randomly selected to take soil samples that differ in terms of their proximity and distance from the coast. The samples are located at different altitudes from sea level. A number of wells used by farmers for irrigation were also selected. The study included routine procedures for soil by studying the chemical properties of the soil as well as the chemical properties For irrigation water, and therefore to determine its suitability for irrigation compared to global measurements issued by the US Department of Agriculture), USDA, 1954) and about the Food and Agriculture Organization (FAO, 1985) Chemical analyzes consist in knowing the degree of electrical conductivity "EC", the degree of pH and dissolved ions in addition to the use of many mathematical indicators that included the percentage of sorbed sodium "SAR" and the modified "RSC" and residual sodium carbonate "RSC" in addition to some other mathematical indicators for irrigation water.

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  Item type: المادة ,

  تأثير معدلات الري بمياه الصرف الصحي لمدينة البيضاء بالجبل الأخضر علي خصائص التربة ونمو النبات

  (جامعة عمر المختار, 2009-04-18) المهدي, محمد

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  Fresh water resources are limited in most arid and semiarid regions. Libya is not an exception . Jabal Al-Akhdar north – east of libya, receives the highest annual rainfall in the country, but fluctuation in rainfall coupled with increasing demand for fresh water to meet domestic, agricultural and industrial activities posed serious pressure on groundwater which practically represents the sole source of fresh water in the province . A national strategy to utilize domestic sewage effluent to irrigate some forage crops was implemented early in the 1973's. The strategy was limited to two projects namely, Al-Hadba project near Tripoli and Al-Gawarsha project near Benghazi. Other parts in the country including Jabal Al-Akhdar were not included in this national strategy. The current study was aimed toward evaluating the potential for utilizing the untreated domestic sewage effluent of Al-Bayda city in Jabal Al-Akhdar for irrigation on soil chemical properties and the growth of maize ( Zea mays L.), barley ( Hordeum vulgare L. ) and alfalfa ( Medicago sativa L.) in pot experiment under semi–controlled conditions . The two soils are representing forest soils ( Lithic Rhodoxeralfs ) northern part of Jabal Al-Akhdar and pastoral soil ( Lithic Xeric Haplocalcids) southern part of Jabal Al-Akhdar. Groundwater and the untreated sewage effluent of Al-Bayda city were used for irrigation. Two irrigation levels were evaluated based on plant vegetative and root biomass as well as their nutrient and toxic elements content. Each treatment was imposed in triplicates as in Complete Randomized Block Design (RCBD). The data were analyzed statistically by utilizing the software (Genstat ). The impact of irrigation practices on the chemical properties of the two soils were also evaluated . The results of this study has revealed that sewage water contains good concentrations of essential plant nutrients; including nitrogen, phosphorus, potassium, calcium, magnesium, copper and zinc, In addition some pollutant elements such as nickel and lead. Their concentration of the polluting elements was within the accepted range for agricultural use according to local standards as well as Food and Agriculture Organization ( FAO, 1976) and the United States Environment Protection Agency ( USEPA, 1993 ) guidelines. The wastewater was also chacteristized by its low content of soluble salts . The use of the domestic wastewater affected the two soil’s chemical properties positively even though the time span of this study was limited. A significant increase in available phosphorus, total nitrogen, soil organic matter content and cation exchange capacity was observed. The irrigation with ground water or wastewater caused a marginal change in soil рH and soluble salt contents in the two soils . Results has indicated higher plant root weights were produced by crops included in this study when irrigated with the untreated effluent as compared to groundwater. This seems to enhance plant ability to absorb more water and plant nutrients as well as pollutant ions from the soil, which were further reflected positively on wet and dry weight of vegetative parts of these crops and their contents from nutrients such as phosphorus, potassium and calcium . The use of the untreated effluent for irrigating maize, barley and alfalfa led to an increase in nickel, copper, lead and zinc concentration in the two soils and plants tissues, but their concentrations remained within the local and international permissible limits. The concentrations of pollutant elements were highest in the roots of these plants. This reflects important plant selectivity for absorbing ions, and appreciable control for their translocation to the upper plant parts through accumulation in their root systems. This study indicated that the utilization of untreated domestic effluent of Al-Bayda city even for supplementary irrigation of maize, barley and alfalfa under semi controlled conditions and for one season has resulted in significant increase in weight of the vegetative part production of these crops. Moreover, there is no increase in the concentration of pollutant elements in plant tissues that may pose risks to human or domestic animals were detected. Moreover, the use of this nontraditional water source for irrigation under the prevailed conditions of this study has improved the two soil’s chemical properties. [ It seems imperative to pursue this annovative investigation for further evaluation on long term effects of this water resource under field conditions. The chemical make-up of Al-Bayda domestic effluent appear to be acceptable. This will enhance the potential for its use to improve crop production, combating desertification and rehabilitating rangeland. In addition to improvement of the natural ecosystems distinguishing Jabal Al-Akhdar, the adoption of a well planned strategy in this direction will no doubt result in lifting some of the pressure on the limited fresh groundwater of the region.

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  دراسة تحولات الأسمدة النيتروجينية المضافة لترب المرج والصفصاف بمنطقة الجبل الأخضر

  (جامعة عمر المختار, 2015-06-02) أفكيرين, عمران

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  This study was conducted at two sites area of Green Mountain, represents the first location El-marg area (agricultural research station). The station is located on the longitude (20 50) and latitude (32 28) and at an altitude of 310 m above the surface of the Sea level (4) km east from the city of Elmarg on the coastal road linking Benghazi and El-beda. The second site Assfsaf area (Agricultural Research Station). Located in Assfsaf in the Green Mountain area east of El-beda City on the 20 km distance and the longitude (21 56) and latitude (32 46) and at an altitude of 641 m above the surface of the Sea level. This study aimed to follow up the effect of adding sulfur and nitrification inhibitors on the efficiency and transformations of nitrogen fertilizer in soil and the growth of barley and activity total soil bacteria. To achieve the objectives of this study soil samples from the surface to the depth 20 cm it were collected from the regions of the study Areas, chemical and physical properties of the soil were estimated, and forced the experiments in pots and put in a place of study by the distribution field of design (split plot design for twice) After cultivated of barley plant and irrigation to field capacity even under conditions of semicourt added each planter pots treatments of 80 mg / kg soil of P2O5 fertilizer superphosphate and potassium sulfate K2SO4 as sources of phosphorus, potassium, two weeks before the date of Agriculture. Agriculture has also been added sulfur 2 % in pots prepared for this treatment and mixing it well with topsoil to a depth of 5 cm as well as two weeks before the date of planting. Treatments are two types of nitrogen fertilizer as urea and potassium nitrate were added in two period and two doses 80 mg fertilizer / kg soil. First dose added on the soil surface after 3 weeks of the process of germination and the second dose was added after two weeks after the first dose adding, and treatments included also two types of inhibitors, the first is EDTA compound (Ethylene diamine tetra acetic acid) and the second pesticide Carbofuran were added as a single dose each at 50 mg / kg soil at the same date Add first dose of nitrogen fertilizer. The results of this study showed that significant increase in average fresh and dry weight of shoots to barley plant in soils El-marg and Assfsaf as a result of various treatments compared with soil comparison ranged wet weight of 60.03 g / pot to 98.83 g / pot, while the dry weight of 17.40 to 33.16 g / pot, for comparison sample also notes that significant increase in average total vegetative weight in Carbofuran treatments and treatments for EDTA addition of sulfur in general led to the wet and dry weight increase. Variation in the vegetative barley crop grown in two soils of nitrate anion content NO3- under various treatments inhibitors, fertilizer and sulfur, in general conditions occurred ranged concentration of this anion in the plant from 8.7710 -14.278 ppm, the addition of the concentration of 2% sulfur led to lower average concentration of nitrate in the barley plant compared to the treatments has not added to it as well as the focus was less on the user treatments where Carbofuran from those where the user EDTA. Various treatments led to the high content of the vegetative part of the barley plant from phosphorus element in soils this content ranged from 694.73 to 1083.27 ppm and that the addition of sulfur led to higher plant content of this element. Large variations in barley plant content from the potassium element did not happen in both soils as a result of various treatments. Affected soil content of nitrate anion NO3- by various treatments for inhibitors, sulfur and sources of nitrogen added, and it may range from 8.02 to 14,265 ppm in soils resulted in these treatments to lower average concentration of the anions compared with soil non-treatment, as well the concentration of 2% sulfur resulted by lower average concentration of nitrates compared to non-treated soil with sulfur as the difference between the average concentration of nitrate anion in both soils and after the first and second addition of nitrogen fertilizer was a very highly signification as a result of adding inhibitors compared to non-treated soil. The average pH values decreased in general and in soils when Add 2% sulfur in the presence of potassium nitrate fertilizer more than urea fertilizer. The various treatments have affected of the total bacteria in soils it is noted in general that these treatments led to a decline in preparation compared to the soil is treated and that the addition concentration of 2% sulfur led to decline pubulation bacteria as the inhibitor Carbofuran was high effected where decreasing the pubulation by comparing treatments of EDTA inhibitor.

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