Nutritional Amendments Research Articles

Review on rewiring of microalgal strategies for the heavy metal remediation - A metal specific logistics and tactics

Phycoremediation of heavy metals are gaining much attention and becoming an emerging practice for the metal removal in diverse environmental matrices. Still, the physicochemical state of metal polluted sites is often found to be complex and haphazard in nature due to the irregular discharge of wastes, that leads to the lack of conjecture on the application of microalgae for the metal bioremediation. Besides, the foresaid issues might be eventually ended up with futile effect to the polluted site. Therefore, this review is mainly focusing on interpretative assessment on pre-existing microalgal strategies and their merits and demerits for selected metal removal by microalgae through various process such as natural attenuation, nutritional amendment, chemical pretreatment, metal specific modification, immobilization and amalgamation, customization of genetic elements and integrative remediation approaches. Thus, this review provides the ideal knowledge for choosing an efficient metal remediation tactics based on the state of polluted environment. Also, this in-depth description would provide the speculative knowledge of counteractive action required for pass-over the barriers and obstacles during implementation. In addition, the most common metal removal mechanism of microalgae by adsorption was comparatively investigated with different metals through the principal component analysis by grouping various factor such as pH, temperature, initial metal concentration, adsorption capacity, removal efficiency, contact time in different microalgae. Conclusively, the suitable strategies for different heavy metals removal and addressing the complications along with their solution is comprehensively deliberated for metal removal mechanism in microalgae.

How can leaf-litter from different species growing in short rotation coppice contribute to the soil nutrient pool?

Quantifying leaf-litter and the potential contribution of essential nutrients to the soil is key to guaranteeing the sustainability of forest systems, especially in plantations under short rotation coppice, insofar as it can condition crop management such as the requirement for nutritional amendments. Nutrient cycling is dependent on production as well as litter decomposition, so to compare the different strategies of the species in nutrient recycling it is important not only to determine the quality and quantity of leaf litter, but also the decomposition rate dynamics and the consequent potential incorporation of organic matter and nutrients into the soil. Therefore, this work aims to quantify and analyze the dynamics of leaf-litter as well as the retranslocation rate, to assess the decomposition rate of the foliar biomass and its nutrient concentrations, and finally, to assess the evolution of leaf-litter quality.For these purposes, eight genotypes were considered in this study: Populus deltoides (‘Baldo’), Populus × canadensis (‘Ballottino’, ‘I-214′, ‘Orion’ and ‘Oudenberg’); Platanus × hispanica (‘Girona’), Salix matsudana × Salix spp. (‘Levante’) and Robinia pseudoacacia (‘Nyirsegi’). The plantation was established in central Spain with a density of 10,000 cuttings ha−1. Three rotations of 3 years each were applied, this study being carried out during the first growing season of the second rotation.Although the leaf fall dynamics were similar among the different species, the production and quality of the leaf-litter were highly species specific. Different strategies were identified; greater retranslocation of N and P being found in poplar, plane tree or only of P in the case of black locust as a conservation strategy, although lower retranslocation of all nutrients was observed in willow, which means that the leaf litter of the latter is very rich in nutrients. While willow, black locust or even some genotypes of poplar are capable of releasing many of the nutrients to the soil during decomposition, plane tree released a smaller variety of nutrients, N, P and Mg being immobilized in the leaf-litter.From the perspective of conserving the soil fertility resulting from the decomposition of leaf-litter, the plantations of species with the highest decomposition rates, such as black locust and willow, were found to be the most recommendable. However, the immobilization of some nutrients in the leaf-litter during the decomposition process could satisfy the nutritional requirements of these species in the medium and long term, thus an advantageous strategy could be to mix species with different decomposition dynamics.

Architectural Responses of Cashew to Intercropping and Nutritional Amendments in Nigerian Guinea Savanna Agro Ecology

Field experiment was conducted at Cocoa Research Institute of Nigeria sub-station Ochaja, to evaluate the impact of manure and intercrops on cashew tree growth, canopy development and yield. Treatments consisted of Bambara and Sesame intercrops and manuring using Cocoa pod husk (CPH) and NPK fertilizer applied at the rate of 0, 1,713kg and 400kg/ha respectively. The experiment was laid out in a split-split plot design with three replications and monitored within the two years of study. Data collected includes: Plant height, Stem girth and canopy North-South/East-West direction. These was used to calculate: crown diameter, canopy spread, canopy volume, canopy ground cover and canopy ground cover percentage. The results showed that the growth characters of Cashew were positively influenced by alley crops of Sesame and Bambara nut and manuring. Manuring with CPH exerted differences in the responses of cashew to alley crops, in particular, canopy development. Intercropping with a combination of bambara-sesame and the application of NPK fertilizer proved to have the highest Cashew growth development but showed no significant differences on the yield and yield attribute. The GGE biplot results identified the best intercrop system for each of the three-fertilizer type treatment. Within the two years of the experiment, Cashew development was not hampered by the introduction of the different intercropping systems.

Copper accumulation and physiological markers of soybean (Glycine max) grown in agricultural soil amended with copper nanoparticles

Copper-based nanoparticles (NPs) display a strong potential to replace copper salts (e.g., CuSO4) for application in agricultures as antimicrobial agents or nutritional amendments. Yet, their effects on crop quality are still not comprehensively understood. In this study, the Cu contents in soybeans grown in soils amended with Cu NPs and CuSO4 at 100–500 mg Cu/kg and the subsequent effects on the plant physiological markers were determined. The Cu NPs induced 29–89% at the flowering stage (on Day 40) and 100–165% at maturation stage (on Day 100) more Cu accumulation in soybeans than CuSO4. The presence of particle aggregates in the root cells with deformation upon the Cu NP exposure was observed by transmission electron microscopy. The Cu NPs at 100 and 200 mg/kg significantly improved the plant height and biomass, yet significantly inhibited at 500 mg/kg, compared to the control. In leaves chlorophyll-b was more sensitive than chlorophyll-a and carotenoids to the Cu NP effect. The Cu NPs significantly decreased the root nitrogen and phosphorus contents, while they significantly increased the leaf potassium content in comparison with control. Our results imply that cautious use of Cu NPs in agriculture is warranted due to relatively high uptake of Cu and altered nutrient quality in soybeans.

Evaluation of nutritional amendments and fungicides against brown leaf spot of rice

Helminthosporium oryzae, the causal organism of bacterial leaf spot (BLS) has brought a tremendous loss of rice crop in the field. Rice seedlings of four commercial varieties (Nayab basmati, Kiran 434, Super basmati, and Pak 386) were screened against BLS in the field by using a randomized complete block design (RCBD). The present experiment was encompassed the evaluation of fermented farmyard manure, leaf manure, Boron, and NPK solution against BLS. The effect of different fungicides (Score, Flumax, Melodyduo, and Polyram) was also checked on the mycelial growth of Helminthosporium oryzae in-vitro and in-vivo. The results showed that Pak 386 was highly resistant with 17.22% disease severity and Super Basmati was found moderately resistant with 22.31% disease severity; variety Kisan 434 was found moderately susceptible (24.15%) and Nayab Basmati (24.82%) was susceptible. Among all NPK solutions showed the best results in growth enhancement, plant vigor as well as reduction in disease severity followed by FFYM, boron and leaf manure. Under in-vitro conditions, all the fungicides performed best at 150 ppm in terms of colony growth reduction. The maximum growth inhibition was recorded in Score followed by Flumax, Melodyduo, and Polyram. Score gave a significant reduction in BLS disease severity and maximized the agronomic attributes. The fungicides performed best at 150 ppm in terms of colony growth reduction. The maximum growth inhibition was recorded in Score followed by Flumax, Melodyduo, and Polyram. Score gave a significant reduction in BLS disease severity and maximized the agronomic attributes. Keywords: HBV, HCV, ICT, PCR, Risk factors, Mansehra

(IMCS Second Place Best Paper Winner) Investigation of Room Temperature Ionic-Liquid (RTIL) Modified Electrode for Decoupling Soil Electrochemistry

Room temperature ionic liquid (RTIL) is a unique zwitter-ionic compound, that possesses excellent physical and chemical properties, which enables electrochemical applications such as to be utilized as a transducer for probing a complex matrix such as soil. The wide electrochemical window and elevated double layer capacitance of RTIL helps to gauge soil parameters which is helpful to understand soil state. In this work we investigate the utility of RTIL modified electrodes as viable sensors for decoupling soil electrochemistry. Soil plays the key role in plant and crop production and is a vital parameter in the ecological structure of the planet and indispensable in the food ecosystem cycle. Soil health monitoring in the near past has been highly qualitative and speculative with more recent advancements still trying to fill the void of a holistic soil profile. In fields and crop-circles, testing methods to perform in-situ profiling however from one lab is likely to vary with another and hence results are not universally compatible. Additionally, these normalized techniques ideally involve empirical approaches, extensive sample preparation which adds on to a temporal factor along with equipment for extraction and subsequently-analysis. This therefore-stimulates the need for a testing methodology that is capable of rapid analysis in an in-situ environment that can be applicable universally.In this paper, we focus on: a rapid electrochemical point probing mechanism that acts as a soil state evaluation platform via a 3-electrode sensor modified by a widely characterized-RTIL [BMIM] [BF4] interfacial transducer medium. The proposed quantitative model –‘DENSE’ probes the soil diffuse double layer (DDL) dielectric to evaluate a thorough chemical profile of the soil matrix. The experimental design was implemented to capture the effect of electroactive species in the soil matrix altered by adding nutritional amendments. Non-faradaic probing was then performed in this design to gauge the inherent capacitive modulations of the soil system as a function its compositional changes. Therefore, by looking at the rate of electrochemical activity and inherent soil dielectric changes driven by an RTIL interfacial layer, it is possible to decouple information on nutrient availability in soils with potential for application towards temporal soil analysis.Figure: (A) Equivalent-circuit (DENSE) model of the soil-water matrix and a schematic representation of the model with respect to the electrode-electrolyte interface (B) Impedance nyquist plot and (C) Bode-phase to denote the pseudo-capacitive dominant nature of the soil matrix (1:1, 1:2) and the comparatively resistive behavior of the baseline and 2:1 mixture Figure 1

Evaluation of fungicides and nutritional amendments against powdery mildew of pumpkin

Evaluation of fungicides and nutritional amendments against powdery mildew of pumpkin

Effect of different cereals flour additives on sporophores production of Oyster mushroom (<em>Pleurotus sapidus </em>and<em> Pleurotus flabellatus</em>)

Oyster mushroom (Pleurotus sapidus and Pleurotus flabellatus) was observed for production with application of nutritional amendments to the substrates. In present study cereals additives are evaluated for the impact on yield and quality of oyster mushroom. Maximum number (57.75) of sporophore was observed with maximum yield (723.75g/kg of dry substrate with 72.37% B.E.) sporophore in wheat straw + Rice flour @2.5%. The minimum yield was found in control (without additive) (540.00g/kg of dry substrate with 54% B.E.) in Pleurotus sapidus whole. In case of Pleurotus flabellatus maximum number of sporophore (76.25) and maximum yield (866.25g/kg of dry substrate with 72.37% B.E.) was found in wheat straw + Rice flour @2.5%. The minimum yield was found in control (without additive) (579.00g/kg of dry substrate) which was found significantly lower than all treatments.

Effect of Macrophomina phaseolina, organic manure and spent engine oil on Luffa aegyptica (Mill)

There is an increasing environmental concern over improper disposal of spent engine oil (SEO) from serviced engines. These concerns are the results of increasing pollution of the environment by SEO with its negative consequences on plants and other forms of life. The present study assessed the effect of Macrophomina phaseolina and nutritional amendment on Luffa aegyptiaca grown on spent engine oil polluted soil in a screen house. The effect of SEO and nutritional amendment on L. aegyptiaca was assessed on germination, plant height, leaf area, stem girt and number of leaves. Two concentrations of SEO (100 and 200ml) in four kilogram of soil were used in four replications each. Results show that SEO adversely affected the germination and growth of L aegyptiaca as delayed germination, reduction in heights, leaf area and number of leaves were observed in the crop planted in SEO polluted soil. Germination (emergence) of L. aegyptiaca seeds planted in SEO polluted soil began after four days compared to two days for plants in untreated soil. Germination efficiency for seeds planted in unpolluted soil was up to 100% but reduced to 20% when the soil was polluted with SEO. However, nutritional amendment and M. phaseolina increased seed germination in SEO polluted soil from 20% to 60%. Nutritional amendment and M. phaseolina were thus shown to enhance the germination and growth of L. aegyptiaca in SEO polluted soil.Keywords: Macrophomina phaseolina, Luffa aegyptiaca, Germination, Effect, Spent engine oil

EVALUATION OF NUTRITIONAL AMENDMENTS, PLANT EXTRACTS AND CHEMICALS FOR THE MANAGEMENT OF STEM ROT OF RICE

Rice is the staple food of more than one third of world population. The emerging threat to this crop is the stem rot of rice. It is one of the dangerous disease causing huge losses to rice crop worldwide. In-vitro experiments were performed for evaluation of three plant extracts (Eucalyptus globules, Azadirachta indica and Alstonia scholaris) was done at three concentrations (10%, 5% and 2.5%) by poison food technique against the causal fungus, Sclerotium oryzae. Eucalyptus extract was found the most effective followed by neem and devil. Similarly, three fungicides, Thiophenate methyl 70% WP, Difenoconazole 10% WDG and Azoxystrobin 50% WDG were also tested at three concentrations (R, R/2 & R/4) and among these Thiophenate methyl 70%WP was the most effective followed by Difenoconazole 10% WDG and Azoxystrobin 50% WDG. The field trial based on 11 treatments comprising of organic nutritional amendments, plant extracts and fungicides was conducted using RCBD. It revealed that mixture of all organic nutritional amendments in combination with Thiophenate methyl fungicide showed significant response in the reduction of disease incidence. Moreover, these amendments also improved the plant growth and yield parameters i.e. plant height, panicle length (cm), number of tillers per plant, number of kernels per panicle, 1000-grain weight and yield/plant.

Post-plant strategies for management of black root rot-related decline of perennial strawberry fields

Perennial strawberries affected with black root rot generally decline in runner production, yield, and overall plant vigor over time. Several plant pathogens have been implicated in black root rot, including plant-parasitic nematodes, Pythium and Rhizoctonia spp. Pre-plant treatments such as a 3- to 5-year crop rotation or chemical fumigation are the main means of disease management. During 2007 and 2008, five post-plant treatments were evaluated for mitigation of strawberry black root rot in a naturally declining site in Ottawa County in Michigan. Fungicides and nutritional amendments were applied as drenches or foliar sprays. Most treatments increased runner establishment, yield, and overall plant vigor, particularly azoxystrobin and azoxystrobin + potassium phosphite. Root necrosis and incidence of root infection by binucleate Rhizoctonia spp. were reduced. Results were more apparent and significant in 2008 than in 2007, indicating cumulative effects over the 2 years of the trial. During 2008 and 2009, a large-scale demonstration trial was conducted with these treatments in a strawberry field with a history of black root rot in Leelanau County, MI. Improvements in bed fill and average plant weight and reductions in root necrosis and Rhizoctonia isolations were noted. This research represents the first post-plant chemical management strategy capable of slowing or even reversing the decline due to black root rot in established strawberry fields.

Management of Fusarium wilt of chilli caused by Fusarium oxysporum f. sp. capsici through nutritional amendments under greenhouse conditions

Management of Fusarium wilt of chilli caused by Fusarium oxysporum f. sp. capsici through nutritional amendments under greenhouse conditions

Management of Cotton Leaf Curl Virus Disease and its Vector through In Vivo Evaluation of Organic Nutritional Amendments, Organic Oils and Insecticides

Cotton (Gossypium hirsutum L.) is the most important cash crop having a great agro-economic significance throughout the world. Cotton leaf curl virus (CLCuV) is the most devastating pathogen of cotton, which is responsible for causing huge economic yield losses. The present study was focused on the application of organic nutritional amendments (farm yard manure, spent compost, decomposed leaves compost and kitchen waste compost) in the soil for the enhancement of plant vigor as well as for increasing the ability of plants to survive against the viral attack. The applications of organic oils (canola, sunflower and cotton seed) were done at 25% concentration (25% oil and 75% vinegar) on young cotton plants in order to create hurdle against insect vector infestation (Bemisia tabaci Genn.) and insecticides (Imidiacloprid (Imidacloprid 25% WP), Megamos (Acetamparid 20% SC and Bifenthrin (Bifenthrin 10% EC)) were sprayed at their standard doses in the field for maximum mortality of whitefly (Bemisia tabaci Genn.) with 7 days interval. The trial was conducted at the research area of Department of Plant Pathology, University of Agriculture, Faisalabad under randomized complete block design (RCBD) with three replications. The recorded data was subjected for analysis of variance (ANOVA) and the means were compared using least significance difference (LSD) test.

Copper nanoparticle (CuNP) nanochain arrays with a reduced toxicity response: a biophysical and biochemical outlook on Vigna radiata.

Copper deficiency or toxicity in agricultural soil circumscribes a plant's growth and physiology, hampering photochemical and biochemical networks within the system. So far, copper sulfate (CS) has been used widely despite its toxic effect. To get around this long-standing problem, copper nanoparticles (CuNPs) have been synthesized, characterized, and tested on mung bean plants along with commercially available salt CS, to observe morphological abnormalities enforced if any. CuNPs enhanced photosynthetic activity by modulating fluorescence emission, photophosphorylation, electron transport chain (ETC), and carbon assimilatory pathway under controlled laboratory conditions, as revealed from biochemical and biophysical studies on treated isolated mung bean chloroplast. CuNPs at the recommended dose worked better than CS in plants in terms of basic morphology, pigment contents, and antioxidative activities. CuNPs showed elevated nitrogen assimilation compared to CS. At higher doses CS was found to be toxic to the plant system, whereas CuNP did not impart any toxicity to the system including morphological and/or physiological alterations. This newly synthesized polymer-encapsulated CuNPs can be utilized as nutritional amendment to balance the nutritional disparity enforced by copper imbalance.

Effect of nitrogen concentration on lipid productivity and fatty acid composition of Monoraphidium sp.

Green algae, Monoraphidium sp. T4X, was isolated locally, in New Delhi, India and identified as a potential source of biofuel. The study focuses on the effect of nutritional amendments and their uptake rates with respect to growth and change in fatty acid composition of the species. The lipid productivity and fatty acid profile were investigated and compared under six different nitrogen concentrations. Of the tested concentrations, cultures with nitrate concentration 0.36 g/l exhibited higher lipid productivity (0.18 g/l/day) with optimum content of all fatty acid compositions (SFA=37.22, MUFA=39.19, PUFA=23.60) with appropriate biodiesel properties. The right phase for harvesting microalgae was also investigated on the basis of the growth curve.

A new computational control strategy for leachate management in bioreactor landfills

A novel computational measurement-based control strategy (CMCS) was developed to manage leachate recirculation based on monitoring of key system parameters. The proposed framework identifies the operational phase of the controlled bioreactor, and accordingly determines quantities of leachate, buffer, supplemental water, and nutritional amendments required to provide the temporally changing landfill microbial consortia with their growth requirements. The CMCS was tested in a pilot-scale bioreactor cell (0.5 m3) for a period of nine months, and compared to a conventional open-loop leachate control scheme (fixed recirculation rate of produced leachate) in an identical cell. Overall, positive results confirmed the applicability and benefits of the control strategy to optimize the leachate recirculation and manipulation processes. Throughout the 21 operational cycles of the controlled bioreactor cell, the maximum specific daily recirculation volume (24 L/t/d) was sixfold the minimum volume determined. The amounts of inoculum/nutrient, buffer, and supplemental water were also computed cyclically, and ranged between 2% and 11%, 1% and 9%, and 3% and 16% of the total volume recycled, respectively. The recirculated volumes of leachate and other amendments were highly variable, and did not follow any predictable trends. In general, CMCS achieved proper control with a minimal use of resources, e.g. it utilized about 55% less buffer compared with the leachate neutralization practice commonly used in lab- and pilot-scale studies. The greater degradation rates of organic matter combined with relative increases in biogas production (1.7-fold greater) demonstrate that calculation-based recirculation stimulated the methanogenic activity and accelerated the bioreactor evolution.

Promoting Forest Recovery on a Surface Mine Site With Nutritional Amendments

Selected nutrient amendments were evaluated for their capacity to enhance growth and nutrition of Jeffrey pine (Pinus jeffreyi Grev. & Balf.) seedlings 3 yr after planting on an acidic Sierra Nevada surface mine. The amendments were applied by topdressing at four rates each and consisted of Forestcote 22-4-6 + Minors, a controlled release formulation; Free Flow 29-3-4 and Hydro Agri 21-7-14, two conventional fertilizers with the former featuring urea as the predominant N source while that for the latter was exclusively ammoniacal and nitrate forms; and Milorganite 6-2-0 + Iron, an organic amendment derived from municipal biosolids. The Forestcote and Free Flow formulations proved most adept at reinvigorating seedling growth while Hydro Agri and Milorganite were the least stimulatory. The lowest application rates employed were inadequate but the most advantageous rate differed somewhat by formulation. Foliar analysis revealed that fertilized seedlings had more N and P but less Mn and Al than the control. Enhanced N nutrition especially, but also that of P, probably accounted for most of the growth stimulation by the amendments, as availability of both in the soil was limiting. Of the two metallic elements, reduced Mn was likely most critical because concentrations encountered here were exceedingly elevated overall, including that in the soil, although soil Al was high also. These results suggest that a variety of nutritional amendments can be employed in forest restoration on surface mine sites and those similarly degraded, including sites for which dry climates greatly influence the selection of remedial practices.

Enteric methane mitigation technologies for ruminant livestock: a synthesis of current research and future directions

Enteric methane (CH(4)) emission in ruminants, which is produced via fermentation of feeds in the rumen and lower digestive tract by methanogenic archaea, represents a loss of 2% to 12% of gross energy of feeds and contributes to global greenhouse effects. Globally, about 80 million tonnes of CH(4) is produced annually from enteric fermentation mainly from ruminants. Therefore, CH(4) mitigation strategies in ruminants have focused to obtain economic as well as environmental benefits. Some mitigation options such as chemical inhibitors, defaunation, and ionophores inhibit methanogenesis directly or indirectly in the rumen, but they have not confirmed consistent effects for practical use. A variety of nutritional amendments such as increasing the amount of grains, inclusion of some leguminous forages containing condensed tannins and ionophore compounds in diets, supplementation of low-quality roughages with protein and readily fermentable carbohydrates, and addition of fats show promise for CH(4) mitigation. These nutritional amendments also increase the efficiency of feed utilization and, therefore, are most likely to be adopted by farmers. Several new potential technologies such as use of plant secondary metabolites, probiotics and propionate enhancers, stimulation of acetogens, immunization, CH(4) oxidation by methylotrophs, and genetic selection of low CH(4)-producing animals have emerged to decrease CH(4) production, but these require extensive research before they can be recommended to livestock producers. The use of bacteriocins, bacteriophages, and development of recombinant vaccines targeting archaeal-specific genes and cell surface proteins may be areas worthy of investigation for CH(4) mitigation as well. A combination of different CH(4) mitigation strategies should be adopted in farm levels to substantially decrease methane emission from ruminants. Evidently, comprehensive research is needed to explore proven and reliable CH(4) mitigation technologies that would be practically feasible and economically viable while improving ruminant production.

Advancing Forest Cover Development on a High‐Elevation Sierra Nevada Mine Site with Nutritional Amendments

Abstract Selected nutrient amendments were evaluated for their capacity to enhance growth and nutrition of established but stunted Jeffrey pine (Pinus jeffreyi Grev. & Balf.) saplings on an acidic Sierra Nevada surface mine. The amendments were applied by topdressing at three rates each and consisted of Forestcote 22‐4‐6 + Minors, a controlled‐release formulation; Free Flow 29‐3‐4 and Hydro Agri 21‐7‐14, two conventional fertilizers, with the former featuring urea as the predominant N source, whereas that for the latter was exclusively ammoniacal and nitrate forms; and Milorganite 6‐2‐0 + Iron, an organic amendment based on municipal biosolids. All formulations reinvigorated sapling growth, generally more so as the amounts supplied increased, with the Free Flow and Hydro Agri amendments marginally more stimulative than Forestcote and Milorganite. Foliar analysis revealed that fertilized saplings had more N, with concentrations that generally rose with amounts supplied, and P but less Mn and Al than the control. Enhanced N nutrition in particular but also that of P probably accounted for most of the growth stimulation by the amendments, as availability of both in the soil was limiting. Of the two metallic elements, reduced Mn was likely most critical because concentrations encountered here were exceedingly elevated overall, including that in the soil, although soil Al was also high. These results suggest that a variety of nutritional amendments can be employed in forest restoration on surface mine sites and those similarly degraded, including sites for which dry climates greatly influence the selection of remedial practices.

Laboratory study on the bioremediation of diesel oil contaminated soil from a petrol station

The purpose of the present study was to investigate possible methods to enhance the rate of aerobic biodegradation of hydrocarbons (ex-situ treatments). In this work, the bioremediation processes were applied to a sandy soil with a high level of contamination originated from the leakage of a diesel oil underground storage tank at a petrol station. Laboratory scale experiments (Bartha biometer flasks) were used to evaluate the biodegradation of the diesel oil. Enhancement of biodegradation was carried out through biostimulation (addition of nitrogen and phosphorus solutions or Tween 80 surfactant) and bioaugmentation (bacterial consortium isolated from a landfarming system). To investigate interactions between optimizing factors, and to find the right combination of these agents, the study was based on full factorial experimental design. Efficiency of biodegradation was simultaneously measured by two methods: respirometric (microbial CO2 production) and gas chromatography. Acute toxicity tests with Daphnia similis were applied for examination of the efficiency of the processes in terms of the generation of less toxic products. Results showed that all bioremediation strategies enhanced the natural bioremediation of the contaminated soil and the best results were obtained when treatments had nutritional amendment. Respirometric data indicated a maximum hydrocarbon mineralization of 19.8%, obtained through the combination of the three agents, with a total petroleum hydrocarbons (TPH) removal of 45.5% in 55 days of treatment. At the end of the experiments, two predominant bacteria species were isolated and identified (Staphylococcus hominis and Kocuria palustris).