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Agriculture is one of the key economic activities designed to provide food for a growing population. It is expected that 21st-century agriculture will try to reduce the number of fertilizers by using microorganisms, in this category arbuscular mycorrhizas representing a complex set of benefits for plants and ecosystem services. The aim of this paper is to identify the mycorrhizal structures present in the roots of Zea mays. The objectives of the research are: i) are mycorrhizae natively present in the corn root and have a constant presence from the first stages of plant development? and ii) what kind of colonization pattern is characteristic of these roots? Maize has prominent fasciculate roots, and due to its intense branching capacity provides increased biological support for the establishment of mycorrhizal symbionts. Within the fungal structures highlighted, the most prominent were arbuscules and vesicles. Arum-type arbuscules were mostly observed, Paris-type arbuscules being less common in this species. Vesicles have a low frequency in the root cortex. They are present only in the early stages of plant development. Vesicular-arbuscular mycorrhizae are present in the root of the Zea mays plant with a constant presence, without major fluctuations. [ABSTRACT FROM AUTHOR]

Grasslands are the most dynamic ecosystems are characterized by high biodiversity both above-ground and underground. The biggest problem in these ecosystems is oligotrophy. The phenomenon affects the stability and resilience of these ecosystems, increasing the impact of biological processes. The symbiotic relationship between plants and mycorrhizas is a natural option with a great impact on maintaining the high natural value of ecosystems. This article aims rating colonization Festuca rubra, dominant in a mountain grassland ecosystem. Roots were cleared and stained with ink for the detection of mycorrhizas in roots. All root samples were analyzed with an optical microscope for the detection of mycorrhizal structures. The results obtained highlight a main mycorrhizal pattern as well as specific subcategories. Both types of arbuscules were identified: Arum and Paris. The results obtained highlight a main mycorrhizal pattern as well as specific subcategories. Vesicles are structures with a constant lack of consistency, which indicates their fluctuating nature. The mycorrhizal pattern of Festuca rubra as the dominant species in the pratol ecosystem may be the first step towards a more detailed understanding of the fungal strategy as well as the increased importance in the stability of the pratol ecosystem. [ABSTRACT FROM AUTHOR]

The roots of the plants are in contact with a substrate, and biotic and abiotic factors influence their functioning and development. The most known microorganisms associated with plant roots are soil fungi, which are adapted to the soil's living environment, called mycorrhizae. Arbuscular mycorrhizae are the most common of these associations. In agricultural ecosystems, the constant use of technologies has resulted in a progressive reduction of mycorrhizal diversity. Due to this phenomenon, soil presents a lower potential for the development of multilevel hyphal networks which implies reduced connections between all individuals of a single species. Mycorrhizas offer benefits for the host plant, including mineral nutrition, increased drought tolerance, and protection against pathogens. They play a significant role in acquiring the necessary nutrients (especially phosphorus and nitrogen) from soil to their host plants, as these nutrients may have low mobility in most soils. Plants take up phosphorus from soil indirectly through the hyphal network that can reach outside from the root depletion area. Mycorrhizal association increases the accumulation of nitrogen in the plant as a result of the competition of hyphae for the organic mineralized form of this element. [ABSTRACT FROM AUTHOR]

Structures of different AM taxa found in symbiosis with plants can stain from intense to weak after roots preparation for microscopy. Although arbuscules are distinctive features of AM, their overall shape can vary in association with two proliferation types: Arum and Paris. Auxiliary cells and vesicles are not omnipresent. Intraradical hyphae can present divergent types: straight/coiled, with "Y"/"H" connections. According to spore formation, there are five main AM morphotypes. Spore-based species identification takes into account: color, shape, size of spores and sporocarps as well as structures associated with them (cicatrix, pedicel, peridium, sporiferous saccule, sporogenous cell, subtending hypha). Description of subcellular structures of spores targets phenotypic and biochemical properties of layers using Melzer's reagent and morphology of pre-germination structures when present. [ABSTRACT FROM AUTHOR]

Mycorrhiza develop on the surface of the roots and create complex networks of nutrients transport between the hosts. The present paper evaluates the modification of endomycorrhizal parameters in urban grasses due to the distance from the trunk of the trees. Grass samples were harvested from 3 parks. The objective is to identify the area of maximum development of the mycorrhizal network and the spatial stability of the symbiosis. A pattern of mycorrhizal mechanisms can be identified due to human intervention in the ecosystem. In ecosystems, the overhead distance between trees is dominated by grassy species capable of endomycorrhizal connections. Between fungi and plants, connecting nodes and nutrient transfer points appear. Frequency of mycorrhizas in grasses is over 90%. The intensity in root is below 30%, but supported by high arbuscularity. The impact of mycorrhizae is felt only at the time of intense colonization and the presence of arbuscules. [ABSTRACT FROM AUTHOR]

Urban parks are ecosystems with a dynamic directed by human intervention. Arbuscular mycorrhizal fungi are symbionts with higher plants, with role in increasing the amount of nutrients needed to plant development. In roots, the fungi develops various structures for transfer or storage of nutrients. The grasses developed in the parks of the Cluj-Napoca city present typical mycorrhizal structures, including the two morphotypes of arbuscules. The colonization rate identified in the analyzed samples is over 75%, indicating a high number of propagules in soil. The dependence of arbuscles is higher to intensity than colonization frequency. [ABSTRACT FROM AUTHOR]

Microbial groups developed in the rhizosphere ensure the stability and dynamics of nutrient transfer processes to plants. Additional soil inoculation with rhizospheric bacteria acts to expand the ecological niche, supplements the activity, the number of individuals and promote plant growth. In today's agriculture, there is a need for the usage of rhizosphere microflora and integrative approaches to stimulate plant growth. The aim of the study is to evaluate the use of biofertilizers as starter stimulators in autumn wheat. Different concentrations of Bactofil, containing rhizospheric bacteria, were applied in small rhizothrones. Evaluation of relationships between bacterial inoculum and plant reveals the degree of applicability and adaptation to the soil conditions of exogenous microflora. Doses of 15.6 x 108 and 20.8 x 108 cells/m2 stimulates the root elongation and higher level of mycorrhization. Bioproducts can be viable solutions to stimulate the initial development of wheat plants. [ABSTRACT FROM AUTHOR]

Water ecosystems are constantly under the pressure of a high number of biotic and abiotic factors, and their action leads to the occurrence of fluctuations in species and populations. The specific response of organisms to external pressures leads to the reorganization of ecosystems, with qualitative and quantitative changes. The aim is to identify the microbial groups with the highest potential in the waste waters. Data were collected during 2015-16 in Bistrita. Identifying the bioindicators quality of microorganisms and their importance in ecosystems was done by comparing them with international databases. The use of microorganisms as bioindicators involves knowing the requirements for one or more environmental variables. The concept refers to the ability of microorganisms to accumulate pollutants. Flagellates are tolerant to acidity and react quickly and with sensitivity to environmental stress by inhibiting their movement. The multiplication of flagellates and filamentous bacteria is manifested through water disturbance and foam production. [ABSTRACT FROM AUTHOR]

The purpose of this research is to assess the state of the biodiversity and pastoral value for Festuca rupicola-Bothriochloa ischaemum grasslands from the hill area. Also, there has been analyzed the floristic composition and a series of ecological indexes, respectively humidity, soil reaction, temperature and nitrogen. Other aspects taken in account were the agronomical and anthropogenic specters. The analyzed grasslands are placed in the perimeter of the localities: Gilău, Aiton. Jucu and Frata, all from Cluj County. [ABSTRACT FROM AUTHOR]

According to The European Communion in Europe there are large areas of abandoned grasslands (Osterburg and colab., 2010). The abandonment of grasslands entails substantial changes to the vegetation cover. Usually, after a period of time, semi-natural grasslands start to develop forestlike features. In Romania despite the existence of a subsidiary system large areas with semi-natural grasslands are abandoned. The objective of this paper was to analyze the effect of abandonment on the structure of vegetation cover. The experiment consists in 3 experimental variants (1 mowed annually, 1 abandoned for 5 years and 1 abandoned for 15 years) and is located in the village of Ghețari, from Gârda de Sus commune at an altitude of 1130 m. Vegetation was studied using the Braun-Blanquet method, modified by Păcurar and Rotar in 2014. The scientific results were processed with the numerical analysis application (Cluster Analyses) belonging to PC-ORD program. Results showed that the grassland abandoned for 5 years did not show any statistical difference compared to the grassland mowed annually. The grassland abandoned for 15 years showed modification in the structure of vegetation cover translated by the disappearance of numerous species. Our recommendation is that semi-natural grasslands, which have numerous economical disadvantages because of their location, should be mowed at least every five years. [ABSTRACT FROM AUTHOR]

Plant rhizosphere is the portion of soil which is in direct contact with the plant roots. From the microbiological point of view, this area is characterized by strong dynamic of functional groups with high specificity towards the substrate available. Spring barley is a crop with high requirements to the composition of the microflora in the rhizosphere, disturbances produced by agronomic inputs affecting the stability of rhizospheric contact interfaces and ultimately the plant growth. Analysis of changes within the microbial community was carried out with the purpose of defining the disruptive impact of mineral inputs and potential of zeolite to reduce these disruptions. Microbial functional groups were analyzed on the basis of the CO2 export under the specific conditions of soil inoculation on specific substrates over a time period of incubation. Microresp detection plates allow evaluation of a large number of samples under identical conditions of inoculation and the establishment of dynamics of the entire microbial community. The dynamics of the entire microbial communities is stimulated to increase in case of unilateral application of zeolite and zeolite as a buffer for urea fertilization. General growth trend of microbial communities follows proportional the associated application of zeolite with urea. Rhizosphere of barley plants is characterized by α-ketoglutaric acid as dominant group in functional microbial community of all experimental variants analyzed. [ABSTRACT FROM AUTHOR]

Microbial communities in agricultural ecosystems are characterized by a strong dynamic and radical change due to technological inputs applied. Corn is a plant with high requirements for nutrients and an increased potential for activation of specific microbial groups. The aim of this study was to assess the unilateral and synergic effect of zeolite and mineral fertilizers on the development and transformation of microbial functional groups in the rhizosphere of corn. Physiological profile assessment of microbial communities has been carried out on the basis of substrate induced respiration, monitored over a period of 6 hours of incubation. The amount of CO2 registered in Microresp plates represents the activity of functional groups in decomposition of each type of substrate applied. Characteristic groups of microorganisms in maize rhizosphere are capable of decomposing acids: citric, L-malic, oxalic and α-Ketoglutaric. The highest microbial activities were observed in groups of bacteria involved in processes of plant growth promotion and microbial groups with an important role in the processes of denitrification. For the application of urea a triple value of activity of this type of microflora is observed. Functional groups codominant in soils cultivated with corn are specialized in efficient degradation of organic matter and biological crust, zeolite providing the complex substrate necessary for the development of these microorganisms. [ABSTRACT FROM AUTHOR]

Mulching of grasslands was suggested by many that could be a feasible solution for the low productive systems to maintain their natural productivity and floristical diversity, when succesion of woody species is a threatening factor. In this middle-term experiment, we aimed to study the effects of new alternatives in Apuseni Mountains, like mulching and mulching with mineral fertilization, on the floristic structure of the oligotrophic grasslands. The experiment has started in 2009 and we followed the effects of the treatments in the 6th year. The experiment design contains seven variants in five repetitions (randomized blocks) of mowing, mulching and mulching with different doses of fertilizers applied in different time. After six years, the treatments determined no changes in the main grassland type, but significant changes have taken place in the floristic compositions of the variants. The overall effects of the treatments are negative upon the phytodiversity in some of the variants. From this reason these has to be carefully recommended if there are conservational purposes. [ABSTRACT FROM AUTHOR]

Salinity is one of the environmental factors that has a critical influence on the germination of seeds and plant establishment. Salinity affects imbibition, germination and root elongation. However, the way in which NaCl exerts its influence on these vital processes, whether it is through an osmotic effect or a specific ion toxicity, is still not resolved. The objective of this study was to compare the salinity tolerance of two varieties of red clover (Select 2 and Rotrif) and two varietis of alfalfa (Mihaela and Mădălina). In our study we used five salinity treatments 0 (control) (C1), 50 (C1), 100 (C2), 150 (C3) and 300mM NaCl (C4) on normal seeds and seeds inoculated with rhizobia. 100 seeds of each variety used in the study were grown in germinating dishes on filter papers with four replications. The results showed that by increasing of the salinity level, germinated seeds number, root, shoot and seedling length, mean daily germination (MDG) and seedling length vigor index (SLVI) decreased, while daily germination speed (DGS) increased in all studied varieties. Mean germination time increased with increasing NaCl level. As the salt concentration increased, germination percentage decreased in all varieties, moreover, seeds could not germinate in 300 mM NaCl, but the seeds who were bacterized germinated in a very small percentage, and the germs were abnormal. [ABSTRACT FROM AUTHOR]

Wheat is the crop with the highest global expansion, ensuring a balanced ratio between carbohydrates and protein substances. It requires a rational fertilization based on the dynamics of growth and root branching, closely related to the mycorrhizal association potential for high values of nutrients export from soil. Modeling the associative system of root with mycorrhizas can provide solutions to obtain stable yields. The root system is separated into clusters based on the root's architecture, the level of active and senescent mycorrhizal circuits being deteremined separately on each cluster. Root architecture provides a realistic picture of the momentary development of wheat plants. The level of mycorrhization indicates the function of absorption and transfer circuits. The evaluation of mycorrhization provides a number of parameters with high potential for the stability of mathematical models used for the installation and success of winter wheat crop. [ABSTRACT FROM AUTHOR]

Simultaneous evolution of plants with useful rizospheric micro flora has allowed the appearance of symbiotic partnerships between the radicular systems and symbiotical fungi. Natural grasslands represents a stable complex of ecosystems, where the competition capacity of each species is given by the expansion of the root system and branching, in addition to the ability to associate with mycorrhizal fungi. Festuca rubra and Trifolium repens plants were grown in pots, the percentage of each species in the mixture increasing/decreasing by 10 up to 10%. The mycorrhizal circuit was assessed based on the colonization parameters in the root system. For plants with similar proportions in the mixture a strong development of young roots is detected while increasing the association with mycorrhizal fungi. The colonization degree decrease is significant only for the high percentages of the specie in the experimental mixture. [ABSTRACT FROM AUTHOR]

A comprehensive and quantitative knowledge of ecological factors affecting crop production is needed in purpose to meet the challenge of growing world population with minimal environmental impact. Earthworms are target organisms both for scientists studying the biological component of soils and for farmers concerned with monitoring the quality of their soils. For the growing social interest to quantify the role of earthworms in ecosystems, a precise and accurate estimation of their diversity, abundance and biomass is needed. Earthworm ecologists tend to use methods of extraction with less use of chemicals, with this purpose we want to test some new environmental friendly methods like chili powder, mustard powder, mustard-vinegar suspension, in comparison with formalin 0.1% (10 ml in 8 l water) and 0.2% (15 ml in 8 l water). Efficiency of methods is compared in terms of earthworm species composition, numbers, biomass, ecological groups (epigeic, anecic, endogeic), development stages (adults + subadults vs. juveniles) and the mortality rates in the first week after sampling. [ABSTRACT FROM AUTHOR]

Mycorrhizal fungi constitutes a critical component of ecosystems, and through the involvement in the absorption and transfer, they have the ability to adjust the permanent and cyclical movement of nutrients in the entire ecosystem. Mycorrhizas have the ability to decrease inputs introduced into ecosystems, but allocation of ecosystem nutrient resources only to symbiotic plants may cause, in time, the destabilization of plant communities. Objectives of the study were to create a hierarchy of climatic factors (temperature and rainfall) and technological (fertilization + treatment) depending on the power to in..luence the mycorrhizal development. Analysis of colonization parameters variation is conducted using data collected from a ..ield experiment, over which were applied mineral and organic fertilizers under treatment with fungicides and zinc sulphate. Exploration of experimental data using cluster analysis revealed a good segmentation of variants fertilized and treated, based on the values of frequency and intensity of colonization in the root system of Festuca rubra plants. Temperature and rainfall had a signi..icant in..luence within the study period on the level of root colonization. Treatment with fungicide and zinc sulphate acted individually with a less pronounced effect, but more restrictive, the separation between clusters being made on the axis of treatments. Ecological factors determine the division of experimental variants in clusters de..ined by the ranges of colonization parameters, and by overlapping balanced fertilization completed with treatments over climate, the percentage of colonization frequency rises to maximum, individual expression of technological factors being optimal. [ABSTRACT FROM AUTHOR]

Vesicular arbuscular mycorrhizas act in the rhizosphere of plants as regulators of the processes of absorption and transfer of nutrients. High absorption potential show the involvement in nutrients cycle, reducing nutrient losses across the entire ecosystem and enhancing host plant resistance to stress factors. High biodiversity of grassland ecosystems is susceptible to the type of fertilization and maintenance of the land, climate contributing to the accentuation of plants sensitivity. The use of substances based on zinc in order to increase the root system of the plants and at the same time the surface on which will be established mycorrhizal fungi, or mulching, as an alternative to mowing, can act as stabilizers of the effect produced by mineral or organo-mineral fertilizers. Under the same fertilization conditions zinc sulfate acts, generally, to double the intensity and the colonization degree compared to mulching, and the maximum frequency is obtained only in the case of zinc sulphate application. [ABSTRACT FROM AUTHOR]

Soybean is one of the most important oilseed crop production and forage feed, representing 58% of total production of oilseeds in the world and 69% of protein intake from forage. The experience aims assessing the effect of single and combined fertilization with different doses of chemical fertilizers and zeolite, the elements of productivity and microbiological characteristics of soil on nodule number of soybean crop in the climatic conditions from 2013 year. Following the results it is found that fertilization based on equal amounts of urea and zeolite affects positively nitrogen fixing symbiosis. The effect is being stronger than if the fertilization is made by urea, fertilizer complex and zeolite, the recorded differences are large. Soybean production in 2013 specified the largest production increase 1.74 t/ha produced by the variant treated with 50 t/ha urea + 50 t/ha zeolite with no significant differences. [ABSTRACT FROM AUTHOR]

Intensification of natural ecosystems may be beneficial for a series of plants, which are favored to become the dominant at the level of grass cover. However, no matter how low would be the inputs applied, the first effects are observed in the symbiotic organisms of existing plants in the ecosystem. Adaptation of plants and soil microorganisms to environmental conditions have made the type and dosage of fertilizer applied to become factors with limiting effect on the balanced evolution of mycorrhizal fungi. For mycorrhizal colonization of Festuca rubra plant, climatic factors play a small role, from this consideration is necessary to identify the dose and type of fertilizer to ensure the stability in time of colonization parameters. To study the effect of increasing soil nutrient resources on the mycorrhizal colonization parameters in Festuca rubra, we set up an experiment with six degrees of fertilization, in addition to unfertilized control were applied to two types of organic fertilization and three types of mineral fertilization. Balancing the colonization and reducing fluctuations in time of colonization parameters is influenced in a high degree by nitrogen, whether it comes from manure or synthetic fertilizers. At the end of growing season it is observed the superiority of combined fertilizers (manure + NPK or Eurofertil mezocalc supplemented with nitrogen), which ensure the highest values of the colonization degree. [ABSTRACT FROM AUTHOR]

By studying mycorrhizal symbiosis, another important step is made in knowing the relationship between plants and soil microflora. Benefits that these symbiosis bring to plants and ecosystem are semnificative for the interpretation of physiological factors, like: extending the volume of soil accessible to plants, acquiring nutrient forms that would not normally be available to plants; for the ecosystem an important role is to soil structure and mechanical aggregation. In the pasture that we studied in the Apuseni Mountains we found as dominant species Carex hirta, percent in the floristic composition is 35-40%, and that is the primary reason for studying this plant. The study area is positioned at 2 meters far from the forest and the soil is caracterized by a big humidity - the subteran water is at a high level. To identify the influence of the forest, of the humidity and the relation with other plants in the pasture, first step was to find that plants of Carex hirta is colonized by mycorrhizal symbiosis. We harvest the plants with root from a 15 to 20 cm deep and we colored teh roots with a solution of ink with vinegar. The proposed method for diagnosis of mycorrhizal colonization on Carex hirta roots is specific for the area where the studies took place. [ABSTRACT FROM AUTHOR]

One of the main objectives for the future agriculture is to achieve high crop yields but also to maintain and improve soil quality. In 1995, the European Fertilizer Manufacturers Association (EFMA) prepared eight Booklets on Best Available Techniques (BAT) in response to the proposed EU Directive on integrated pollution prevention and control (IPPC Directive). In this Booklet it is show that ammonium nitrate is used extensively as a nitrogenous fertilizer. It is made exclusively by the reaction between gaseous ammonia and aqueous nitric acid, the production of which are covered in EFMA BAT Booklets 1 and 2 respectively. Reseeding of grassland may increase the mineralisation of organic material and lead to a greater amount of mineral nitrogen in soil, which can be leached during the winter-period. [ABSTRACT FROM AUTHOR]

Intraradicular installation of vesicular-arbuscular mycorrhizas on the roots acts to amplify growth and to increase potential yield. Extraradicular network of hyphae developed by mycorrhizas acts as an extension of the root in order to access the nutrients located in unexplored areas. The percentage of roots occupied by mycorrhizal hyphae fluctuates heavily under the influence of fertilization. The highest values of the colonization parameters were recorded with a high level of phosphorus fertilization applied as phasial input. High doses of mineral fertilizers with phosphorus applied with seeding favors the development intraradicular hyphal networks in wheat roots. [ABSTRACT FROM AUTHOR]

Winter wheat is a plant commonly used in agronomic systems. Potential for adaptation of this species has lead to connecting its roots with mycorrhizal symbiotic fungi. Mineral inputs, especially phosphorous, produces oscillation in the functioning of mycorrhizal mechanism. Autumn fertilization is beneficial for the arbuscular circuit, stimulating the plant to enter into symbiosis. The degree of colonization increases due to fertilization applied in the spring, but has low values when the supplement is missing. The maximum intensity of colonization is less than 66% and is achieved only under 27-13,5-0 NPK fertilization. [ABSTRACT FROM AUTHOR]

Oats has the capacity to develop a strong radicular biomass in the soil, alongside a good adaptability to cold climats, characters which favor it over other cereals in the areas with lower temperatures and high humidity. The simultaneous evolution with the symbiotic fungi allowed the premisis for a stronger installation of mychorrizal fungi, stimulated by the radicular exudate of the oats. The transfer of nutritive elements occurs between the fungi and plant, at the level of hyphal and arbuscular interfaces. The degree of mychorrization is greater in the senescent areas of the roots, while the transfer of nutritive elements thorugh the arbuscular circuit is higher in the freshly developed roots. [ABSTRACT FROM AUTHOR]

Maize has good biological particularities to exploit a high variety of agricultural land in different climatic conditions, due to a complex root system. The exploration of soil by roots developed by maize is dependent on the mycorrhization level, that increases the absorption capacity of nutrients from soil solution. The current experiment assesses the differences of mycorrhization colonization in the maize roots, by levels of radicular architecture. The level's division is performed based on the ramification point, by observing the hyphal network and arbuscular cirtcuit. The development of intraradicular hyphal networks is stronger in the aged areas of the root, while in the freshly formed segments the arbuscular impermanent structures are more visible. In the segments with high colonization intensity high soil nutrient absorbtion phenomenon occurs, while in the areas with lots of arbusculs predominant is the intense transfer of minerals between the two partners. [ABSTRACT FROM AUTHOR]

Vesicular-arbuscular fungi have a major contribution to the absorption of nutrients from the soil using extraradicular hyphae networks and exploring the soil areas inaccessible to plant roots. Studies on the role and benefits of mycorrhizal symbiosis showed the major influence that they have on plant growth and development, as well as adjusting character for the internal processes from ecosystems. The objective of this paper was to examine the changes in the level of colonization produced by applying fungicides as base for grassland ecosystems balance conservation techniques under changes in the way of maintenance applied to these surfaces. To analyze the level of colonization were collected roots of Festuca rubra, in 2010-2011, from an experiment with 6 graduations of mineral and organic fertilization located in Garda de Sus village, on each variant being additionally applied a fungicide treatment. Frequency of colonization is high and more stable under the influence of fungicide treatment overlapped on fertilization with manure supplemented with nitrogen, while in conditions of NPK fertilization and combined with treatment this parameter is strongly reduced. In both sampling periods, mineral fertilization act to reduce the level of mycorrhizal colonization, responsible for this being the fungicide application over fertilization. Applying fungicides over organic fertilization can provide high levels of mycorrhizal colonization, aspect that can be used in plant conservation techniques for grassland ecosystems, in terms of changing the way of maintenance or further abandonment. [ABSTRACT FROM AUTHOR]

More accentuated intensification of management from areas with high biodiversity may act to reduce the level of mycorrhizal colonization, while producing a reduction in plant resistance to stress factors. In the context of current climate drought is an common phenomenon, and depreciation of hyphal networks produced by mycorrhizae in root systems of plants increases their susceptibility to drought. In these circumstances, application of zinc over fertilization can increase the mycorrhizal colonization with increasing plant resistance to drought. The main objective of this paper was to analyze the potential for stabilization of colonization based on zinc application as a base for grassland ecosystems balance preservation under changes in the way of fertilization applied to these surfaces. The level of colonization was analysed in roots of Festuca rubra, during 2010-2011, samples being collected from an experiment with 6 graduations of mineral and organic fertilization located in Garda de Sus village, on each variant being additionally applied a zinc sulphate treatment. Application of zinc sulphate over fertilization with manure acts to reduce the level of frequency of colonization in the root system of plants of Festuca rubra, at the end of the growing season. At the same sampling period, a similar phenomenon is recorded under conditions of Eurofertil mezocalc fertilization. The intensity of the colonization varies greatly under the experimental conditions, higher values were observed at the end of the growing season for fertilization based on chemical nitrogen. During the period of plant maximum activity successful fertilizer recipes were without chemical nitrogen supplements in 2010, and NPK fertilization in 2011, these options ensuring the highest levels of colonization intensity. [ABSTRACT FROM AUTHOR]