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  • Author: Dumitrascu Monica x
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Soils from HNV agriculture systems as source of microorganisms with antifungal activity

Abstract

Soils from rural zones with high natural value (HNV) agriculture systems are an important source of beneficial microbial species that can be useful for various biotechnological purposes, such as transfer of suppressiveness against plant pathogens from suppressive to disease-inducing soils by using inoculation with antagonistic selected strains. The main goal of the paper was to present the results of the research carried out on strains isolated from soil microbial populations in HNV agriculture system (Mureș county, Romania) responsible for specific suppressiveness against soil-borne phytopathogens. The dual culture method was used for assessing the mechanisms involved in antagonism against a plant pathogenic strain from genus Fusarium. The global microbial activity measured as soil respiration was intense. Total counts of bacteria and fungi estimated by dilution plate were also high. The community of heterotrophic aerobic bacteria included 13 species. Associations of fluorescent pseudomonads and actinomycetes were dominant and presented antagonistic activity against Fusarium. Twenty fungal species presented cellulolytic capability evidenced by growth on culture media with cellulose as sole source of carbon. Over cellulolytic capacity, the selected isolate of Trichoderma viride presented antagonistic activity against pathogenic Fusarium strain. Both biochemical mechanism and hyperparasitism were evidenced as involved in its antifungal activity.

Open access
Differences in organic matter quality, chemical and microbiological characteristics of two Phaeozems under natural and anthropic influence

Abstract

The soil degraded and changed by the anthropic activity must be monitored and the awareness of the intrinsic processes will allow a pertinent analysis of the effects of the application of the new technologies on the management and the sustainability of the soil.

Two natural and anthropic Phaeozems were analyzed from the point of view of chemical, microbiological characteristics, quality and composition of organic compounds.

Total values of microbial biomass and bacterial and fungal counts were generally twice higher in Calcaric Phaeozems than in Verti-Stagnic Phaeozems.

The content of humic precursors in Calcaric Phaeozems was quantitatively higher than that determined in Verti-stagnic Phaeozems, with a total content of phenols of 14.6mgGAExg−1d.m., polysaccharides and proteins of 97mgxg−1, respectivelly 16.6mgxl−1.

The ascending chromatograms showed specific distribution and higher density of the organic compounds in the CAFT sub-fraction of the Verti-stagnic Phaeozems. Pfeiffer specific chromatograms revealed an enzyme activity much higher than average at the Verti-stagnic Phaeozems, with a well-characterized functional diversity. The nutritional reserve appeared increased but poorly diversified in the Calcaric Phaeozems. Humification processes are intense, colloidal substances are present, the mineral component is very well integrated in the organic material at the Verti-stagnic Phaeozems and complex protein content is well revealed especially in the Calcaric Phaeozems.

Capillary dynamolysis reflected a characteristic pattern of Phaeozems soils, with particularities for each soil type, represented by colors, contours and particular forms of the specific structures developed.

Both soils presented good conditions for sustaining vegetation either natural or cultivated but results indicated that anthropic intervention determined a more dynamic mineralization of organic matter. Further monitoring of soil organic matter dynamics is needed and adjusting management practices for conservation of biodiversity and global ecosystem protection against the effect of anthropic intervention.

Open access
Soil Fertility Assessment of an High Natural Value Eligible Area in South-Eastern Transylvania

Abstract

As low-input environmentally friendly agricultural practices are currently associated with the delivery of a wide range of public goods and socioeconomic benefits, the strategy of European Union in mitigating climate change effects, protecting environment and ensuring public health has, among others, focused around preserving the High Natural Value (HNV) areas. About a quarter of the land in Romania is potentially covered by HNV farming and eligible for associated support payments, mostly along the chain of the Carpathian Mountains. Since soil systematic data on HNV area are scarce, recent research developments currently undertake to build up a first national HNV soil data base.

Soil fertility state in a HNV payment eligible area of south-eastern Transylvania was studied in seven in-depth dug profiles and seven additional shallow dug profiles. Soil samples were taken by genetic horizons as well as agrochemical samples from the upper soil layers (0-20 cm). Physical, chemical, and microbiological analyses revealed that the studied soils have a medium clayey loamy texture, good fertility and are subject to an adequate HNV management in the area, as the analytical values mostly range in favorable intervals for plant growth and nutrition. Thus, soil reaction is moderately acid up to slightly alkaline in the presence of carbonates, the soil organic matter, generally well mineralized, reaches fair levels and the high and very high cation exchange capacity ensure good conditions for plants growth and nutrition whilst nitrogen and potassium supply is adequate. Phosphorus is the only element in short supply – a situation often encountered in Romania unfertilized soils. Soil bulk density and total porosity are also favorable for root growth and spreading and plant nutrition. Microorganisms’ activity is diverse and is also adequate for plant nutrition.

Open access
Quality of Organic Vegetables Grown in Two Certified Sites on the Outskirts of Bucharest Municipality

Abstract

Soil fertility properties, irrigation water quality, mineral nutrition, and some vegetables mineral composition were studied in the frame of a project regarding yield quality monitoring in certified organic vegetable farms, in two farms placed on the outskirts of Bucharest Municipality which provide products for the town’s organic market. Chemical analysis of the soil samples collected from the two farms reflects a good fertility, close to the natural one of this region soils, with well-balanced organic matter, total nitrogen, accessible phosphorus and potassium contents. The nitrates contents concord with the plants nutrition demands and don’t present the risk to accumulate in vegetables or to leach into the groundwater. Slightly increased microelements, both total and soluble forms, occur. Soil microbiological properties are favorable for vegetable plants growth. A good biodiversity is noticed. There are differences between soil properties in open field and greenhouses, induced both by the type and degree of mechanical works and materials applied for fertilization and plant protection. Good conditions are generally created for plants mineral nutrition. Mineral nutrition status of the vegetables grown in organic conditions, assessed by the leaves mineral composition, doesn’t differ from the one of the vegetables grown in conventional conditions. The vegetables (fresh material) harvested from the two studied farms have good, even high, concentrations of mineral elements important for the yield nutritional quality. The excessive microelements quantities noticed in soil don’t transfer in the yield, so the latter quality and nutritional properties are not altered.

Open access
Solar Energy Industry as a Part of the Romanian Renewable Energy Industry: A Multi-level Territorial Approach

Abstract

The green economy emerges differently depending on each region particular features, as well as local economic strengths and weaknesses; solar energy however, represents the way regional and local natural potentials are valorized. The current paper brings to our attention aspects related to the economic and legislative factors influencing the use and territorial distribution of solar energy, as a component of the Romanian renewable energy industry at all territorial levels: the national characteristics of the use of renewable energy resources are highlighted through the analysis of dynamics of official statistical variables (National Institute of Statistics); at regional and county levels, the analysis highlights the territorial differences in the use of solar energy; analysis at local level reveals the environmental and socio-economic effects of the of solar energy use (i.e. photovoltaic parks), as indicated by the information provided by a questionnaire survey carry out in Giurgiu County (case study).

Open access