Search Results

You are looking at 1 - 3 of 3 items for

  • Author: Monica Dumitrașcu x
Clear All Modify Search
Open access

Matei Sorin, Matei Gabi-Mirela and Dumitrașcu Monica

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

Monica Dumitrașcu, Mihaela Lungu, Sorin Liviu Ștefănescu, Victoria Mocanu, Gabi Mirela Matei and Rodica Lazăr

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

Mihaela Lungu, Sorin Liviu Ștefănescu and Monica Dumitrașcu

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.