Legumes, of which Vicia sativa is one, can be used successfully as green fertilizers. They can contribute to improving the characteristics of soil: density, porosity, humus accumulation in the soil, and they live in symbiosis with nodule bacteria, which can make  atmospheric nitrogen fixation happen.  (Clark, 2007, Jeon et al., 2009). Plants can foster their own growth, by chemical changes (the case of the available nutriments) and biological changes at soil level (Niu Et Al. 2007). Through some substances named elicitors, the plant select the microflora in the area near the root, and together with this selection, some other changes are taking place in the dynamics of vital processes in the soil. Among the sources of energy used by microorganisms, the cellulose in plant debris contains the largest quantity of organic carbon. Because of the microbial decomposition of this polysaccharide, the humus content of soil increases. Because of the contribution that cellulolysis has in increasing the fertility potential of soils, the study in this paper is focussed on this vital soil parameter. The soil, moderately glazed Eutric Cambisol, is to be found in Ciacova commune, Timis County. The soil was sown with common vetch (Vicia sativa). Soil lab analysis was performed in the autumn of 2011. In order to determine the cellulolytic potential, we took 10 soil samples from the edaphosphere and near-root area of species Vicia sativa, plus a control variant. The sapling depth was between 0 and 20 cm. The method for finding the quantity of decomposed celluloses was the one presented by Stefanic (2006). The study revealed positive development of this vital process in the area near the root, under the influence of vegetal exudates and moisture index. These chemical changes in the near-root area lead to selection of the microbial community, while at the same time inducing increased microbial activity. The decomposing process and the moisture content depend on the humus in the soil. By reference to the edaphosphere, vicinity is noticed between the control variant and the near-root area. The % variance on PC1 is 80.997 and on PC2 19.003 so we choose to represent the eigenvalues only on the most significant axis (PC1).

cellulolytic potential, far rhizosphere zone, near-root area, Vicia sativa

Presentation: oral