Adelina Dumitras

Researches on Permeability and Soil Structure for the Implementation of Sustainable Landscape Architecture Practice

Sustainable landscaping incorporates a variety of practices that have been developed as a response to environmental issues and are used in all phases of landscaping. Bioretention offers a combination of local storm water management, improving urban green aesthetic value and facilitating increased polluted water retention function. To establish an important implementation condition of the bioretention system was approached the issue of permeability and soil structure in four different sites in terms of land use, in Cluj-Napoca, Romania. The environment is severely affected duet to accelerated anthropization, requiring interventions that apply the principles of sustainable development and minimize the impact of urbanization (Barbosa et al., 2012; Frondoni et al., 2011). The bioretention is based on natural principles and on the quality of the soil, and use a given area, designed to capture and filter out the water surplus from precipitation, through a soil mixture that allows water absorption and at the same time its usage by the existing vegetation (Prince George’s County, 2007; Atchison et al., 2006). Knowing the conditions for implementation of bioretention cells is a sine qua non condition. Although apparently, at first definition is perceived simplicity in design, construction and operation, after a careful study of specialized information is clear and without equivocation that without knowledge in detail of their, bioretention cells implementation may suffer in terms of efficiency, and the basic functions will not be fulfilled (Emerson et al., 2005; Gilroy and McCuen, 2009). One of the implementation conditions with significant influence on the constructive type of bioretention is the permeability and soil structure of the targeted site. Infiltration capacity of the most soils allows to precipitation with low intensity to infiltrate completely, except the case when the inferior layers are more compacted than the soil layer from the surface (Morel-Seytoux, 1978). A high intensity precipitation generates substantial runoff because the infiltration capacity of the surface soil is exceeded even if the underlying soil is still dry. There is a classical assumption, namely: the ability of infiltration of the soil is higher at the beginning of a precipitation event and decreases over time (Willeke, 1966). Natural infiltration is significantly reduced in urban areas due to several factors: decrease of the areas with exposed soil, removal of the surface soil and exposure of the inferior layers, soil compaction during construction activities (Characklis and Wiesner, 1997; Eriksson et al., 2007; Lin Yu-Pin et al. 2007). Pitt et al. (2002) asserts that systems which rely mostly on vegetated infiltration surfaces gaining popularity and seem to be a more robust solution than conventional drainage and infiltration systems. In this paper, to establish an important implementation condition of the bioretention system was approached the issue of permeability and soil structure in four different sites in terms of land use, in Cluj-Napoca. Materials and methods For the research of the bioretention systems implementation conditions were selected four different sites in terms of land use located in the city of Cluj-Napoca, Romania: high density residential area, low density residential area, commercial area, and industrial area. For the determination of the permeability and soil structure, in the selected sites were performed four geotechnical drilling. Research from geotechnical point of view aimed to establish lithological succession, particle size distribution, and degree of nonuniformity, volumic weight, specific density and soil permeability in the studied areas, the classification of studied soils in the four hydrological groups. Water permeability was carried out in the laboratory using the method of permeameter with constant gradient. Figure 1 shows the location of geotechnical research work. The maps were drawn at different scales, depending on the surface area: 1:1000, 1:2000 and 1:5000 scales. Results and discussion After the analysis of texture on the soil profiles were found large oscillations under the aspect of the three categories of particles so that depending on their percentage, was determined the soil textural class from studied sites. Based on the results presented in Table 1 were determined the following soil types: silty clay in the high density residential area, loamy dust in the low-density residential area, dusty sand in the commercial area, clay in the industrial area. The site soils from studied sites were included in the six textural classes for soils in Romania established by Chiri׳ (1955) based on the percentage content of each granulometric fraction. We could enclose into these categories only the soil from the commercial site and from industrial site. The soil from the industrial site falls into the category of the soils with clay loam texture, while soil from the commercial site falls under the category with sandy loam soils. With regard to these characteristics of the soil from studied urban areas and their influence on the implementation of bi-

Irrigation and Fertilization Management Effect on Chinese Cabbage Chemical Composition

ABSTRACT Chinese cabbage is a leafy green with great economic potential, mostly in those areas where it has not yet been widely cultivated, but its demand is increasing, due to its high nutritional and therapeutic value. The experimental factors involved three cultivars of Chinese cabbage, different irrigation, and fertilization treatments. The main aims of the present research were to establish the influence of water and fertilization management on Chinese cabbage chemical composition in an organic cropping system and to determine relations between the organic fertilizers and cabbage leaf macroelements, essential microelements, and heavy metal concentrations. The results showed that sheep manure was richer in almost all the studied elements, including heavy metals; plants fertilized with this manure have higher levels of heavy metals; irrigation had a secondary effect on the decreasing heavy metal concentration in plants; and plants fertilized with biofertilizers showed high amounts of potassium (K), magnesium (Mg), sodium (Na), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn).