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The current work aims to evaluate the effect of different periods of organic farming on some soils qualities compared with the traditional system. Several farms varied in their soil nature and periods of practicing organic farming system were chosen. The farms are located in Belbes, ElManayef, El-Fayoum and ElBehera areas. Moreover, the study also involved adjacent traditional managed farms. The evaluation was based on the weighted values of the physical, chemical and biological properties of the 0-50 cm and 0-100 cm soil depths. The considered soil properties were soil organic matter (SOM); bulk density; porosity; available water; penetration resistance, mean soil particles weight diameter (MWD), cation exchange capacity and total microbial count. The obtained results indicated that soil biological parameters were less important than the physical or the chemical factors. Principle component1, (PC1) scores indicated that 79.97% and 78.05 % of total variance are attributed to the 0-50 cm soil depth of the organic and conventional managed soils, respectively. In the meantime, 75.72 and 71.94 % are related to the 0-100 cm soil depth for the two farming systems, (Organic and conventional) in the same sequence. The only significant factor contributing to PC2 was total count; PC2 indicated that (10.29 and 10.87% of the total variance are accounted for 0-50 and 0-100 cm soil depth of organic farming as well as 15.3 and 16.68% of the total variance for 0-50 and 0-100 cm soil depth of conventional farming system, respectively. INTRODUCTION It is well know that the inherent soil characteristics are those related to the soil forming factors; i.e., climate, parent material, ... etc, whereas the dynamic soil properties are influenced by the management practices imposed by mankind. Both are very important to sustainability. Evaluating inherent soil properties and their effect on land use and the suitability of each soil for various uses are the basic concern of soil surveyors. On the other hand, dynamic soil quality focuses on the status of specific soil due to the relatively recent management practices (Karlen et al 1997; Doran and Parkin 1994). Doran and Parkin (1994) defined soil quality as ״the capacity of a soil to function״. Meanwhile a more complete definition of soil quality was offered by a committee appointed by the Soil Science Society of America (SSSA) as ״soil quality is the capacity of a specific Kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality and support human health and habitation״. Doran and Parkin (1994) also stated that soil quality assessment is conducted by evaluating indicators. These indicators can be physical, chemical and biological properties, processes or characteristics of soils. Jawson (2001) mentioned that physical properties include soil structure, aggregate stability, wind and water erosion. Chemical properties include pH, total plant nutrients, and salinity. Biological properties include root microbial count and other organism-driven processes such as respiration, mineralization, immobilization and denitrification. Since it is impractical to measure every ecosystem or soil property, many researchers proposed a Hoda Elia; Talha; Afifi and Al-Hassana Abu-Gabal Arab Univ. J. Agric. Sci., 17(2), 2009 386 minimum data set which is the smallest set of soil properties or indicators needed to measure or characterize soil quality. Larson and Pierce (1994), Doran and Parkin (1996) proposed a minimum data set (MDS) consisting of an array of soil chemical, physical, and biological characteristics as basic indicators of soil quality. The soil physical indicators include soil texture, rooting depth, infiltration, water holding capacity and bulk density. Soil chemical indicators embarrasses electrical conductivity, pH and extractable N, P, K. Soil biological indicators evolve microbial biomass, C and N, potentially mineralizable; N and soil respiration. However, Seybold et al (1996) reported that the proposed indicators should be related to soil function and quality. On the other hand, Vance (2000) and Doran (2002) stated that because of its positive influence on several soil processes, crop productivity and environmental quality; therefore soil organic matter (SOM) is often considered the single most important indicator of soil quality and sustainable land management. Moreover, Van Noordwijk et al (1997) stated that SOM is a soil property that is generally most sensitive to crop management. The current work aims at evaluating the impact of organic farming system on soil properties, especially the physical ones that determine soil quality. MATERIALS AND METHODS

IMPACT OF MANAGEMENT SYSTEMS ON SOME SOILS QUALITIES IN EGYPT