CORRELATION BETWEEN THE SOIL REACTION AND THE CONTENT OF ORGANIC CARBON AT A TYPICAL LUVOSOIL

The soil’s reaction defines and expresses its ability to maintain in solution a certain activity of hydrogen (H +) and hydroxide (OH -) ions, because the soil acts as a donor or acceptor of protons (H + ions) (Rusu et al., 2005). The term of humus defines the organic inanimate component in the soil resulting from the conversion by micro organisms of crop residues and is quantitatively assessed by the organic carbon content increased by 1.724 times. This ratio represents the average ratio between the mass of humus and the average content of carbon in humus (100: 58% C = 1.724). Humus is one of the most important components of soil. It contributes to power the plants with nutrients, it influences the water holding capacity, temperature, aeration and other properties of the soil (Davidescu et al., 1999). Knowing the humus content is strictly necessary for the assessment of soil fertility, knowing that, humus fulfills multiple functions: reserve and source of nutrients; component of the complex colloidal with an important role in the retention of cations in the soil structure and in the water retention; stimulates the activity of microorganisms. So humus is the soil fertility main determinant. Knowing the pH value is of great importance in the plant and crop nutrition process, as each species prefers certain pH conditions for their proper development. This paper presents the correlation between soil’s pH and the content of organic carbon, respectively humus on a typical luvosoil from Livada