Published in Scientific Papers. Series A. Agronomy, Vol. LXIII, Issue 2
Written by Olga VIZITIU, Irina CALCIU
One of the requirements of quality management of soils in general, and of arable soils in particular, is knowledge of the dynamics of physical and chemical characteristics especially of those which are the most sensitive under human activities. The main objectives of the present paper were to measure the physical, chemical and hydrological properties of soil collected from three agricultural soils, and to carry out the fertilization plan accomplished by using modern agricultural practices and technologies for a balanced fertilization in order to preserve soil fertility and environment. Soil samples were collected from three locations around South of Romania. The selected soils for this study are located in the Calarasi county, namely: profile P1 in Sarulesti location - Typical Chernozem (Calcic Chernozem), profile P2 in Tamadau Mare location - Cambic Chernozem (Haplic Chernozem), and Arges county respectively: profile P3 in Costesti location - Vertic-Stagnic Preluvosol (Vertic-Stagnic Luvisol). The investigated soils are medium to fine textured, starting from medium clayey-loam, clayey-silty loam to loamy clay. High contents in clay result in higher values for bulk density and penetration resistance. On the contrary, the saturated hydraulic conductivity (Ksat) of such fine textured soils records low values, the most significant decrease being encountered in the soil profile P3. The highest values of Ksat were recorded in the topsoil layer of the soil profile P2 where the total porosity was also the highest. The deeper layers of the soil profiles (> 80 cm depth) have lower values for S index. That means the soil physical quality as quantified by S is better in the topsoil horizons than in the subsoil horizons. The soil reaction values highlighted a lightly acid soil in P3, a lightly acid to lightly alkaline soil reaction in P2, and a lightly alkaline soil reaction in P1. The total nitrogen content of all three soils varied from very low-low to moderate values. The available phosphorus content ranged from very low-low in P3, low-high in P2, up to moderate-high in P1. As for the available potassium content, all the studied soils were moderately supplied. The fertilization plans were accomplished based on agrochemical studies. For each of the three sites cartograms were done for soil reaction, phosphorus and potassium. Also synthetic cartograms with the average values of soil reaction (pH), humus content, available phosphorus (PAL), available potassium (KAL), and nitrogen index (IN) for the established fertilization parcels from each location were realized. The fertilization plans contained economic and technical optimum doses - DOE and DOT (which ensure a certain level of crop yield at which the maximum benefit is achieved) for a four years crop rotation in case of P1 and P2 soils and five years crop rotation in case of P3 soil.
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