In this study, the effect of irrigation and anions introduced in the form of Mg(NO3)2, MgCO3 and MgSO4, which are biochemical indices of soil quality. Two laboratory experiments using complete randomisation were performed. First, one-factor experiment was carried out in triplicate. In this experiment, anion introduced with magnesium salt was the factor. The second experiment also was carried out in triplicate. In this experiment, the soil column for laboratory investigations of irrigated soil was used, anion introduced with magnesium salt was the first factor, and thickness of the soil layer was the second factor. The prepared material was irrigated nine times. In soil samples, the activity of dehydrogenases, proteases, alkaline phosphatase, amylase, and catalase was assayed. Based on these results, the biological index of fertility and enzyme activity number were calculated.
Anions introduced in the form of magnesium salts as well as irrigation caused significant changes in the enzymatic activity of sandy soil. The highest changes of dehydrogenases activity, alkaline phosphatase, protease and amylase were found in the soil with the addition of the carbonate anion. Calculated biochemical indicators of soil quality, biological indicator of fertility and enzyme activity index were increased after the introduction of the magnesium salt, especially in the thickness of soil 0–10 cm.
In the bi-factor experience (I-st factor . municipal sewage sludge dose: I . 0; II . 10; III . 20; IV . 30 t×ha.1; II . nd factor . texture: A . light soil, B . heavy soil) was examined for the influence of municipal sewage sludge from Deir the Ez the Zor City in Syria on solubility of chemical components in water, in the conditions of Syria climate. The results of conducted investigations did not prove in appointed proprieties a positive change of light and heavy soil. The salinity of soil grew independently from applied dose sewage sludge, it did not change significantly the organic carbon amount, but concentration and dissolubility, for example Zn, Pb and Na, in both soils grew.