Effect of different land uses on some physicochemical and micromorphological properties of calcareous soils in East Azerbaijan Province, northwest of Iran

Vegetation is one of the active pedogenic factors, although its influence on soil micromorphological properties has received relatively little attention. Therefore, the present study aimed to evaluate the effects of different land uses on selected chemical and physical soil properties and to investigate the resulting changes using micromorphological analyses in the Alkhalaj Dam area of East Azerbaijan Province, northwest of Iran. For this purpose, surface soil samples (۰–۳۰ cm) were collected from four different land uses—wheat, alfalfa, rangeland, and fallow—within plateau physiography and were subjected to physical, chemical, and micromorphological analyses. The results showed that soil texture remained unchanged across all land uses, except under wheat cultivation. Organic carbon, nitrogen, phosphorus, and potassium contents were highest in fallow and rangeland land uses and lowest in wheat land use. Calcium carbonate equivalent exhibited the highest values in fallow and wheat land uses, while the lowest values were observed in rangeland. Micromorphological observations indicated that voids in rangeland and fallow soils exhibited a much higher degree of development than those in agricultural land uses, with large voids occurring to a very large extent in rangeland and fallow soils. However, with the conversion of land use to agriculture, the abundance of coarse packing voids was greatly reduced and platy voids were formed. Overall, the results demonstrated that vegetation primarily influences soil microstructure and void characteristics and, consequently, soil physical properties. This study highlights the importance of conservation-oriented management practices to prevent soil degradation resulting from unconventional land-use changes.

کلیدواژه ها:

Alkhalaj Dam area ، Chemical properties ، Land use ، Micromorphology ، physical properties