Studying the Effects of Rangeland Conversion to Agricultural on the Chemical and Physical Soil Properties (Case study: Gonbad Area, Hamadan Province)

Destruction of land due to land use change in arid and semi-arid areas has endangered sustainable land use. This research was carried out to investigate the effect of rangeland use change to agriculture and study the physical-chemical properties of soil in Gonbad area of Hamedan province.

In this study, 6 soil samples were prepared from soil surface according to the type of land use change. After removing soil samples and preparing samples, some physicochemical properties of soil including Acidity, Electrical Conductivity, Silt, Clay, Gravel, Nitrogen, Potassium, Sodium, Organic Matter, Calcium and Magnesium were measured. In this research, Soil Texture was determined by hydrometric boiling, Acidity and Electrical Conductivity, using pH meter and EC meter, Organic Oatter using Walkley-Black, Calcium and Magnesium by titration, Sodium and Potassium using flame photometer and Nitrogen were measured by Kjeldahl method.

After analyzing, it was determined that the change in the use of rangeland to agriculture caused a significant decrease in Acidity and Potassium at 5% and Organic Matter at 1% level. Average Nitrogen content in agricultural was 0.18% and in rangeland was 0.9% (p<0.01). There was no significant difference in Soil Texture components, Electrical Conductivity, Sodium, Calcium and Magnesium with land use change. The amounts of Silt, Sodium, Calcium and Magnesium in rangelands were more than agriculture area.

The results of this study showed that the land use change causes changes in the chemical and physical properties of the soil. One of the most important changes was soil texture alteration caused by selective soil erosion.The results of this research showed the necessity of paying more attention to the development of land management and land use planning programs according to the capabilities of the studied area.