Investigating environmental factors controlling soil organic carbon in rangelands of arid regions (case study: Yansi region of Gonabad)

Rangelands of arid and desert areas despite the insignificant vegetation cover, but due to the large global scale, more than one third of the surface and underground carbon reserves have landed. Organic carbon dioxide management in rangelands requires knowledge of the amount of organic carbon and the factors that affect it. The amount of soil organic carbon is the result of the balance between the carbon that is added to the soil and the carbon released from the soil by watering, carving and erosion. The present study evaluates the changes in soil carbon and how they relate to environmental parameters in dry and semi-arid rangelands. For this purpose, the rangelands of Yansi region of Gonabad have been selected as a model of arid regions of the country. The aim of this study was to study the effect of soil characteristics, land management and vegetation cover on soil organic carbon changes. Therefore, in the present study, the study of the relationship between organic carbon of soil and some soil characteristics and vegetation cover and determining the most important factors affecting soil organic carbon are among the studied variables. The study area in the Yancei region is located in the geographical area '20 and 32 ° to 39 ° 32 ° north latitude, and '57 ° 59 ° to 13 ° and 60 ° longitude. The average rainfall and temperature is 157 mm, 14 ° C. Vegetation inventory of the area was carried out using cross-sectional method. The measured environmental parameters are: altitude from the sea level, average annual rainfall, average annual and average annual precipitation, acidity, conductivity, calcium, magnesium, sodium, potassium, phosphorus, carbon Organic and soil texture. To determine the environmental factors affecting soil carbon changes, principal components analysis (PCA) has been used on the values of factors and correlation coefficients as a criterion for the similarity between the plots. The results of main component analysis showed that vegetation, climatic, maternal and altitude parameters have a great role in soil organic carbon control in these rangelands. The soil carbon content was positively correlated with clay (39%), sand (33%), potassium (30%) and magnesium (21%), and negative correlation with altitude (32%), nitrogen (18%), precipitation (39%), moisture content (39%) and coating (34%). In this study, it was determined that in the dry and semi-arid rangelands of Iran, soil organic carbon is primarily affected by rainfall and temperature, soil texture, elevation and vegetation. Therefore, a combination of different factors, especially those mentioned above, is needed to understand and estimate the soil organic carbon levels and without considering the key controller factors together, any estimation of the organic carbon of the soil would be unreliable.