Effect of land-use change on Carbon and Nitrogen dynamics and selected soil fertility properties in forest ecosystems of Perdanan region of Piranshahr, West Azerbaijan

Using different tillage systems following unscientific land-use change lead to accelerated decomposition of soil organic matter. This study was performed to investigate the effects of forest conversion into rangeland, garden and agriculture on organic carbon and nitrogen dynamics as well as mineral nitrogen forms (nitrate and ammonium) contents. To this aim, 40 soil samples (0-15 cm depth) were taken from different land-use classes including forest, rangeland, garden and agriculture in Perdanan region of Piranshahr in West Azerbaijan province. Organic carbon, total nitrogen, nitrate, ammonium and a number of soil properties were measured in soil samples. The results showed that organic carbon, total nitrogen and the ratio of total nitrogen to inorganic nitrogen (Nt/Nmin) were shown to significantly decrease by 44, 46 and 49 percent, respectively due to land-use change from forest to agricultural cultivation. The mineral nitrogen forms in garden and agriculture classes increased approximately by 80 percent. In addition, soil EC was shown to decrease due to land-use conversion from forest to garden and agriculture. Moreover, Calcium carbonate percentage and pH in the garden were significantly higher than the other land-use classes. The highest amount of exchangeable Ca and Na were found in agricultural land-use. Therefore land-use change from forest to agricultural systems is concluded to reduce soil quality and organic matter in long-term due to decreasing organic matter inputs and exerting different tillage activities.