Impact of land use changes from rangeland to rain-fed land on soil organic matter and nitrogen in Kermanshah and Kordestan provinces (Case study: Lille, Ravansar and Razavr watersheds)

This study aimed to determine the effects of land use changes from rangeland to rain fed land on some qualitative soil factors such as nitrogen and particulate organic matter in Kermanshah (Lileh and Ravansar watersheds) and Kordestan (Razavar, Kalucheh and Morvarid watersheds) provinces. A completely random design method was used to collect soil samples from each land use and watershed. The data was then analyzed using un-paired t-test. The results showed that land use changes from rangeland to rain-fed land had significant impact on qualitative soil factors. The kind and severity of the changes varied due to the kind of planted species in agricultural land. Land use change from Astragalus microcephalus to Cicer arietinum in Lileh, total organic matter, total nitrogen content, particulate organic matter-C (POM_C) and –N were significantly decreased 32%, 55%, 48% and 24%, respectively. Land use changes from Astragalus acanthus to Triticum sativum in Ravansar had no significant changes on POM-C and TOM, but decreased TN and POM-N 10% and 4%, respectively. In Kalucheh and Morvarid watersheds, POM-N was decreased 69% and 40% as a result of land use changes, respectively (P<0.01). In overall, the results showed that the negative impacts of land use changes in natural communities could be minimized by planting appropriate agricultural plants.