Effects of converting forest to the rainfed lands on soil characteristics in a part of Zagros forests

The forest soils are the key parts of the Earth system that are globally degraded through anthrop induced deforestation, mainly converting to other landuses. The present study was conducted in Gazafolya village located in Merek watershed, Kermanshah, Iran, in which the soil quality of the forest and converted forest (rainfed lands) with the same topographic and geologic conditions were compared. To achieve the study purposes, soil sampling was carried out from the surface soil layers (0-20 cm) at the forest and its adjacent rainfed lands and analyzed in the lab. The data were described and geo-statistically analyzed using the SAS and GS+ softwares. The findings showed that there is no significant difference between soil fractions (sand, silt and clay) in two studied land uses. Bulk density (BD) in the forest and rainfed lands were 1.26and 1.32 gr-1cm-3 respectively, indicating significant (p<0.5%) higher level in the rainfed lands. Soil aggregate stability (SA) in the forest and rainfed lands were 63.62 and 52.65 %, respectively showing significant (p<0.5%) lower value in the rainfed lands mainly due to tillage practice. The results also showed that there were no significant differences between soil pH in forest and rainfed lands. It turns out that AS and BD were more imposed by converting forest to rainfed lands compared to the other soil characteristics.