عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Gully eroaion is one of the developed forms of water erosion which redolent of
surface soil destruction in the lands. Recognize of the effective factors in happence of
gully erosion and it’s zonation is a basic implement to manage and control this
phenomenon. this study has been performed with aim of recognizing the effective
factors on the gully erosion making and it’s zonation in the watershed of Torood. The
most important effective factor in happending gully erosion such as slope, aspect,
litology, land use, distance of communications network, land and canopy cover were
selected as the most important factors on gully development and their layers were
provided in GIS environment. All three gullies in the area were selected for the study.
For each gully, three soil samples were collected from 25, 50 and 75 percent of gully
length and three from outside of gully for comparison. This Samples have examined
from the view of Gypsum, Organic Carbon, Salinity, Saturation Percentage, Lime,
Sodiun Absorption Ratio and PH. Gully erosion zonation map of Torood watershed
was prepared using 1:40,000 areal photos of 2001 and field measurements using GPS.
The area covered by gully erosion in each class of effective factors, were computed by
overlaying gully erosion zonation map with effective factor layers. Effective factors
and their classes in related layers were weighted using Multi Class Maps
method.Results demonstrated that 88 percent of gullies are located at high to very high
classes of vulnerability zones. Soil analysis also indicated that salinity, gypsum and
sodium absorption ratio in the gullies are higher and the amount of organic carbon is
less than that of surrounded areas. But, there were no significant difference between
saturation percentage, lime and pH in the gullies and surrounded areas.