determination of suitable lands for sowing alkaligrass puccinellia distans (case study: agh-ghala rangelands, golestan province, iran)

annually, 200 ha of agh ghala rangelands in golestan, iran are under alkaligrass puccinella distans's cultivation but the failure in the identification of appropriate sites for seed sowing may result in high costs of cultivation. the current study aims to reduce such costs through the examination of apt sites to grow p. distans in northern rangelands of agh ghala golestan, iran. because of the same topography and climate of the study area and gomishan rangeland in closure where the plant grows and seeds are collected, a map of photomorphic units was first prepared using satellite images of landsat 5 (28.05.2011) and google earth. then, some soil physical and chemical properties including texture, ec, ph and organic matter were measured in three photomorphic units. in each photmorphic unit, three transects (length of 150 m and intervals of 50 m) were set up. along each transect, three soil samples at the depth of 0–10 cm (9 samples in each photomorphic unit) were taken and transferred to the laboratory. in order to verify the suitability of the predicted photomorphic unit, the seeds had been sown in the above mentioned key area of each photomorphic unit and p. distans cover percent was estimated. data were analyzed and means comparison was done between the units using tukey method. incorporating all the obtained data led to predict the location of appropriate photomorphic unit for the seed sowing of this plant. despite the initial prediction of suitable seeding location (photomorphic unit 3), results indicated that the photomorphic unit 1 was the most successful area which had a lower depth of underground water table and  higher ec and vegetation cover percent as compared to two other units. based on the findings of current study, it is recommended that seeding operation should be concentrated on photomorphic unit 1.